The V700 and early Ambassador models came with the shifter on the right side and the rear brake on the left side...similar to many British bikes of the same era. With the standardization to left side shift and right side brake, some owners - for a variety of reasons - prefer to change the orginal set up to the now standard configuration. While I am not a proponent of such changes, here is how to do it.

Frame modification

On the left side of the frame there is already a tube through which the current left side brake rotates. This is exactly the same thing that is used on the later models. So, you have no need to modify it at all.
On the right side, all you'll need to do is create a mate to the tube on the left side. There are some differences...
- On the left side, should you care to take measurements, you'll find that the tube has an ID = 14 mm and a length = 57 mm.
- On the right side, however, the tube has an ID = 16 mm and a length of 35 mm.
Inside measurement: The distance from the right side of the left tube to the left side of the right tube is 202 mm.
Outside measurement: The distance from the left side of the left tube to the right side of the right tube is 294 mm.

You'll have to position the right side tube carefully so that the center of the 14mm and 16mm tubes are the same in all planes. For me, anyway, that would be the tricky part of this whole operation.

One thing I will mention. It appears that the later Ambassador and Eldorado brake tubes are positioned ever so slightly forward of the V700 and early Ambassador brake tube. Upon close scrutiny, I can find no reason to cut off the existing tube only to move it forward a wee bit. I believe everything will fit just fine, but I did want to mention this.

Parts needed

Now, on to the pieces and parts you'll need to find. Have a look at the Ambassador spare parts catalog I have posted on my website (2nd edition, the one that has 81 pages)

For the rear brake, take a look at Tavola 16 (Plate 16). What you need are diagram numbers 38, 39, 40, and 42. Diagram numbers 36, 37, 41, 43, 44, 45, and 46 are just generic nuts, bolts, split pins, and snap rings. Nothing you probably don't already have or can easily pick up at any local hardware store. You may not need part 38. But get one anyway just in case part number 59 doesn't fit.
For the shift lever, take a look at Tavola 9 (Plate 9). What you need are diagram numbers 10, 61, 62, 13, and 20. The remaining parts are mundane things you already have or can easily get. Diagram number 20 is something you can get if you want to. But, I would recommend replacing it with two Heim joints and a threaded rod linkage. Have a look at what I did to my shift linkage...I consider it a fantastic improvement over the original.
Diagram numbers 61 and 62 are plastic bushings...one fits inside the other and then the both fit inside the left foot peg (I'll get to it in a moment). I've got measurements of these on my website: shift linkage bushings, but try to get the originals if you can.
You will also need another bushing...more rubber-like than plastic, that fits over the right end of diagram number 13 and inside the transmission. This part isn't listed in the Ambassador spare parts catalog, but it is listed in the Eldorado spare parts catalog. I do have the measurements on my website under the same shift linkage bushings section.
Finally, you'll need another left foot peg. Take a look at Tavola 11 (Plate 11). You'll need diagram number 39.

Neutral indicator switch

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Removal and replacement

The neutral indicator has a curve/bend at one end. When installing the indicator, the curved/bent portion of the indicator should point down.

As an alternative, the indicator can be installed with the bend facing up. Then, take care to adjust the bend so that it just makes contact with the nub on the shift drum. Doing so will make the neutral indicator light much more precise. Greg Field provided this tip.

Oil tray and passages - 4 speed transmissions

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Thanks to excellent mechanic Sean Fader of Moto Guzzi Classics who posted this information on the Yahoo! Loopframe_Guzzi news group. In Sean's own words:

Yeah guys, the tray funnels gear oil (that is flung up into it) into a passageway in the front of the case. That passageway leads into the area behind the cone washer, then into the shaft center. Make sure the tray is clean and also that the passageway is not blocked. Blow thru it with air if possible.

When installing the tray, the end with the diagonal bend in the edge goes at the rear of the transmission...nearest the rear cover.

