Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, 850 California Police Carburetion
Parts, supplies & service
Table of contents
- Accelerator pump check valve/ball
- Air box
- Air filters
- Amal carburetor information
- Carburetor balancing/synchronizing
- Carburetor balancing/synchronizing without carb sticks
- Carburetor cleaning with boiling distilled water
- Carburetor cleaning with Pine-Sol
- Carburetor float bowls - checking for leaks
- Carburetor rebuild - Dell'Orto VHB
- Carburetor return springs - lighter springs for Dell'Orto VHB
- Carburetor - setting them up
- Carburetor - single manifold
- Dell'Orto PHF 30 carburetor fitment
- O-ring for sealing the carburetor enricher cable holder
- Intake manifolds
- Pinging
- Separating the carburetor from the intake manifold
Accelerator pump check valve/ball
Updated: Prior to 2007 Dec 11
There is a little ball inside the accelerator pump that serves as a check valve. The ball is solid and made out of some sort of plastic that is very resistant to nasty chemicals. I've even accidentally let them soak in carb cleaner only to find no damage. They seem to last forever, but if you need to check yours to see if it has worn, the size should be 3.175 mm or 0.125 in or 1⁄8 in.
Air box
Updated: 2012 Apr 26
Please see the follow-up information at the bottom of this section.
The stock air box could have been designed better than it was. Although a little inconvenient from a maintenance perspective, the real problem is non-filtered air leaks. The rubber boot that connects each carburetor to the airbox deteriorates over time and does not create a tight seal, thus allowing dirt into the engine.
Greg Field provided these instructions to me:
I just silicone the boot to the box. Silicone it, weight the boot with something heavy enough to smoosh the boot's rim to the airbox, and leave the weight in place for 24 hour until the silicone is dry.
These boxes are [very difficult] to install if you don't do it right. The trick is to detach the left carb by undoing the three screws holding the manifold to the head. Put the box in place, worming the right boot spigot over the right carb's inlet. Then worm the left carb's intake into the boot, and tighten down the three manifold screws to affix the carb. Then “wiggle” everything to its best alignment and so there is minimal twisting and puckering of the rubber of the boot. Insert and tighten the three airbox screws. Tighten the hose clamps to the carbs. Also, you may want to mess with the jetting some. I found that 40 pilots and 140 mains worked better than the stock jets. Better gas mileage, too, and no fouled plugs.
I do not like K&Ns because I do not believe they filter air very well. They do flow air very well and strain out the big stuff, though. The stock air filter is probably not much if any better at catching grit than the K&N individual elements or single element for the airbox would be. If you hold either up to the light, you can see right through. And the stock element doesn't even get oil to help catch stuff. Unfortunately, there really isn't a better option for the loops (a paper element for the stock box would be ideal), so I ran a K&N element in the stock airbox.
Why the box? It keeps the K&Ns out of the sun, so they stay oily longer (really, they do not filter at all if not wet, and 80 percent of the individual pods I see on bikes are dry as a desert) and clean longer because dust and dirt settles on the box rather than the exposed filter. Also, it significantly reduces intake noise. This was important to me.
The airbox may also reduce performance on some bikes. On mine, it seems not to have, though I never did any dyno runs to confirm that. My bike acquired a reputation for going faster than most people really wanted to go, so I'm pretty sure the airbox wasn't hurting me much.
Greg Field's instructions were very helpful when I first installed the stock air box on my Ambassador. Here are a few additional notes from my experience:
- When I first siliconed the boot in place, I weighed it down, but not enough. Only the edge got “glued” to the airbox plate and it broke off when I first tried to insert the velocity stack into it. The second time I really weighed it down so that the boot lip was flattened against the plate. I haven't had any trouble yet.
- I've found that I can remove either carb without disturbing the airbox (and leaving the boot in place) simply by removing the three bolts that secure the intake manifold to the head.
- I've not noticed any performance decrease on my Ambo. On the contrary, I'm quite certain it runs stronger with the velocity stacks than without. I don't believe my air intake is restricted any more with the UFI than with the K&N pods. No data here, just my opinion.
- The box does make things quieter…and let's me hear other sounds the bike is making…I like that.
