Triumph / Royal Enfield 'Trifield' 500 trials - third gear jumping issues and causes discussed.

As well as the roughness experienced and probably caused by excessive layshaft end float, there was the little matter of third gear trying to jump out of mesh a couple of times during a recent test ride. Here, I discuss four possible candidates which, when they join forces, could very likely cause the problem.
Time to talk to the owner and order some new parts, I think!

[@norsehall309]

G'day Paul, l always find the way you explain the process of finding problems as a great learning experience for me and it expands by knowledge too no end, thanks mate, Neil 🤠.

[@paulhenshaw4514]

Thanks, Neil!

[@usefulblokestuff]

Really good video....good detective work. I do note that the advert following the video was for Dominos Pizza.....coincidence....or conspiracy!!!!

[@paulhenshaw4514]

Wow!

[@GrahamRozee]

Hello Paul, just found you on here. We've met a few times over the years, I'm a friend of Andy Sumner (Blondie) I own and ride 1960 T110 lived in Ffarmers until 2020 when I had yo move back to yhe East Midlands. Anyway good to see you're still working on the bikes and you're looking healthy.

[@paulhenshaw4514]

Thanks, Graham!

[@dasp125]

Always learn a lot from your videos!

[@stewartellinson8846]

It's like that famous supermarket advert - " every little bit doesn't help"

[@hermangibbs8163]

Thanks Paul.

[@Shaneshaneinoz]

I had an idea that the mainshaft second and layshaft third pinions may have been the same, so I checked the parts book (877-64). They aren't the same, but it says the mainshaft sliding gear is second rather than third. The good news is that you probably don't need to replace the selector camplate or mainshaft sliding gear. It's also possible that your layshaft shimming will fix the third gear engagement problem as well as the noise. I've learned a lot from your videos, and really enjoy your rides on those lovely local roads. With a little luck, I may hav contributed something back.

[@750triton]

Cumulative error. They improved the selector plate later on, with a strap spot welded across that point that's worn. It's otherwise identical

[@shug831]

Could the bush on the selection forks be replaced to give better engagement in the selection plate?

[@diversionbob8482]

Could the selector fork have an under size bush on it? Perhaps the slots are different widths and each fork uses a different OD bush?

[@Triumph-Tiger-90-Com]

I would be very reluctant to fit additional shims. Most wear in the C range boxes is the selector plate, high gear bush and first gear. I have a free pdf restoration guide on my website.

[@gordonsuddery4635]

Good work on the gear box problem thanks for sharing love the video, my best wishes to you from the Philippines ❤️💪👍😉😀😁🏁🏍️🛺🐑🇵🇭🏴󠁧󠁢󠁷󠁬󠁳󠁿

[@paulhenshaw4514]

Thanks 👍

[@richardtaylor7199]

👍

[@user-yi3gb4bu9o]

My respect, you always find a way. Time for a beer.

[@k1ckyscotland988]

Great piece of deduction Paul. You've certainly earned your Friday night bottles of beer to wash your pizza down.

[@stephencroft6481]

A pizza cake paul

[@stevec-b6214]

cannot fault your logic, Paul. Are these parts readily available?

[@paulhenshaw4514]

Thanks - and yes, I think so.

[@lesjones7617]

Wow!

[@jackbeanstock7710]

Hey Paul. i wonder. would these same symptoms in the gearbox apply to an BSA A65 gearbox as well? , ive got an 1965 "E" that likes to jump out of 3rd gear when riding the throttle any more than a gentle take off.

[@paulhenshaw4514]

Very likely, I would think!

[@ianh.6825]

How easy is it to obtain replacement parts such as this? Bearings are usually generic but what about the other bits - new old stock, good used or remanufactured?

[@paulhenshaw4514]

There is still good parts availibility for these machines.

[@PatrickWhitaker-ls2cs]

It's rarely just one thing.