Shift linkage

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Sloppy linkage fixes

The shift linkage on my 4 speed, left side shift transmission was getting very sloppy. With time and use, the clevis pins simply elongate the holes and slop is the result...at least an inch at the shifter in my case.

I've heard of three different fixes:

Find the next larger size clevis pin (either inch or metric) and drill out the holes to accept this new larger size. It is also recommended that the hole be drilled slightly smaller, then reamed to a precise fit. Thanks to Mark Etheridge of Moto Guzzi Classics and Guy Winton for this tip.
Purchase bushings and custom fit them to take up the space between the smaller clevis pin and the larger hole. This may also require drilling. Thanks to John Ulrich for this tip.
Replace the entire setup with Heim joints (also known as ball end joints). I chose this approach because it required the least amount of work and promised the tightest joints over the long-haul. It does, however, yield an appearance that is not stock. Thanks to Ron Komoroski and Rob Prins for this tip.

Here is where I sourced the parts:
- Metric 6 mm x 1 mm female Heim joints: McMaster-Carr item number 6275K53.
- Metric 6 mm x 1 mm x 95 mm black-oxide steel stud: McMaster-Carr item number 93275A020. I painted this a dull silver color to help protect against corrosion.
- Bruce Henshaw informed me of another great place to source these parts: Midwest Control Products
- You may also be able to locate these materials through a local semi truck dealer, as apparently many trucks use these joints, too.
Outcome: I have absolutely no slop left in my shift linkage!

Additional notes

I gave up on the shift offset bracket. The clearances were so tight around the shift arm, that I couldn't get the adjustment I needed for the clutch to disengage properly (see photos below). I'm certain that it works great on the Eldo 5 speed...but things are just too tight on the left side of the 4 speed.

Whilst beginning a ride with the local classic owner's group, my shift linkage broke. I had bent the stainless allthread to clear the shift lever. You guessed it, it broke right at the bend. So, I snuck her into 2nd gear and headed for home, grabbed the Quota, and met up with the guys in time for breakfast.

Back home for the fix, I really wanted to continue using my Heim joints and allthread (this time leaving the allthread linkage unbent). So, I scavenged a straight 4 speed shift arm to replace my dog-legged shift arm and found the clearances I needed. These are the little arms that attach directly to the shaft exiting the rear of the transmission (see photos below) - I didn't even know that Guzzi made more than one kind.

Along the way, I took the time to notice the movement of stock lower shift arm (this is the arm that is welded to the shaft that connects directly to the foot operated shift lever). Low and behold, if the linkage is too short, the lower shift arm will hit a cover bolt on the up-stroke. I made sure this had ample clearance and put everything back together.

From the worn spot on the arm and a contact spot on the case bolt (see photos below) I'm just certain that the extra-bend in the linkage was causing the welded arm to hit the case bolt before it travelling as far as it needed to go...thus shortening my up-stroke and making it difficult to shift.

The end result is that I'm mostly satisfied with my shift linkage. My only improvement now will be to source a proper rod to replace my temporary allthread solution.

Follow-up: Now that I'm using the 95 mm rod in place of the allthread, I am completely satisfied with my shift linkage. I works properly and has very little play. I love it when a plan comes together!

Shift linkage bushings

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There are three plastic bushings that are used in the shift linkage on my 4-speed, left side shift transmission. Here are the specifications for these bushings:

Large outer bushing that fits inside the foot peg (MG# 12442105): ID: 20 mm, OD: 26 mm, Width: 20 mm

A suitable replacment is available from McMaster-Carr, item number 7811K46. It is made out of bronze, rather than hard plastic.
Small inner bushing that fits inside the large outer bushing in the foot peg (MG# 12441905): ID: 16 mm, OD: 20 mm, Width: 20 mm

A suitable replacment is available from McMaster-Carr, item number 7811K33. It is made out of bronze, rather than hard plastic.
Small bushing that fits inside the transmission housing, accepting one end of the shift shaft (MG# 12200900): ID: 14 mm, OD: 18 mm, Width: 8 mm

A suitable replacment is available from McMaster-Carr, item number 7811K23. It is made out of bronze, rather than hard plastic. It does not come in the exact width needed, but the item number provided is long enough to cut in half and make two.