Follow-up
I no longer use the original air box. I like the look of the original air box and I like that the original air box reduces intake noise. However, I continued to have difficulty keeping the rubber boot sealed (glued) to the air box and maintenance operations are a lot more troublesome with the original air box.
Air filters
Updated: 2012 Apr 26
Replacement air filters for the original air box
Replacement air filters for the V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, 850 California Police motorcycles are limited to the following:
- UFI part number MG# 12113600
- K&N part number MG-0100
- UNI MG-1
| Download Name and Link | File Size | Number of Pages in File |
|---|---|---|
| 28 KB | 1 page |
To view PDF files, you will need to download and install the free Adobe Acrobat Reader.
NOTE: If you have trouble viewing PDF files inside your browser, try saving them to your computer (right-click the link, then choose the save option). Then, open each file directly in Adobe Acrobat Reader.
Air filters that replace the original air box for models equipped with Dell'Orto VHB carburetors
Velocity stacks are important for optimal performance. I do not recommend any air filter solution that necesitates removal of the velocity stacks. Furthermore, I am not a proponent of modifying the original velocity stacks to accomodate aftermarket pod filters. Original velocity stacks are getting harder to come by and machining them makes the non-original forever.
-
UNI part number UP-4182 (Contributed by Mark Etheridge of Moto Guzzi Classics) -
These filters clamp directly to the original velocity stacks and do not require any modification whatsoever.
Follow-up
I've fit these filters to an Eldorado. The filters fit well to the orginal velocity stacks, but are so long that they push into one another significantly in the center. This configuration places a constant stress on the filters and must certainly decrease the serviceable life of the filter. In short, I will not choose to use these filters again.
-
UNI part numbers U801 and U802 (Contributed by Mike Tiberio on the Yahoo! Loopframe_Guzzi news group.) -
Greg, I have been a big fan of UNI's, right up until my bike backfired while trying to start it, and they caught FIRE!!!
That said, you can fit 2 rubber flanged unis to your bike, but a system I devised ended up cheaper, and neater IMHO. I got a single sock (no rubber flange) filter of the appropriate ID and about 8 in long I believe. I cut center out of the closed end so I ended up with a foam tube. Leaving the spring inside to prevent collapse, I routed the foam tube from one vstack to the other and attached with zip ties or hose clamps. I figure it maximized filter area, and evened out “air box” vacuum.
Original post:
I am thinking that a foam tube could be bent (curved) and run from one intake to the other. To do this I had to order a flang-less type (pure foam) sock (I'll open up the closed end to make a tube). Given the stepped nature of the stock Eldo v-stacks I figured that a tube that was either 1.6 in × 6 in or 2 in × 8 in could be made to work. I ordered both (#'s U801 and U802), I'll let you know how they work out…
As it turns out either worked just fine. Only problem, the foam is an ugly green…
Follow-up
While I've not tried this solution, I think it would work very well.
A solution to the “catching fire” scenario would be to fit a mesh screen over each velocity stack before securing the filter. Dirt bikes routinely use this technique as a “flame arrestor” . I would use a stainless steel screen.
-
K&N part number RU-2450 -
This filter may be clamped directly to the velocity stacks that originally came on the Moto Guzzi V1000 I-Convert, V1000 G5, 1000 SP, and 850-T3 models (MG# 17114450). If using pod filters, this set up is my favorite. No permanent modifications are made to original Moto Guzzi parts, the fit is good, the clamp is secure, the important velocity stack is kept, and the slightly smaller physical size of the filter allows it to fit better in the available space.
The original velocity stacks for VHB carburetors (MG# 12114401) may be turned down on a lathe and made to work with this air filter.
Follow-up
This configuration is my absolute favorite.
I strongly recommend that the original velocity stacks NOT be modified.
-
K&N part number MG-2640 -
This is a single filter that is clamped directly to both velocity stacks that originally came on the Moto Guzzi V1000 I-Convert, V1000 G5, 1000 SP, and 850-T3 models (MG# 17114450). K&N lists this filter as a suitable replacement for the 1000 cc G5, SP, and I-Convert. Thanks to Paul Linn for bringing this alternative to my attention.
The original velocity stacks for VHB carburetors (MG# 12114401) may be turned down on a lathe and made to work with this air filter.
Follow-up
I strongly recommend that the original velocity stacks NOT be modified.
