Items to check on a new Le Mans

Posted July 11, 2002
Updated August 9, 2002

On a web-based message board I was reading at v11lemans.com, we got into a discussion about Moto Guzzi quality control, or more precisely, the apparent lack of it. Several items kept coming up as being problems. I decided to write up a list of them, so people could refer back and check for potential problems on their own bike.

I plan on taking pictures of these various parts to put in the list, although that may be a few days out.

If you know of more things that should be on the list, torque values, or have corrections, please email me.

Problem	Solution
Speedometer non-functional	Check that the transmission-end of the speedo cable is firmly seated (right side of the bike, near the border between transmission and engine crankcase). It's a friction fit, and will naturally tend to pull itself out, so some kind of retaining device (string, zip tie, etc.) may be required to keep it in place.
Loose/missing engine mount bolt	The factory didn't adequately torque down the engine mounting bolts. Check that each bolt (of four(?)) is correctly torqued (what's the torque value for them's with torque wrenches?). If the problem recurs despite proper torque, apply blue Locktite (or any other lightweight thread locking compound) to the bolt, then reattach. Torque value must be lowered with the locking compound in place.
Loose/missing shifter pivot bolt	Once again, poor factory torque. Apply correct torque and thread locker as appropriate.
Vapor lock, bike impossible to start when warm	One of the fuel lines may be getting too warm, vaporizing the fuel inside. This leaves a vapor pocket that prevents the fuel pump from working effectively. The fuel line may need to either be shielded from the heat, or moved to a cooler location. In particular, move fuel lines away from cylinder heads. In the short term, all you can really do is let the bike cool down for half an hour or so and try starting it again.
Valve cover weeping or leaking oil	Ensure that the cover retaining bolts are tightened properly (XX ft/lb, XX N/m). If the problem persists, the gasket may need to be replaced -- order early: parts availablility, at least in the US, seems to be very limited. If the bolts keep coming loose, apply some blue thread locker to them.
Timing cover (front of engine) weeping or leaking oil	Check bolt tightness (XX ft/lb, XX N/m). If the problem remains, gasket may need to be replaced. Apply thread locker to the bolts if they loosen themselves.
Shifter doesn't return to normal position after shifting	The shift lever return spring has probably broken. Obtain a replacement from Moto Guzzi, or have one made at a local spring winder (insert spring measurements here). You may want to order two, and carry one as a spare.
Transmission stops shifting at all	The shifter pawl spring has probably broken. This is the spring which ensures that the pawl is engaged in the shift selector drum. Order a replacement from Moto Guzzi or have a spare made. This is another spring that seems to break a lot, so carry a spare.
"Tank suck" -- bike stops running, and opening the gas cap produces an inrush of air	This is caused when the gas tank venting is not working properly. The tip-over valve can cause the problem if it's not in the right position. To remedy this, the valve needs to be moved to the correct orientation (which is?), so that it can freely allow air in. If the tip-over valve is properly oriented and the problem remains, the valve can be removed (with the danger that the bike will spill fuel if it ends up on its side), or replaced with a new part.
Fairing cracked at attachment points	The fairing attachment bolts were fastened too tight at the factory (if it's not one, it's the other!). Ideally, spacers would be installed to prevent the plasting from being bent when the bolts are tightened. Warranty replacement of the fairing parts is recommended if the damage is visible or appears to move.
Side panel bolts come loose	Repeat Locktite/torque procedure on these bolts as necessary.
Oil cooler braket broken	The stock aluminum oil cooler bracket has had problems breaking. A steel replacement (URL anyone?) is available, which is significantly stronger.
Engine pinging	This is a problem caused by too lean a mixture (usually). The problem is caused by a number of things, but is primarily limited to the fuel injection "map" on the Le Mans. Possible solutions include trying a higher grade (more octane) gasoline, ensuring that your air filter is clean, and installing a Power Commander (reprogrammable fuel injection computer).
Engine runs poorly	The fuel injection air intake hoses can come off, and are a poor fit to the injector bodies. The solution to this is to replace them if cracked, and mount them yourself as carefully as possible to avoid stressing them once they're mounted.
Gearbox leaks oil	There has been one report of the rear seal of the gearbox leaking oil. No remedy has been suggested yet, but at a guess tightening the cover bolts to recommened torque values will help.

Created by Ian Johnston. Questions? Please mail me.