Note: After replacing my plastic bushings with bronze bushings, I found my shift shaft was binding. I left the bronze bushing embedded within the transmission housing and switched back to the plastic bushings. No more binding. Apparently the system needs some slop...or at least mine did.

Speedometer drive gear

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Description

The speedometer drive gear is a shaft that contains a worm gear. The square speedometer cable slides into the shaft at one end of the gear. The other end of the gear (the portion that contains the worm gear) fits into the transmission.

Removal and replacement

Extreme caution must be exercised whenever the speedometer drive gear is removed. A special washer is located on either side of the worm gear. The purpose of these two washers is to prevent undo wear as the drive gear rotates. It is easy to retrieve the washer on the top end of the worm gear...it comes out when the worm gear is removed. The washer on the bottom end of the worm gear does not come out automatically. If you are not careful, it is possible for this washer to become dislodged and fall into the transmission...ruining parts that you do not want to ruin. So, using a magnet, needle nose pliers, long slender pick, or similar object, carefully remove the lower washer. When reinstalling the speedometer drive gear, adhere the washer to the worm gear with a dab of grease.

Throw-out bearing cross-references

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The throw-out bearing used on Eldorado and all but the earliest Ambassador models is ID: 10 mm, OD: 22 mm, Width: 3 mm. I have sourced a suitable needle bearing replacement. No, it isn't metric. But it is cheap and it works.

22 mm size

IMPORTANT NOTE: If the inner body of your throw out assembly has a protrusion that must slide through the inner diameter of the bearing, then this bearing will not work for you. Please check before ordering as some will work and some will not.

Thrust bearing; Torrington NTA-613: 0.3750" ID x 0.8125" OD x 0.0781" Width; Motion Industries item number 00094466
Thrust race (2 may be necessary); Torrington TRA-613: 0.3750" ID x 0.8125" OD x 0.03" Width; Motion Industries item number 00094559

20 mm size

The throw-out bearing used on V700 and the earliest Ambassador models is ID: 10 mm, OD: 20 mm, Width: 3 mm. I have sourced a suitable needle bearing replacement. No, it isn't metric. But it is cheap, it works, and it doesn't involve removing the transmission so the case can be bored for the commonly available larger bearing.

Thrust bearing; Torrington NTA-512: 0.3125" ID x 0.75" OD x 0.0781" Width; Motion Industries item number 00094462
Thrust race (2 may be necessary); Torrington TRA-512: 0.3125" ID x 0.75" OD x 0.03" Width; Motion Industries item number 00094556

Transmission (and engine) removal

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The technique I use is described in the "Engine, clutch, & related components" section: Engine (and transmission) removal

Transmission bearing cross-references - 4 speeds

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All are of the standard ball bearing type except where otherwise noted; all are open (not shielded or sealed).

Note: I have visually verified all of the bearing sizes for the 4 speed transmission.

Input / clutch shaft

Front of transmission (MG# 92201225):
- 25 mm ID x 52 mm OD x 15 mm thick
  - Maryland Metric item no. 6205 Premium
  - McMaster-Carr item no. 5972K106
  - Motion Industries item no. 00052513
  - FAF 205K
  - FAG 6205
  - FED 1205
  - MRC 205-S
  - ND 3205
  - New Departure 3205
  - NH 205
  - RIV 2A 25
  - SKF 6205
  - STEYR 6205
Rear of transmission (MG# 92201120):
- 20 mm ID x 42 mm OD x 12 mm thick
  - Maryland Metric item no. 6004 Premium
  - Motion Industries item no. 00047827
  - FAF 9104K
  - FAG 6004
  - FED 9104
  - MRC 104-KS
  - ND 3L04
  - New Departure 3L04
  - NH 6104
  - RIV ELL 20
  - SKF 6004
  - STEYR 6004

