Something Failed, let’s find it! Transmission Analysis.

[TURBO200R4]

Hey guy,

For test purpose only, why don't you try, while in 5th and it's making noise, to put a little pressure up on the shifter and same down just a little to see if your noise goes away ?

 

[Claviger]

EDITING: I confused myself typing this initially.

Regarding the shift fork wear. The faces that are worn are the 3rd gear side of the 2-3 fork and 1st gear side of the 1-4 fork.

I attribute the wear on the 3rd side of 2-3 to the quick shifter. It's the most common shift I do using it, almost always between 7400-8000 when I use the QS, and it is the longest throw dog ring, meaning the fork must move laterally the most.

The wear on the 1st gear side of the 1-4 fork, I attribute to a BAD HABBIT I have of rev matching going down from 2 to 1 at 30 mph or so and engine braking as approaching stop lights/signs.

If you're using a QS, understand that your likely wearing the upshift side of the 2-3 fork quickly. The bike had 8,900 miles when it went to NJ, it now has 11,700, 2,800 miles so the wear is fast!

Since my trans is back cut, it requires a lot more force to slide the gears away from each other, so, by using the QS, your starting the movement under full power, then it cuts fuel/spark as you get to the threshold of the QS internal switch to activate, but that brief time period where your pushing on the lever under full power, its going to grind the fork some prior to fuel/spark being cut and allowing it to release and upshift.

The good news on the forks? They're straight, so while it did cause a little bit of wear, it didn't bend them while doing so.

 

[Claviger]

Disassembled:


3rd Gear Circlip, Beveled edge was facing thrid gear, sharp edge towards 2nd, as it should be. Wear marks are on the 2nd gear side of the circlip, indicating axial force applied during 5-4 downshift:


4th Gear Circlip, Beveled edge was facing 4th gear, sharp edge towards 5th, as it should be. Wear marks are on the 4th gear side of the circlip, indicating an axial load applied during 3-4 upshift! This is a new data point, I'll be looking more into it. It means 3-4 upshifts can also cause loading across the two splined bushes that 3rd and 4th ride on, and into the 3rd gear circlip. The key though, is the 4th gear circlip stayed in place, so as it applied load, the 4th gear circlip would have limited the amount of force transfered to the 3rd gear circip when the splined bush slip away.



3rd gear splined bush, you can see on the face wear, how it's getting mashed against the circlip:


This is the 4th gear splined bush, by comparing you'll see less wear, indicating the second mode of axial loading through 4th into 3rd is not causing the same load that 3rd is applying to it's splined bush or circlip. This supports the primary failure cause being 4-5 downshifts.


I also need to add, the 3rd gear circlip has far far less tension than the 2nd or 4th gear clips. Clearly, it's been beat and stretched over and over and eventually slipped up, and over, the groove face it's supposed to ride in.

This all supports the idea of cutting and using larger, stronger, circlips to extend the service life of the clip and prevent gears mating in abnormal ways.

 

[Claviger]

The good news is, all damage is fairly limited. From what I can see I'll need the 3-4 input gear, 3 outoupt, 4 output, splined bushes for 3 and 4 output, circlips, and nothing else shows any damage just a little normal wear, including all the bearings. That assumes the shafts are straight and that I didn't bend the input shaft. I have no good way of measuring shaft runout, so I'll find out when robinson gets the parts.

 

[Tripps]

Roll it across a piece of glass, for lack of a granite plate, you'll know.

 

[Jvheli]

Disassembled:


3rd Gear Circlip, Beveled edge was facing thrid gear, sharp edge towards 2nd, as it should be. Wear marks are on the 2nd gear side of the circlip, indicating axial force applied during 5-4 downshift:


4th Gear Circlip, Beveled edge was facing 4th gear, sharp edge towards 5th, as it should be. Wear marks are on the 4th gear side of the circlip, indicating an axial load applied during 3-4 upshift! This is a new data point, I'll be looking more into it. It means 3-4 upshifts can also cause loading across the two splined bushes that 3rd and 4th ride on, and into the 3rd gear circlip. The key though, is the 4th gear circlip stayed in place, so as it applied load, the 4th gear circlip would have limited the amount of force transfered to the 3rd gear circip when the splined bush slip away.



3rd gear splined bush, you can see on the face wear, how it's getting mashed against the circlip:


This is the 4th gear splined bush, by comparing you'll see less wear, indicating the second mode of axial loading through 4th into 3rd is not causing the same load that 3rd is applying to it's splined bush or circlip. This supports the primary failure cause being 4-5 downshifts.


I also need to add, the 3rd gear circlip has far far less tension than the 2nd or 4th gear clips. Clearly, it's been beat and stretched over and over and eventually slipped up, and over, the groove face it's supposed to ride in.

This all supports the idea of cutting and using larger, stronger, circlips to extend the service life of the clip and prevent gears mating in abnormal ways.

The groove width and diameter on the shaft is critical.

 

[Claviger]

Thanks @Jvheli , this further supports having robinson do the circlips. I fully believe Robinson is capable of holding tighter tolerances than whoever makes the parts for Triumph.

Ultimately, I'd love to be able to use a spiralock so it has full circumference contact and resists the twisting action mentioned in that picture ultimately leading to failure. The 3rd gear clirclip is, indeed, visibly twisted.

 

[Jvheli]

Thanks @Jvheli , this further supports having robinson do the circlips. I fully believe Robinson is capable of holding tighter tolerances than whoever makes the parts for Triumph.

Ultimately, I'd love to be able to use a spiralock so it has full circumference contact and resists the twisting action mentioned in that picture ultimately leading to failure. The 3rd gear clirclip is, indeed, visibly twisted.

A proper fit should be a snug fit. If it just jumps right in the groove its no good. I have long suspected (as did you) that the trans issues on the r3 are really no more than quality escapes on a few shafts made by whomever Triumph sources them from.

 

[TURBO200R4]

A proper fit should be a snug fit. If it just jumps right in the groove its no good. I have long suspected (as did you) that the trans issues on the r3 are really no more than quality escapes on a few shafts made by whomever Triumph sources them from.

I disagree that the clip should fit snug i have been working on auto trans since 1966 and have never seen a circlip fit tight in the grove. it should go in w/o drag and clamp tight at the bottom of the grove.
example if it went in tight when it was hammered it would tend to open up and stay that way until it moved out of position.
when i check one i will put a little pressure to open the clip and make sure that it turns free in the grove.
of coarse a little bigger and stronger clip would be a plus that way they can straighten the grove.

 

[Claviger]

They all fit as you describe turbo, snapping in when aligned right and can be rotated around the groove with some force/resistance except 3rd gear. Clearly because it's all sorts of deformed/stretched.

It's snug, if it's not aligned right with the groove it wont slide in, kind of a "just right" fit without interference. Really, I think third's circlip popped out from just being beaten to death.

I wish I knew if the output shaft had been replaced in 2015 and then at Carpenter's in 2017. Alas, I don't know if this is the same as original shaft or not, meaning, I don't really know the service history of this shaft in particular.