-
K&N part number R-0642 -
This filter must be clamped directly to the carburetor body…with the original velocity stacks for VHB carburetors (MG# 12114401) removed.
The original velocity stacks for VHB carburetors (MG# 12114401) or the velocity stacks from a V7 Sport or 850-T (MG# 14114401) may be turned down on a lathe and made to work (Thanks to Charlie Mullendore of Antietam Classic Cycle for sending me the information on modifying the velocity stacks).
Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
Follow-up
I have found that velocity stacks very much aid engine performance. I do not recommend removing the velocity stacks.
I strongly recommend that the original velocity stacks NOT be modified.
This is one of my least favorite solutions because it requires modification of original parts OR yields a performance compromise.
Amal carburetor information
Updated: 2005 Oct 05
Contributed by Joe Jump on the Yahoo! Loopframe_Guzzi news group.
Joe describes the Amal carburetors used on the late Eldorado models.
Those Amals are 930's - same stuff used on Nortons, BSAs and Triumphs post 1967-68. The numbers following the dash (after 930) defines the specifics with respect to main/idle jets, slide cut-away and needle taper/position. Don't worry about that - just replace hat you remove with the same parts which have individual IDs. The nylon screw that broke off in your hand is a bowl drain/main jet access screw. Parts for these are plentiful. There is a shop somewhere in Florida (Tampa area) called MAP (Made Across the Pond). They will have everything you would need. Do a Google search. And I'm sure you could find the parts in Daytona if you looked in the Yellow Pages.
I run 930s on my Norton. I had the carbs done by AMR in Arizona. Instead of sleeving the slide, they bored the body to accept Mikuni slides which are hard chrome plated brass. You loose the choke but I've found them to be unnecessary with the ticklers. I've put 20k miles on them and they still work great. Amal needle jets and needles are known to wear kinda fast - recommended replacement every 10k miles for precise metering.
One other thing to watch - the float hinge pin can vibrate (British twin) and actually wear an indentation into the bowl gasket. When this happens, the float can buzz around a bit more than normal and cause the fuel in the bowl to splash out through the tickler button and perhaps affect mixture too (too high of a fuel level in the bowl). I had this problem and resolved it by slightly pinching the tabs in the bowl adjacent to the float hinge pin to keep it captive in it's slot.
Lots of people curse Amals. They are simple units and once they are sorted with dissimilar metals between the body and the slide, updated with Viton tipped float needles, and the idle jet is opened up/cleaned (bread wrapper twist tie and Gummout spray works great for this), they work good and last a long time. Just my opinion.
Carburetor balancing/synchronizing
Updated: 2006 Jun 13
Contributed by Patrick Hayes on the Yahoo! Loopframe_Guzzi news group.
I presume you have the more common Dell'Orto square slide carbs. There are some early loops with round slide Amal carbs and these comments will be all wrong for them.
I presume you have plenty of slack in the “choke” cables so that they close fully and are NOT hanging off the end of the taut cables.
I presume you have vacuum tap ports on your intake manifolds. Again, early loops did not have these ports. They can be added easily. Later loops all had them.
I sure hope you have some form of vacuum measuring tool. Forget about doing it by ear, or feel, or counting rotations before stall, or sticking toothpicks in the carb throats. Those techniques are all horribly crude as related to vacuum measurement.
I hope you do not try to do this with analog gauges. It is impossible. It is far easier to read and far more intuitive if you use vertical column manometer vacuum measuring devices.
I like CarbStix the best, but they do have the danger of spilling toxic mercury. Mine are 25 years old and intact (tap wood). There are modern copies which use steel rods instead of mercury. That would be my choice if I were starting anew. There is an electronic TwinMax. Not as intuitive. But very small and portable as long as you learn how to read it. For about $2 you can make a tool out of fish tank air hose and ATF oil.
Get the bike running and warm and hook up the vacuum.
Begin by setting the idle speed. This is the big, exposed, knurled screw. DO NOT TURN THE SCREW!!! When the slides rest on the pointed tips of these screws there is a lot of contact load. You can damage the screw or the slide. Even for slight adjustments, always crack the throttle ever-so-slightly as you turn this screw so that it is not loaded while turning.