Cluster / main shaft

Front of transmission (MG# 92256217):
- 17 mm ID x 35 mm OD x 15 mm thick - this is a needle bearing
  - Durkopp 10-2762
  - RIV NAS 17
  - Torrington 10-2762
  - Timken 10-2762
Rear of transmission (MG# 92201220):
- 20 mm ID x 47 mm OD x 14 mm thick
  - Maryland Metric item no. 6204 Premium
  - McMaster-Carr item no. 5972K105
  - Motion Industries item no. 00052158
  - FAF 204K
  - FAG 6204
  - FED 1204
  - MRC 204-S
  - ND 3204
  - New Departure 3204
  - NH 204
  - RIV 1A 20
  - SKF 6204
  - STEYR 6204

Output / lay shaft

Front of transmission (MG# 92201220):
- 20 mm ID x 47 mm OD x 14 mm thick
  - Maryland Metric item no. 6204 Premium
  - McMaster-Carr item no. 5972K105
  - Motion Industries item no. 00052158
  - FAF 204K
  - FAG 6204
  - FED 1204
  - MRC 204-S
  - ND 3204
  - New Departure 3204
  - NH 204
  - RIV 1A 20
  - SKF 6204
  - STEYR 6204
Rear of transmission (MG# 92201222):
- 22 mm ID x 50 mm OD x 14 mm thick
  - Maryland Metric item no. 62/22
  - Motion Industries item no. 00040272
  - FAG 62/22
  - RIV 1A 22
  - SKF 62/22
  - STEYR 62/22

Transmission bearing cross-references - 5 speeds

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All are of the standard ball bearing type except where otherwise noted; all are open (not shielded or sealed).

Note: I have visually verified all of the bearing sizes for the 5 speed transmission.

Input/clutch shaft

Front of transmission (MG# 92218424):
- 25 mm ID x 52 mm OD x 20.6 mm thick - this is a double row ball bearing
  - FAG 3205
  - FED 5205
  - ND 5205
  - New Departure 5205
  - RIV 3205 or 2AANOn25
  - SKF 5205
  - SKF (Eur.) 3205
  - STEYR 3205
Rear of transmission (MG# 92256218):
- 17 mm ID x 35 mm OD x 15 mm thick - this is a needle bearing
  - Durkopp 10-2762
  - RIV NAS 17
  - Torrington 10-2762
  - Timken 10-2762

Main/cluster shaft

Front of transmission (MG# 92256218):
- 17 mm ID x 35 mm OD x 15 mm thick - this is a needle bearing
  - Durkopp 10-2762
  - RIV NAS 17
  - Torrington 10-2762
  - Timken 10-2762
Rear of transmission (MG# 92201417):
- 17 mm ID x 17 mm OD x 14 mm thick
  - FAF 303K
  - FAG 6303
  - FED 1303
  - MRC 303-S
  - ND 3303
  - New Departure 3303
  - NH 303
  - RIV 4B or 6303
  - SKF 6303
  - STEYR 6303

Lay/output shaft

Front of transmission (MG# 92234117):
- 17 mm ID x 47 mm OD x 14 mm thick - this is a cylindrical roller bearing
  - FAG NF 303
  - HOFF R 317 L
  - RIV FN 303
  - SKF (Eur.) NF 303
  - STEYR NF 303
Rear of transmission (MG# 92218424):
- 25 mm ID x 52 mm OD x 20.6 mm thick - this is a double row ball bearing
  - FAG 3205
  - FED 5205
  - ND 5205
  - New Departure 5205
  - RIV 3205 or 2AANOn25
  - SKF 5205
  - SKF (Eur.) 3205
  - STEYR 3205

Transmission - false neutrals

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False neutrals are "normal". However, they can be reduced in a few ways.

