Transmission Shift Spring Failure FAQ

al_roethlisberger · November 19, 2003

Moto Guzzi V11 Sport/LeMans Transmission Shift Pawl Failure FAQ

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Introduction:

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Many owners of V11 Sports and LeMans have experienced a failure of the shift mechanism where the transimission will no longer shift out of the current gear, often 2nd or 3rd. Upon inspection, the cause is found to be the "shift pawl return spring" breaking where it makes a tight 90-degree bend.

For many owners, this has been happening around a 5k mile interval regularly, and often happens again with factory replacement parts.

At this time Moto Guzzi has not addressed this problem, although there have been rumors of an official updated part that have yet to be verified.

However, after investigation by several other owners, looking into spring design and linkages within the transmission, it now appears that the culprit is not the spring itself.

It appears that a manufacturing lot of shift linkages with 16.5mm diameter spring bosses, instead of the prescribed 15mm, were delivered to Moto Guzzi, and installed on primarily 2002 V11 Sports/LeMans, but may show up on a few earlier and later bikes.

This outsized boss causes the shift return spring to bind and not cleanly rotate around it's shaft, reaching coil bind, and putting undue stress on the tab at the end of the spring itself. Over time, this stress causes the spring to break.

The solution is to either replace the shift arm link with one using the correct 15mm diameter boss, or grind down the boss on a defective unit to the correct size.

Sources for alternative springs as listed below are still relevant, as supplies from Moto Guzzi can be time consuming to source, however the root cause seems to not be defective spring materials or manufacture, but the boss on this shift linkage.

As of April, 2005, Moto Guzzi issued the following Technical Bulletin, which confirms that the oversized boss is the problem:

Model: V11
Problem: broken gear change pawl spring

Solution: In case of breakage of the pawl spring A in vehicles with frame numbers before KT111435 - KS112350,

the pawl B should be changed (when asking for the spare part, you automatically receive the pawl updated

version).

The change consists in the reduction of the diameter on which the spring rests from 16 mm to 15 mm.

Part nos: 04 23 51 01 for the new arm, 04 23 83 00 for the OEM spring.

However, be aware:

OK, new update(July 19th, 2005)

Called all around the US parts guys; MPH, Harper's, Motointernational.

Apparently, the part number IS NOT sufficient to insure you get the arm with the 15mm boss. There are still old arms floating around with the wrong 16mm boss under both part numbers: 04235101 AND 04235201.

I spoke to someone very knowledgable of the problem in Seattle at MotoI. He is now trying to find out how to deliver me a part that is sure to be the correct 15mm size. He measured the boss size of a part he had on the shelf, number 04 23 51 01, and found it to be the incorrect 16mm size. As you know, I ordered a replacement arm 04 23 52 01 from Harper's MotoGuzzi and received another fresh arm ALSO with the incorrect 16mm boss size.

Listed below are URLs and contact information for general information and several online discussions.

Information:

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A purportedly improved aftermarket spring is available from:

Bonnie at (405)524 7223

- Request a "Moto Guzzi shifter spring." Cost is $12.50USD

Hank Blackstock's Replacement Springs(Same as above)

Project to special order a complete set of custom made springs

V11 Forum Topics:

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Spring Failure and Boss Diameter Detailed - With Photos

Spring Boss Diameter Issue - Final Solution