You probably will not have equal idle vacuum readings. They certainly won't be steady as they pulse up and down with each cylinder suction. You can visually and mentally average out where there center positions are. Whichever column is averaging lower, that side is open too far in relation to the other and that cylinder is working harder than the other. Depending on your idle speed, you can choose to slow down the harder working side (and its mercury column will now rise slightly on average) or you can open and accelerate the non working side. It doesn't matter if you choose to open one or close the other, you need to get them pulsing in average parallel. Remember to crack the throttle as you adjust this screw. Counterclockwise drops the slide, slows the cylinder, and raises the mercury column. Clockwise is opposite.
Once you have the idle speeds equal (showing equal pulsing vacuum) you can adjust the mixture. This is the smaller, recessed screw. Turn it inwards clockwise until you hear the motor stumble. Turn it outward counterclockwise until the stumble eases. Back out at least an additional 1⁄4 turn and maybe even 1⁄2 turn from this non-stumble point. You want the idles a little bit rich.
Go back and look at your idle speed balance as it may have been altered. Repeat the above two paragraphs.
Now to acceleration balance. Many will write to you about mid-range and high range balance. Hooey!! At big throttle openings and higher RPMs, your engine cannot possibly detect minor vacuum imbalances. The place where it is CRITICALLY important is at a stop light or traffic light when you are feathering the clutch and adding throttle to accelerate away. Cylinder imbalance is one of the biggest aggravators of the famous loopframe grabby clutch. It doesn't grab at 75 MPH, it grabs at 3 MPH when you are pulling away from a light.
If you did the above idle work accurately, the two carbs are drawing equally at idle and the two cylinders are producing equal power pulses. Now, when you open the throttle it becomes critically important that BOTH sides open and draw simultaneously and both cylinders increase their power output equally. Crack the throttle open. Not a WFO twist, just a 10% crack. Look at the vacuum columns. Just as you crack the throttle, one side suddenly drops or loses vacuum before the other. That side has a tighter cable and is starting to work harder first. Again, you can either loosen that cable or tighten the other.
The effect you want is two equally pulsing vacuum columns at idle and then they both drop simultaneously and equally as you begin to open the throttle. Everything else is superfluous.
You will never get perfection. You are talking lots of sliding parts in the carburetor and the cables and the throttle handle. Its all sloppy stuff and it will look a little different each time you blip the throttle. You will be amazed at how nicely the motor runs when it is in sync and how easily or quickly it goes out of sync. You will soon learn what it looks like to have these columns perfect and also what it looks like to have these columns close enough for everyday smooth operation without being fanatic about it.
Carburetor balancing/synchronizing without carb sticks
Updated: 2012 Jan 28
Even if you don't have mercury carb sticks, you can still do a pretty good job of synchronizing the carbs by hand (both of the following methods are performed with the engine off). And, since the factory didn't include bosses in the intake manifolds to which mercury carb stick could be attached, they expected (and provided explicit instructions in the manual) the carbs to be synced without them.
The factory recommendation
One method (recommended by the factory) is to put a thumb and a finger into each air inlet and feel when each slider starts to move when you very slowly open the throttle. The goal is to make both sliders open at exactly the same time.
John Schwartz's technique
An easier and more sensitive method is to create two 6 in straight pieces of wire. Place each wire in the air inlet with the end under the slider. The other end of each wire should come pretty close to meeting in the middle. Now, when you open the slider very slowly, you can simply view which wire moves first.
Charlie Mullendore's technique
Contributed by Charlie Mullendore of Antietam Classic Cycle on the Yahoo! Loopframe_Guzzi news group.
When there are no vacuum ports, I use drill bits of different sizes to synchronize the carbs.
- The air filter(s) will need to be removed.
- Engine not running.
- Pick a drill bit from your set that will just fit between the bottom of the carb throat and the bottom of the slide with the throttle released. Try the same bit on the other carb - if it won't slip in under the slide, adjust the (knurled) idle screw in until it does - if the bit fits too loosely, then adjust the idle screw out until it fits the same as the other carb.
- Now open the throttle slightly and use the friction screw on the twistgrip or other means to hold it there. Use a larger drill bit in the same manner as before to measure the opening height of the slides. If one is higher/lower than the other, use the cable adjuster on the top of the carb to adjust the slide up or down as needed.
- You may have to use the idle screws to adjust the idle speed up or down after this, just make sure you turn them the same amount.