Properly adjust the clutch cable...starting at the lever at the back of the transmission and moving forward to the handlebar lever. Always maintain the proper amount of free play at the hand lever (1/8" as specified in the manuals).
Eliminate slop in the shift linkage. A little slop translates into a loss of movement of shift dogs inside the transmission. Check out the Shift linkage section for a few ways to eliminate it.
Shift properly. There is a technique that must be used. Check out the Transmission - shifting technique section to learn the technique.
Shim the shift drum. This is best done when you have the transmission out for other reasons. No need to bother with this unless things get really bad. Check out the Transmission - Shimming the shift drum section for some info on the subject.

Transmission - Installing the small triangle shaped rear selector cover plate on a 4 speed transmission

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This tip came from John Schwartz. When installing the small triangle shaped rear cover plate, set it in loose and check the 5 bolt holes that secure the selector cover. If they don't line up true, loosen the 19 mm lock nut on the adjusting screw and rotate as required to line the bolt holes up. This insures that the shift lever may stroke in both directions when shifting.

Transmission leaks - a fix for the four speed layshaft (output shaft)

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The four speed transmission layshaft (output shaft) is sealed using a typical oil seal. The oil seal is pressed into the rear cover of the transmission and seals against the outside diameter of a metal ring that slides onto the output shaft. In front of the metal ring is the speedometer worm drive gear, then a shimming washer, then the rear bearing for the layshaft (output shaft). There is no means (other than by metal-to-metal contact) by which to prevent gear oil from escaping from between the layshaft (output shaft) and the metal ring. To further complicate matters, there is a square key-way that runs the from the rear of the layshaft up to the bearing.

If the matting surfaces of all the components are in perfect condition, the 150 foot pounds of torque required to secure the ring nut would probably be sufficient to prevent oil from escaping. But if the surfaces are less than perfect - as is typical of 35 year old parts - problems can arise.

It would seem that a 2-pronged approach would alleviate this problem:

Mill a small recess on one end of the metal ring to accept an o-ring. The o-ring will compress against the speedometer worm-drive gear.
Fit a slightly-oversized square o-ring into the square key-way, compressing it in place with the metal ring.

Note

I have not yet attempted this modification...but I'm about to. I will report back here after I've had a chance to fully evaluate the results.

Transmission leaks - a fix for the four speed pre-selector shaft

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Of the very few drawbacks unique to four speed transmissions, perhaps the most annoying is the oil that leaks from the pre-selector shaft. Five speed transmissions have an o-ring to prevent such leaks. But the mighty four speed was not so blessed. Having heard of other owner's who had an o-ring recess machined in the small triangle cover, I decided to do the same. I had my favorite machinist, Pistol Pete, machine the recess for me. I chose to use the standard 5-speed pre-selector shaft o-ring (MG# 90706140). Here are photos of the outcome.

Follow-up

I've had the o-ring installed for many thousands of miles now and it has done a very good job of preventing oil from escaping through the pre-selector shaft. I consider it a very worthwhile modification.

Transmission out? Check these things

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If you've gone to all the trouble to remove the transmission from your bike, you might as well check and replace as necessary the following items (it sure beats taking the transmission out again).

Clutch shaft (input shaft) seal.
Layshaft (output shaft) seal.
On four speed transmissions, replace both cover gaskets if disturbed (MG# 12201100 and MG# 12201500).
On five speed transmissions, replace the single cover gasket if disturbed (MG# 14201110).
On five speed transmissions, replace the o-ring that seals the pre-selector shaft (MG# 90706140).
On five speed transmissions, replace both o-rings beneath the clutch input hub (MG# 90706203 and MG# 90706235).
Replace the o-ring for the outer body of the throw-out bearing assembly (MG# 90706170).
Replace the pushrod seals. Moto International sells a clutch pushrod seal kit MG# 14085900. It's a handful of small o-rings (5 or 6) that go down the hole in the input/clutch shaft to keep oil from leaking out the front of the shaft and into the clutch (MG# 12085901).
Replace all of the crush washers (for the fill, drain, level-fill, and the plug for the selector pawl). I prefer fiber washers for the drain and level plugs because they require less force to crush and prevent leaks (and thus less chance of stripping the delicate threads).

