(SOLVED) illusive shifting issues

[2-wheel-wannabe]

Hi all,

So I have been fighting with down shifting issues on and off for about a year. Ironically I had no issues until after having the dealer replace the shift mechanism as part of the recall.

About 6 months later I noticed that I started having issues downshifting from 4th or 5th. I would click the pedal down but I would remain in the same gear as before. It eventually got to the point that it was nearly un-rideable. I poked around the internet and found that no one had a solid answer. I even asked the local service manager and he didn't have an explanation.

So I took the bike apart myself because I really like to know how everything works and wanted to make sure that the dealer really had done the service. After taking the clutch out and poking around I saw how the mechanism worked and that it appeared to be slipping. I removed the mechanism and took it to the dealer. The service manager gave me a takeout part from a new bike. I dropped that part in and the bike shifted great again... until this spring.

Now passing 20K miles I am familiar with how the bike shifts, how much pressure is needed and when to add some clutch.

I decided I had enough after doing an entire track day in 4th. I could still shift down if I eased it into lower gears slowly. So apart it came. I ordered the race-kit star wheel for good measure. When I pulled the shift mechanism that I had put in there I noticed that the 'fingers' had substantial wear on them It had only been in the bike for about 6 months.

worn fingers:


Good fingers:


I put the race wheel (smaller neutral notch and re profiled first-second lobes) and the warranty replacement part back in. Now it doesn't want to shift at all... total junk. I'm getting afraid that I messed up the shift forks and internals at this point.

I pull the cover and clutch once again and start really diagnosing the problem. This is when I start taking the videos to analyze frame by frame what is going on. I replicate the action outside of the bike and really spend some time working out what tolerances and manufacturing/wear defects could be causing this issue.

Here is a short video of the mechanism in action:

http://youtu.be/8Y5VBHlWVMw?hd=1

So finally I take the warranty part that has the properly hardened 'fingers' and attack it with a Dremel tool. I strategically removed material to allow the 'fingers' to engage the star wheel more positively. I didn't want to remove too much so I re-assembled and tested it three times before I get the tolerances just right.

The distance between these two lines needs to be reduced:


So I removed material from the areas that are circled:


Until I could no longer see daylight: (and then a little bit more as it turned out)


For those of you counting I removed the side cover and clutch around 5 times in two days.

Now it shifts flawlessly and positively. With all the other work done to it in the last few months I couldn't be happier!

[Tremor]

Great work! Thanks for the dedication. I will probably have to do this someday.


Sent from my iPhone using MO Free

[TheLoneDeranger]

Haven't had this problem yet, but if I do, I'll know who to go to for help.

[Wayne's Striple]

What puzzles me is that it should shift flawlessly without needing to modify parts. IMO I would have returned it to the dealer and told them to install all the proper parts so that it shifts reliably and properly. I have read that prior to 2011 the shift detente spring can have quality issues and this was rectified for the 2012 model. - Wayne

[2-wheel-wannabe]

It's all about the tolerance in the manufacturing of these parts. If the dies become worn, it tolerances slip, these issues can pop up. I only removed a few thousandths of material. Dirt and oil mixed with a little bit of wear could cause this. Sure dropping in part after part ever few months until I get one that is biased in the right direction would work. However with 20K on the clock they are just going to chalk it up to abuse. I don't blame Triumph. This is a fairly simple part that was made to a budget. The engine/transmission is super precise. However this stamped and riveted mechanism is not. Also measuring the tolerances that are effected is quite difficult.

If you remove too much material you could quite possibly jam the mechanism too. Undoubtedly the pre-production parts and initial supply were all held to a higher tolerance or hand made.

Mass-produced items will always be a compromise. Engineering deadlines will always have to be met. Costs will always be reduced wherever possible. I consider one slightly out of tolerance part out of many thousands to be quite good!

That and this took me about 24 hours to fix versus weeks or more in the shop. And now I know more about my bike and how it works.

[2-wheel-wannabe]

And who knows, maybe I have bent something that caused this issue to crop up. All I know is that I am not the only person in the world to have this issue and want to put some solid research about the problem out there. More than just "that's how they shift" or "let the clutch out a bit" that I have seen recently.

[zyhano]

nice video showing how it works in action. I know the theory from my haynes motorcycle tech book but this makes it clear.
thanks!