- This will never be as accurate as syncing with a vacuum manometer.
Carburetor cleaning with boiling distilled water
Updated: 2012 Mar 30
Thanks to Rick Kaye for sending me this information in a private email. In Rick's own words:
Have you ever tried to put the disassembled carbs in boiling distilled water?
I did that with the honda carbs and was really impressed with how they got cleaned, no caustic material and really important was how they did not turn color and really looked new. Especially the petcock. I had to boil that twice as it was so plugged!
If you forget the fact that I need to get a set of micro drills to clean out the jets and such properly (silly me), this boiled water method really impressed me. And I just used brita filtered water, cheap aluminum serving pans and my gas grill. (better than inside as the wife would have killed me!!)
Just wanted your thoughts on this as the carb chem dip is pretty toxic to work with and discolors aluminum. And it really does not do any better cleaning job than the boiled water.
Carburetor cleaning with Pine-Sol
Updated: 2011 Dec 05
Thanks to Dana Larson and Charlie Mullendore of Antietam Classic Cycle for providing the following information on the Yahoo! Loopframe_Guzzi news group. In Charlie's own words:
Saw a mention of cleaning carbs with Pine-Sol on Thumpertalk, so thought I'd give it a try. Wednesday I poured two 48 ounce bottles (USD $3.32 each at my local market) into a 5 quart plastic container and submerged a pair of quite cruddy VHB bodies, bowls, etc. in it. This morning (Friday) I pulled the parts out and rinsed them off in hot water - beautifully clean!
One of the two bottles of Pine-Sol used to clean Moto Guzzi carburetors.Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
Moto Guzzi carburetors cleaned with Pine-Sol.Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
Moto Guzzi carburetors cleaned with Pine-Sol.Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
The Pine-Sol after cleaning two Moto Guzzi carburetors.Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
It's supposed to work better/faster if the Pine-Sol is warm (mine was in the 50° Fahrenheit shop), next time I'll bring the container in the house. It's only slightly darker after this pair, so I should be able to clean quite a few more.
Images provided by Dana Larson:
Before and after photos using a two day soak in Pine-Sol.Photo courtesy of Dana Larson.
Before and after photos using a two day soak in Pine-Sol.Photo courtesy of Dana Larson.
Before and after photos using a two day soak in Pine-Sol.Photo courtesy of Dana Larson.
Before and after photos using a two day soak in Pine-Sol.Photo courtesy of Dana Larson.
Some additional photos and information from Charlie Mullendore of Antietam Classic Cycle:
Did another set of carbs the other day. This pair was quite a bit cruddier — caked on goop covering more of the outside, though not as much white fluffy deposits inside. Only soaked these over night but the Pine-Sol was about 10° Fahrenheit warmer. Did the same excellent job, though I did need to scrub some of the more heavily soiled areas with a toothbrush a bit. If I had left them in for another day, that probably wouldn't have been necessary.
Before and after photos using an overnight soak in Pine-Sol.Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
Before and after photos using an overnight soak in Pine-Sol.Photo courtesy of Charlie Mullendore of Antietam Classic Cycle.
Carburetor float bowls - checking for leaks
Updated: 2008 Apr 25
Contributed by John Prusnek on the Yahoo! Loopframe_Guzzi news group. In John's own words:
Another way to test floats for leaks is to put them in the freezer overnight, then submerge them in a cup of hot water, look for bubbles as the air inside expands.
Carburetor rebuild - Dell'Orto VHB
Updated: 2012 Feb 29
This is a series of photos I took during the assembly of the carburetors on my I-Convert project bike. These are Dell'Orto VHB 30 carburetors. But, the procedure is 100% identical for Dell'Orto VHB 29 carburetors. Thanks to Charlie Mullendore of Antietam Classic Cycle, Robert Hawkes, Steve Farris, and Adam S. for making helpful suggestions for improvement.
It is a very good idea to work on one carburetor at a time. That way, you can refer to the assembled carburetor as a pattern.
Parts needed
Consumable parts I always replace:
Consumable parts I replace depending on condition:
- (2) Choke (enricher) plungers (these are cheap enough that I always have them on hand)
- (2) Float needles (these are cheap enough that I always have them on hand)
- (2) Floats (I order these if I need them. I do not replace unless I detect leaks in the originals.)