Transmission - pre-selector shaft rotation

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Originally, both the 4-speed and 5-speed transmissions (as used on the loops) used a 1-up, 3- or 4-down shift pattern (using only the toe of the shift lever - ignore the heel). If you look at the rear of the transmission, the lever on the pre-selector shaft always pointed toward 3 o'clock to achieve this shift pattern.

If you remove the lever from the pre-selector shaft and rotate it into the 9 o'clock position, the shift pattern will be reversed (1-down, 3 or 4 up).

In other words:

clockwise rotation of the preselector shaft down shifts
counter-clockwise rotation of the preselector shaft up shifts

All this being said...it is possible that a different shift drum has been fitted inside the transmission and that can flip-flop everything I've just said.

Transmission - Proper shaft alignment for assembly of a 4 speed transmission

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This tip came from John Schwartz. When reassembling a four speed transmission, it is absolutely necessary to properly align the gears. If the gears are not properly aligned, the four speed transmission will magically turn into a two speed transmission (you will be able to get first and second gears OR third and fourth gears, but not all four. Fortunately, John Schwartz sent me a diagram showing precisely how everything must be aligned before putting on the rear plate.

This drawing shows the proper alignment of the shafts when assembling a four speed transmissionThis drawing shows the proper alignment of the shafts when assembling a four speed transmission

Transmission - reversing the shift pattern by moving the shift arm

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Thanks to Neil Dilly who posted this information on the Yahoo! Loopframe_Guzzi news group. In Neill's own words:

You might remember I mentioned changing to a 1 down 4 up pattern. This is what we ended up with, modified gearshaft at top of pic.

The gearchange shaft has new bushes at both ends, so with the rose/heim joints at each end, hopefully thats taken care of the sloppage!

Transmission - reversing the shift pattern by using a Shift Offset Bracket

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Bolts on without having to remove shifter shaft. Easy adjustment and alignment.

Allows 1 down, 2-5/2-4 up shift pattern on Eldorados and Ambassadors.

Stephen Brenton is kind enough to manufacture this bracket. Contact him directly for price and availability.

Transmission ring nuts / lock nuts / spanner nuts / prong nuts / retaining nuts / lock rings

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The four speed transmission layshaft (output shaft) and the five speed transmission clutch shaft (input shaft) share the same ring nut (MG# 93601022). This ring nut is 22 mm x 1 mm and is 7 mm tall. The same threads (22 mm x 1 mm) are used on the layshaft (output shaft) of the five speed transmissions...only in a special hex nut that is 12 mm tall (MG# 14219310).

It is rumored that the hex nut can be used in place of the ring nut.

Thanks to Tom Halchuk for sending me information on sourcing these parts.

The Whittet-Higgins Company manufactures ring nuts and special locking washers of the proper dimensions.

Original size: 22 mm x 1 mm
Whittet-Higgins Retaining nuts (KM-044 or KMM-044)
Whittet-Higgins Lock washers (MB-044 or MBA-044)

Transmission seal cross-references - 4 speeds

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There are two seals used on the 4 speed transmissions:

Cluch shaft (input shaft) (25 mm ID x 35 mm OD x 7 mm Width)
Layshaft (output shaft) (35 mm ID x 47 mm OD x 7 mm Width)

Transmission seal cross-references - 5 speeds

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There are two identical seals used on the 5 speed transmissions, one for the clutch shaft (input shaft) and one for the layshaft (output shaft). Often times a dual lip Viton seal is used on the layshaft (output shaft) while a single lip seal is used on the clutch shaft (input shaft).

