dowieze Posted September 9, 2022 Author Posted September 9, 2022 Thanks for the advice. I have a check up. 1
dowieze Posted October 5, 2022 Author Posted October 5, 2022 Le mans has been repaired. Thanks everybody for the feedback and advice. Special thanks to docc for the technical support and for Scudd for sending me a new selector spring. I'm back on the road again and the gearbox works fine, for a guzzi. I hope for a long time now. Best regards. Marc, Belgium, Ypres 4 1
dowieze Posted March 1 Author Posted March 1 Bad news. The selector spring on my bike broke again after 3000 km. For the third time in three years. In the garage they replaced 5 springs in 20 years, includes 2 times on my bike. They do not find the cause. Currently they trying to modificate the gear box by reducing the travel way of the selector spring. I hope it will work this time. Any suggestions are we welkom. Best regards Marc 1 2
LaGrasta Posted March 1 Posted March 1 Sorry to hear this has happened yet again, must be so frustrating. This hasn't happened to me, but @Scud is only 20 miles from my home. Hope he has some in stock.
Scud Posted March 1 Posted March 1 I still have a lot of springs. @dowieze I'll send you a PM. You should ask your shop to stop their mods and wait for this spring. We have ZERO failures of this spring. 5 1
po18guy Posted March 1 Posted March 1 4 hours ago, dowieze said: Bad news. The selector spring on my bike broke again after 3000 km. For the third time in three years. In the garage they replaced 5 springs in 20 years, includes 2 times on my bike. They do not find the cause. Currently they trying to modificate the gear box by reducing the travel way of the selector spring. I hope it will work this time. Any suggestions are we welkom. Best regards Marc From the "unwinding" of the spring at the time of failure, it appears that selector travel is a prime culprit.
Scud Posted March 1 Posted March 1 Oh wait... reading back on this thread, and looking at your photo, that does appear to be first failure of new spring I have ever seen. And it looks like the poor thing was completely mangled - in a way I have not ever seen before. What is happening inside that transmission? Inquiring minds want to know. 2
Lucky Phil Posted March 1 Posted March 1 19 minutes ago, Scud said: Oh wait... reading back on this thread, and looking at your photo, that does appear to be first failure of new spring I have ever seen. And it looks like the poor thing was completely mangled - in a way I have not ever seen before. What is happening inside that transmission? Inquiring minds want to know. Hmm, I smell something fishy here. That image isn't from a simple fatigue failure thats something bazar and or possibly self inflicted. Does this bike have the old original and faulty oversize shift arm boss? Phil 3
Scud Posted March 1 Posted March 1 Also - one batch of springs I had a section that was too long. It was the short arm at the 90-degree bend. I trimmed them all by hand, but it's possible that I left a few too long. When you re-assemble, be sure that short arm is not catching on anything. Happy to send a free replacement spring - and a few free extras for your shop. (but sorry, not free international shipping). 2
Lucky Phil Posted March 2 Posted March 2 Plot thickens. I scaled the image as best I could and it does appear that the right angle tab on the end of the spring is significantly longer than the stock spring. Maybe this one missed the trim process and was catching on the cover? Phil
Lucky Phil Posted March 2 Posted March 2 3 hours ago, Scud said: Also - one batch of springs I had a section that was too long. It was the short arm at the 90-degree bend. I trimmed them all by hand, but it's possible that I left a few too long. When you re-assemble, be sure that short arm is not catching on anything. Happy to send a free replacement spring - and a few free extras for your shop. (but sorry, not free international shipping). I'm looking at my spare springs Scud, how did you trim them? cutter or grinder? How overlong do they have to be to cause an issue with the cover? Phil
Scud Posted March 2 Posted March 2 Trimming - I set up a little template and used a cutting wheel on a dremel tool. Length/interference - I don't think the issue was with the cover. I think the interference was with another moving part. The "right angle tab" only needs to be as long as the thickness of the part that it rests on. I might have posted a photo in the re-engineering the shift spring topic... but that could take hours to find...
Chuck Posted March 2 Posted March 2 Just eyeballing, the length of the bent tab, it looks ok.. but.. on a "factory" spring, I can see a very small stress riser from the spring winder tooling at about the area this one broke. (!) I don't know if I can get a picture or not, I'll give it a go. When I wound the springs on the lathe, that wouldn't be there. Edit: Ok, here ya go. I'm betting the tool needed to be polished. 2
Scud Posted March 2 Posted March 2 Here is the link to Chuck's drawing showing the specs, including the length of the right-angle tab. 1
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