Disassembly
Disassembly is pretty much the reversal of assembly. So, just start from the last photo, and work your way up to the top.
Cleaning
Prior to these photos being taken, I had completely disassembled both carburetors and soaked all of the metal parts in a bucket of carb cleaner. With the parts out of the carb cleaner, I thoroughly rinsed them in a bucket of rubbing alcohol. Rubbing alcohol dries very quickly, leaves no residue, and - in my experience - does a good job of neutralizing the carb cleaner (though I'm not a chemist and haven't a clue whether or not alcohol neutralizes the carb cleaner, or simply dilutes it to a point where it doesn't matter). Use gasoline if you like, but I prefer rubbing alcohol. Even after cleaning, some of the brass parts appear discolored. Not to worry, they are clean and the discoloration really doesn't matter, as they will discolor again soon enough. But, if you like, a quick turn at a fine wire wheel (not coarse or heavy) will polish them up nicely. Just be cautious around the openings so that they are not enlarged and DO NOT WIRE WHEEL THE TAPERED NEEDLE AT ALL.
As an alternative, after soaking the parts in carburetor cleaner, Charlie Mullendore of Antietam Classic Cycle rinses them thoroughly in cold water, then hot water, and finally sprays through all of the passages with Berkebile 2+2 Gum Cutter.
Assembly
Clean the jets
Clean the passageways
Accelerator pump, atomizer, main jet
Note: Some prefer not to disassemble the accelerator pump piston; choosing instead to consider it perfectly functional if they hear the plastic ball bearing rattle inside the accelerator pump piston.
Idle jet
Choke (enricher) jet
I position the O-ring like this, and then push it over the top. I've found this method easier than trying to bring it up from the other end. Charlie Mullendore of Antietam Classic Cycle prefers to slip it up over the threaded end first, then work it over the larger end into the groove. Either way works fine. Charlie recommends using silicone spray lubricant on the O-ring to help it slip on easier.
Note: Gary Frankel sent me information about the simple tool he made to make installing this O-ring much easier. Check out his tool for installing the enricher jet O-ring on Dell'Orto carburetors.
Float, float needle, float pivot pin
Float bowl, float bowl nut
Idle speed screw
Mixture screw
Slide and tapered needle
Carburetor top and throttle return spring
Choke (enricher) assembly
Banjo fitting and filter
Carburetor return springs - lighter springs for Dell'Orto VHB
Updated: 2011 Aug 01
Please see the follow-up information at the bottom of this section.
There are good reasons not to put a lighter return spring inside your carburetor (e.g., the throttle may not fully returned to the closed position when you need it to). But, if you want to try a ligher return spring, Sean Fader of RTL Moto has mentioned the following on the Wildgoose Chase Moto Guzzi news group. In Sean's own words:
It's risky, and I absolutely don't recommend doing this, but Ace Hardware spring #182 will do the trick.
The manufacturer of the spring is Hillman.
Follow-up
Rick reports that the spring is too long and “coil binds” when the throttle is opened fully. This prevents the slide from being opened all the way up and prevents wide open throttle.
Carburetor - setting them up
Updated: 2008 Apr 25
Thanks to Charlie Mullendore of Antietam Classic Cycle for providing the following information on the Yahoo! Loopframe_Guzzi news group. In Charlie's own words:
I don't use the old “pull the plug wire off” method to set the carbs. Here's the (likely a bit backasswards) way I do it instead:
If you don't have vacuum ports to hook some sort of balancing device to, you'll need to remove the airbox and sync. the carbs by measuring the height of the slides (from the bottom of the slide to the base of the carb throat). You can use drill bits or other similar objects as measuring tools.
As a “base setting” , I usually adjust the throttle stop screws (on the square area of the carb body) until there's an approx. 10mm wide (semi-circular) opening showing at the front (towards the engine) of the slide when I look into the carb throat. Measure the slide height at the back (towards the filter) with a drill bit and set both carbs the same.
Make sure you have a little (3 mm or so) slack in the throttle cables where they go into the carb. top. If your throttle twistgrip has a “friction screw” that you can turn in to hold the throttle open, turn it in to do just that. Or if not, figure some other means of holding the throttle open (assistant, duct tape, etc.). Open the throttle slightly and acting on the cable adjusters on the carbs tops, set both slides to the same height. Make sure you still have slack afterwards.