Cluch shaft (input shaft) and layshaft (output shaft) (35 mm ID x 47 mm OD x 7 mm Width)

Transmission shift hole fill plugs

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Contributed by Ray Hale on the old Topica Loopframe_Guzzi news group (which has now moved to Yahoo!).

I needed to replace the rubber plug on the starboard side of the Eldo trans box plus fill the hole on the port side where the shift linkage used to go before I switched to floorboards. Took the old beat-up plug to Lowes and found the following which fit perfectly, after carving a bunch off the length:

Hillman rubber stopper 3/4 x 9/16 x 1

Transmission - shifting technique

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Proper shifting technique is critical to enjoying a loop frame. Do it wrong and you'll constantly be frustrated by the transmission. Learn and practice the proper technique and horizons of pleasure will open up unto you! Here are the basic steps:

Disengage the clutch (pull the handlebar lever in).
Move the shift lever in the direction you want it to go and hold it there. Do not let up. There is no need to "jab" or "jam" or "hit". Just push it into place. It may or may not engage, but don't worry about that right now. Just hold the shift lever in place.
Engage the clutch (release the handlebar lever). You may feel the transmission hook up right away...or you may feel your shift lever move a little further and then feel the transmission hook up. Either result is fine. By keeping your foot on the shift lever, you are keeping pressure on the shift dogs until they have had a chance to engage with the corresponding cogs on the gears.
Remove your foot from the shift lever.

This technique will go a long way toward easing shifting troubles. There is no danger of excessive wear on the shift components by doing this...unless, of course, you choose to ride around with your foot on the shift lever for extended periods of time. The reason this technique works is that it working with the mechanical forces inside the transmission. We do not have "tap-your-toe", "snick-snick-snick" transmissions...but they generally work very well and are relatively heavy duty.

Transmission shift return spring - Installing a 5 speed shift return spring on a 4 speed transmission

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I prefer to use the traditional 5 speed shift return springs on the 4 speed transmission. I think they have greater strength. They do, however, fit differently than the standard 4 speed shift return spring. This diagram shows how to fit a 5 speed shift return spring on a 4 speed transmission.

This drawing shows the proper way to install a 5 speed shift return spring on a 4 speed transmissionThis drawing shows the proper way to install a 5 speed shift return spring on a 4 speed transmission

Transmission - Shimming the shift drum

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Shim the shift drum

This sounded scary and difficult to me at first, but it turned out very easy to do (especially with some help from John Ulrich on a cold Minnesota Saturday at the end of January, 2004). And the results are great: fewer false neutrals, reduced clunking when shifting, less shift pedal movement required to engage gears, etc.

Thinking - Myself and John UlrichThinking - Myself and John Ulrich

More thinking - Myself and John UlrichMore thinking - Myself and John Ulrich

Horsing around - John Ulrich and myselfHorsing around - John Ulrich and myself

Finally a little work gets done - John turns the clutch input hub while I shift through the gearsFinally a little work gets done - John turns the clutch input hub while I shift through the gears

For materials, you'll just need a supply of shims...they come in the following sizes: .6 mm (MG# 55235000), .8 mm (MG# 55235001), 1 mm (MG# 55235002), and 1.2 mm (MG# 55235003). The shims are cheap, so I got two of each and now have plenty of extras. The outside diameter of the shims is 22 mm and the inside diameter is 8 mm. But none of these dimensions are critical. A selection of inch shims with an inside diameter of 5/16" and an outside diameter of 3/4", 7/8", or 1" would work well, too (using thicknesses of .020", .030", .040", and .050").

