Gregory Bender

Engine break in / initial start after rebuild

Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models


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Thanks to Steve (chucktbt) for providing the following information on the Yahoo! Loopframe_Guzzi news group. In Steve's own words:

This is the proceedure I've followed for the last 20 or so bike motors I've built up (about 15 Triumphs, a couple of Hondas, a Harley Davidson Panhead, and a Guzzi).

I put a large box fan in front of the motor, run the start off and on for about 30 seconds after the oil light goes out. Then, switch on fuel and coils (or magneto).

I fire it up and immediately put it at around 2000-2500 RPM for 7-10 minutes (or until the valve covers get warmer than I'd like). Use a clock; 7-10 minutes can feel like forever. I don't bother varying the RPM and I don't let it drop below 2000.

I then leave the fan on the motor and let it cool fully. Change the oil (I dropped the pan on the Ambo) check the valves, and go for a 10 mile ride. Nothing special on the 10 mile ride. I ride it like I normally would, just not all the way to redline. The only special thing I do is to find a hill or two and belt the hell out of it on the way up. I also tend to run the motors up to about 34 of redline then shut the throttle and let it engine break down to about 10-15 miles an hour. I do that about 5 or 6 times in a row to seat both sides of the rings.

Come home, check for leaks, let it cool. Retorque, valves set. Another 10-15 mile ride. Change oil, drop pan.

Ride it until it hits 50 miles, retorque heads; check fasteners for tightness. With nikasil cylinders you're more or less broken in by this time - valves/cam/followers are pretty much there too.

Ride it until it hits 100 miles, change oil/drop pan, retorque.

Ride the piss out of it. At 300 change oil and retorque.

Ride the piss out of it. Change oil/drop pan at 1000; check valves.

After 1000 I resume normal service schedule. You probably won't have to do this because you only did the top end (or at least thats what I gather from your post). Iron bores will shed a bit of material for the first 300-500 miles; nikasils should be done by 300 miles.

I really only adhere to rev limits in the first 100-200 miles. Depends on how the motor feels and how warm its running. The main thing is to not lug it or let it overheat. I think way too many people baby motors. That is a good idea at first; but if you've built it right, you can run it pretty hard out of the box.

I do more oil changes than most folks - mostly because the motors I've built don't have oil filters. I figure its cheap insurance to drain the oil often.

I've never used break in oil. Just regular oil - usually 15/40 diesel oil (Rotella) or 10/40 of just about any manufacture. I don't use synthetic oil - almost all ring manufactures tell you not to. This isn't an issue for the factory (newer bikes or cars that come with synthetics) because they belt the hell out of motors before delivery on break in oil and then refill with synthetic.

There will be TONS of different opinions on how to do the break in - so evaluate them all and decide for yourself. You really can't go too horribly wrong unless you let the bike idle forever and overheat :0

Thanks to Steve Odell for providing the following reply to Steve's (chucktbt) post. In Steve's own words:

I agree with all of this, especially the 2000-2500 RPM for 7-10 minutes. Flat tappet motors will ruin the cams and lifters on initial run in if you don't do it right. I've seen solid lifters get shaved to nothing and cams flattened out on bad run ins. I've always run in new 2 and 6/8 cylinder flat tappet motors, bike/car/truck, this way though as cars are water cooled I usually run for 20 minutes at 2,000 RPM. Regardless of the motor use, car or bike, if it's a flat tappet motor the most important time of its life is the first 10-20 minutes.

Also, whatever oil or additives you use make sure it has loads of ZDDP in it. Add extra, it doesn't hurt. There's lots of it in break in oil.

And as noted, no oil filter on this bike so change oil all the time. I never went past 800 miles without changing it.