Turn the idle mixture screw (small screw, recessed into the carb body, near the float bowl)in until it seats lightly and then back the left one out 11⁄2 turns and the right one out 13⁄4 turns.
Release the throttle holding device, start the engine and let it warm up. If it's idling too high, turn each throttle stop screw out an eighth of a turn. If too low, turn them in an eighth of a turn each. Try to turn them in or out precisely the same amount to avoid disturbing the balance you set earlier. Next turn each idle mixture screw in until the engine speed drops (listen carefully as it can sometimes be difficult to tell) and then back it out 1⁄2 turn. If necessary, adjust the throttle stop screws again to achieve the desired idle speed.
Alrighty then. Clear as mud? Best job I can do right now with only 5 hours of sleep last night and after doing some sort of weird triathlon today (ride 4.5 hrs./200 miles to lunch in Keysville, VA, ride 5 hrs./210 miles home, push mow grass for an hour!).
Carburetor - single manifold
Updated: 2012 Apr 26
Calculating the needed size of a single carburetor
Thanks to Mike Tiberio for posting this information on the Yahoo! MGconvert news group.
To figure out how big a carb you want, calculate the cross sectional area of a 32 mm carb (PI × R2), multiply by 2, and calculate from that the diameter of a single carb that could give you the same area…
A 44 mm carb has the same cross sectional area as two 32 mm carbs.
Sonny Angel setup
Photo courtesy of John Boettcher.
Max setup
Thanks to John Engle for sending me these photos and information in a private email.
Photo courtesy of John Engle.
Photo courtesy of John Engle.
Unknown setup
Thanks to Tom Short for provided these pictures.
Photo courtesy of Tom Short.
Photo courtesy of Tom Short.
Photo courtesy of Tom Short.
Photo courtesy of Tom Short.
Photo courtesy of Tom Short.
Dell'Orto PHF 30 carburetor fitment
Updated: 2011 Mar 22
Dell'Orto PHF 30 carburetors were never fit by the factory to the Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models. All the same, it is possible to do so.
I extracted this information from Steve Odell off of the Yahoo! Loopframe_Guzzi newsgroup. In Steve's own words:
Almost done. Waiting on a few parts from Dell'Orto UK and then fire it up. Just because I know everyone will ask; no, the sidecovers will not go on for either side. Even V700 covers, which I have, will not make it. A minor problem. New manifolds being machined and welded up now to give a bigger turn in, 15° or so, and then refit the stock covers.
But, at the moment I want to be on the road now, not later. Just have to finish the carb setup and tuning, bolt up the dual 40 mm Brembo disks setup (GuzziTech adaptors and Ducati 900CR calipers) and install the newly painted fenders I just got back from Steve Hill.
I threw on an old tank I have with cubes on it. As you can see there is plenty of clearance. But will there be clearance when I angle them in another 15 degrees or so to fit sidecovers? I think so as the vertical clearance seems to be enough with the handle down even if they were one on top of the other. If anything you may have to point your cubes in a direction other than what you are familiar with to get the handle out of the way of the cable.
Also, while the set of VHB's I built were well suited for my bike one of the reasons I went to PHF is the lack of VHB parts. Needles for example. Nothing controls your engine's response more than the needle. For VHB's you have two choices, V5 if you can find a good one, or V9 which is what I ran. On the PHF's I have 95 needle choices, K1 all the ways through K95. All readily available new.
The second reason is the far superior PHF accelerator pump. The VHB pump is a joke, a little dribble of gas into the venturi. The PHF will shoot a jetstream of gas across the room (I've done it). There is just no comparison.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
Dell'Orto PHF 30 carburetor fitment on a Moto Guzzi Eldorado.
Photo courtesy of Steve Odell.
O-ring for sealing the carburetor enricher cable holder
Updated: 2009 Jul 20
On some VHB carbs (certainly not all), the aluminum holders for the enricher cables have a groove to accept a small o-ring. The purpose of this O-ring is to prevent foreign material (e.g., rain) from entering the carburetor. This size of this O-ring is 1 mm wide with an inside diameter of 8 mm and an outside diameter of 10 mm. Thanks to Jon Sefcek for sending me this information in a private communication.