5 speed shimming procedure. I suggest reading these articles from the GuzziTech web site:
4 speed shimming procedure - this is very similar to the 5 speed shimming procedure (so start by reading the articles above), but since I was unable to locate any instructions specifically for the nuances of 4 speeds, here they are:
- One shim should be located at the front of the shift drum, between the shift drum and the case (MG# 55235000, MG# 55235001, MG# 55235002, and MG# 55235003). My transmission had a .8 mm shim located here.
- Another shim should be located at the rear of the shift drum, between the inner selector body and the case (immediately to the rear of part 27). My transmission did not have one located here, but required one that was .72 mm thick. I used a piece of 220 grit sandpaper to remove .08 mm from a .8 mm thick shim.
- When checking for end-to-end play on the shift drum, I followed these procedures:
  - I removed everything from the case except for the shift drum, the shaft that runs through the shift drum, the inner selector body (MG# 55236400), and the appropriate shims.
  - I replaced the cover on the case and secured it with several bolts before checking for any play.
  - When checking for play, I was primarily concerned with end-to-end play. But, I also paid some attention to the ability of the shift drum to rotate freely and smoothly. The shift drum doesn't rotate all that much, but I certainly didn't want it to bind, either.
- Once you have shims of the appropriate thickness on both the front and rear of the shift drum, you will need to carefully flatten one edge of the rear shim. This is necessary to allow for the gears on the starter pin (MG# 12236800) to engage with the gear on the inner selector body (MG# 55236400).

Check the shift forks for excessive wear

I'm not aware of any exact specs for how much wear is acceptable. Replacing them is not cheap. They run about USD $100.00 a piece - which is a lot of money considering that you might be able to pick up an entire used 4 speed transmission off of eBay for less than USD $100.00 delivered. Keep track of the relative position of each fork as you remove them. You'll want to check for wear patterns against the associated gear. My forks only had slight wear, so I reused them.

Special tools you will need

Generic gear puller to remove the clutch hub from the clutch shaft (this isn't so special a tool, but I thought I should mention it anyway)
For 5 speed transmissions, a special ring nut is used to secure the clutch hub. A special socket is required to remove it.
Special socket/wrench to remove the lock ring from the layshaft (the 4 speed and 5 speed transmissions have different nuts, so a unique special tool is required for each.)
Some type of wrench (perhaps a large pipe wrench, perhaps a special tool) for holding either the layshaft or the clutch hub while tightening the lock ring on the layshaft.

Transmission - The loop 4 speed transmission: An exploration

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I extracted this information from Rob Prins on the Yahoo! Loopframe_Guzzi news group. In [mostly] Rob's own words:

Rear view of assembled transmission.

Inside of rear cover.

Inside of transmission.

Shift selector shaft.

Egg-shaped retaining ring removed.

Another view of the shift selector shaft.

Selector inner body - the cause of much transmission rebuild anxiety; small spring-loaded parts that could sail into a dark corner never to be found. In reality the springs aren't quite that strong, although they will move the parts across your workbench.

Preselector assembly and rear cover.

Preselector assembly.

Preselector housing.

This view shows the shift drum, the neutral contact, and the neutral "button" on the shift drum. With the shift drum in this rotational position the neutral button touches the neutral contact, grounding the neutral light circuit (neutral light is on).

Neutral contact and external lug for neutral light contact.

In this view the shift drum has rotated so that the button no longer touches the neutral contact; the neutral light is off.

In this view the shift drum has been removed. The shift fork lugs and the plunger that interacts with the shift drum detents are visible.

Three rotations of the shift drum showing the two slots that engage the shift fork lugs and the detents.

"Gravestone rub" of shift drum showing the profiles of the 2 slots and the locations of the detents.

This view shows the shift drum detents for 1^st and N. The plunger is shown engaged in the 2^nd gear detent.

This is a mock up of the shift drum, the shift forks, and the layshaft. 3^rd gear is shown engaged. The picture shows how rotation of the shift drum moves the shift forks and consequently the "sliding dog clutches" or "sliding muffs" move along the layshaftand engage the different gears.

1^st gear engaged.

Neutral "engaged."

2^nd gear engaged.