Transmission questions

[Ercouper]

The '07 Rocket III that I bought a couple of months ago had a problem of what felt like jumping out of 2nd gear, or not going fully into 2nd if accelerating hard.
I finally got around to taking the engine out and apart to see what I was hoping to be an obvious problem. After disassembly it isn't too obvious.
The things I've found are...... All gears look great, with no broken or worn teeth. There does seem to be some wobble of the gears on the output shaft if flexed back and forth and I can get a .027" feeler gauge between the gears.....not sure if that is acceptable or not. Also the C4 shift fork has some wear on the side closest to the back of the motor. The only other odd thing is that 5th gear on the input shaft is somewhat tight and it takes a mild amount of torque to turn the shaft if you hold the gear. Is this normal? The detent spring is not broke but was wondering if there might be a stouter spring available (?). Any help or advice would be appreciated.

 

[R-III-R Turbo]

Probably need to back cut the 2nd gear to stop it slipping and jumping.

I can't picture which gear you're talking about but one of them has belleville washers beside it to stop it spinning freely, wonder is this the one you mean about having strong resistance to turning?

 

[Ercouper]

Probably need to back cut the 2nd gear to stop it slipping and jumping.

I can't picture which gear you're talking about but one of them has belleville washers beside it to stop it spinning freely, wonder is this the one you mean about having strong resistance to turning?

Yes, I was thinking that it must have been intentional (designed that way), 5th gear on the input shaft, that would be it. Thanks for the confirmation! One less thing to worry about.

 

[R-III-R Turbo]

Yeah 5th input that's it. Closest gear to clutch after the little 1st gear that's part of the intput shaft itself.
The Belleville washers act like a spring to hold resistance against it so the gear can be engaged.
This vid might help show

 

[Ercouper]

I ordered a new detent spring & a C4 shift fork today. I also called two Triumph dealers trying to find a mechanic that was familiar enough with these motors to tell me if the play that I'm seeing between the output shaft gears is normal or something that I should worry about, but was unsuccessful.
I'm not familiar with what is meant by back cut gears. Is this something Triumph did in later models?
I might also mention that my motor only has 16K miles and looks like new inside with no noticeable wear on any of the gears, only on the one shift fork.

 

[R-III-R Turbo]

Back cut is where the dogs and windows (male and female bits that mesh together to engage a gear) have a little machined off so that their mating faces are slanted, it helps a lot for the dogs and windows to catch and pull into each other.
Can you post a pic pointing to where this play is?

Also, if you can count the dogs and windows on your 1st and 2nd gear sets as there were some changes in the early engines.

 

[Sensfan]

I’m happy you posted this, I was just having the identical problem…..it sucks having to short shift 2nd…..

 

[R-III-R Turbo]

Get thee hence to Robinson Industries in New York, and don't forget the circlip mod and billet 4th

 

[Ercouper]

Back cut is where the dogs and windows (male and female bits that mesh together to engage a gear) have a little machined off so that their mating faces are slanted, it helps a lot for the dogs and windows to catch and pull into each other.
Can you post a pic pointing to where this play is?

Also, if you can count the dogs and windows on your 1st and 2nd gear sets as there were some changes in the early engines.

Thanks for the explanation of back cut. Now I understand.
My 1st & 2nd gears have the updated 4 windows version and not the 6 of early engines. My engine is # 330789 and I think ones before 300896 might have the 6 window gears (not positive).
I'll try and take a video showing the play that I'm talking about later today or tomorrow and post it.

 

[Ercouper]

I’m happy you posted this, I was just having the identical problem…..it sucks having to short shift 2nd…..

Is the problem with your 2013 R3? Did it start gradually over time, or start suddenly? How many miles on your Rocket?