Intake manifolds
Updated: 2010 Feb 10
VHB Carburetors
The intake manifolds are not the same for each side. Since the cylinders are in different positions on the crankshaft, the intake manifolds are slightly different in order to partially compensate for this positioning difference (the rubber boot that connects the velocity stacks to the air box take up the remaining difference). These photos should make it pretty clear which side is which. “S” markings mount on the left side of the motorcycle, “D” markings mount on the right side of the motorcycle.
Pinging
Updated: 2005 Oct 04
Contributed by Patrick Hayes on the Yahoo! Loopframe_Guzzi news group.
First lets understand what a “ping” is. The compressed air/fuel mixture in your cylinder does not “explode” . Rather, it burns at a very fast rate. The flame starts at the tip of the spark plug and progresses outward, like ripples in a pond, until it reaches the cylinder walls and consumes all of the mixture. This progressive flame can be measured and seen. A famous Dr. Diesel put glass windows into cylinder heads about 110 years ago to confirm this. The ripples of pressure ahead of the flame wave cause the mixture to get a little more compressed than just the cylinder compression. Increase it enough, and the remaining mixture spontaneously and completely “explodes” by adiabatic pressure, ahead of the intended flame front. This can be heard as a “ping” . Generates lots of instant heat and can melt aluminum. Any of that in your motor? It creates a snowball effect. The pinging makes the engine hotter. The engine pre-heats the air/fuel mixture a little more before it is sparked. Once sparked, the the pre-heated mixture burns more rapidly than the engineer intended it to. It pings and generates more heat again.
The ignition timing curve is designed to allow the flame front to propagate smoothly so that the piston is already starting down and relieving pressure as the flame reaches maximum internal pressure. That's fine on the drawing board. You can do a lot of things to screw up the design.
The progress of the flame is also partially controlled by the nature of the fuel. Premium or Hi Test fuel is designed to burn more slowly so that the flame front is not effected quite so much by high compression motors. Contrary to popular opinion, regular fuel burns faster than premium fuel.
Are you burning “regular” fuel? Don't do it.
Realize that the ignition timing was designed in the 60's when we could buy 96 octane fuel. Now the best we have is 91. So, the designed ignition timing is too far advanced for the modern fuel. Try backing off the timing by 1° or 2°. You may sacrifice a little performance, but you have to adapt your old motor to the modern fuel reality.
Probably the worst condition for pinging is to contaminate the air/fuel mixture with oil. Minuscule amounts of oil. Far less than you could measure or see burn as smoke. Guzzis have no seals on the valve guides. After a period of wear, they start to bleed some oil past the intake valve stem on suction. Suddenly, your expensive 91 Premium fuel is probably burning at an equivalent of 84 cheapo regular. Ping. When was the last time you did a complete valve job and exchanged the guides and/or valves. My bet is that 40K miles is about the life limit with about the last half of that life passing excess oil.
Separating the carburetor from the intake manifold
Updated: 2011 Oct 21
Thanks to Charlie Mullendore of Antietam Classic Cycle for providing the following information on the Yahoo! Loopframe_Guzzi news group. In Charlie's own words:
As others have mentioned, twisting and pulling at the same time is how they normally come off. Unfortuntely, there's not a lot of room to work without crushing your fingers (ouch!). In the most extremely stuck cases, I do one of two things:
- Remove the carb with manifold, bolt them to a spare junk head held in my bench vise and then do the twist and shout…er, pull. Still, they're a pain to remove.
- Alternatively, use a block of wood (my choice is white pine 2 in × 2 in, 10 in long) to drive them off of the manifold. Butt the end of the 2 in × 2 in up against the forward end of the carb where the manifold goes in (never the square area or the bowl!), use a hammer to whack the 2 in × 2 in, drive first on the top and then underneath, alternating to keep the carb coming off straight back. (Thanks to Mike Tiberio for this tip).
Before installing, make sure the manifold is free of burrs, corrosion, etc. by dressing the area the carb slips up onto with Scotchbrite. Likewise, make sure the plastic sleeve in the carb isn't cracked, burred or deformed — it can be lightly dressed with sandpaper if needed. Coat the plastic sleeve of the carb lightly with anti-seize, same with the manifold. Carb should slip on a lot more easily, wipe off any excess anti-seize.
