Excessive play in drive train

[Ercouper]

I recently purchased a pair of Rocket III's, an '05 with 55K mi, and an '07 with 17K mi..
Let me say that this is my first experience with Rockets so I am not overly familiar with their quirks, common problems, etc..
After riding both for a while, I find that the '05 has more "play" in the drive train than the '07, which I would expect due to miles driven.
If cruising along at say 40mph at a constant speed and increase and then decrease throttle setting, there is a very noticeable clunk, clunk which is very annoying.
The '07 does the same but is not near as noticeable. My question is.......is there a common cause of this? Is the U-joint suspect? Play in the rear end pinion and mating gear? Bad shock absorbing rubber inserts in the rear hub? Or.....??? Pardon the lack of proper terminology. Any advice on where to look first? Thanks for any help or suggestions.

 

[TURBO200R4]

these bikes need to be greased on a regular basis on the final drive (differential) splines. they like to wear out i do mine at every tire change
6 to 8000 miles. they can be replaced with later final drive guessing 09 up that have a lager spline drive shaft and larger final drive spline.
also be careful of the final drive drain bolt it breaks very easy.
you can do a search this site has a lot of info.

 

[wzuccarello]

I recently purchased a pair of Rocket III's, an '05 with 55K mi, and an '07 with 17K mi..
Let me say that this is my first experience with Rockets so I am not overly familiar with their quirks, common problems, etc..
After riding both for a while, I find that the '05 has more "play" in the drive train than the '07, which I would expect due to miles driven.
If cruising along at say 40mph at a constant speed and increase and then decrease throttle setting, there is a very noticeable clunk, clunk which is very annoying.
The '07 does the same but is not near as noticeable. My question is.......is there a common cause of this? Is the U-joint suspect? Play in the rear end pinion and mating gear? Bad shock absorbing rubber inserts in the rear hub? Or.....??? Pardon the lack of proper terminology. Any advice on where to look first? Thanks for any help or suggestions.

I noticed the same thing. I have an 05 with 12 k miles and a 2018 with 7K miles.
I noticed the clunkiness and slack was much greater on my '05.
If you have hem in 1st with engine off and gently rolled the bikes to and fro to feel the slack, the 05 rolls about 2.5 inches slack and the 18 has about 1.5 inches rolling slack.
Further research I found that a remedy for the early rocket transmission issue was to remove every other dog on one of the main drive gears. This would account for the extra slack.
Here's a screenshot about the gear change related to engine numbers.
The poster was also inquiring about drive train slack.

 

[Ercouper]

I noticed the same thing. I have an 05 with 12 k miles and a 2018 with 7K miles.
I noticed the clunkiness and slack was much greater on my '05.
If you have hem in 1st with engine off and gently rolled the bikes to and fro to feel the slack, the 05 rolls about 2.5 inches slack and the 18 has about 1.5 inches rolling slack.
Further research I found that a remedy for the early rocket transmission issue was to remove every other dog on one of the main drive gears. This would account for the extra slack.
Here's a screenshot about the gear change related to engine numbers.
The poster was also inquiring about drive train slack.

Thanks for measuring the slack. I will have to use your method to compare my '05 to yours. I'll try and do that soon and post the results.
Of course the measured play would also include any play in the bevel box, which could be part of the problem with mine. I noticed that the bevel box drain plug was weeping and when I removed it to change the lube, only 3 or 4 oz's came out......not good. I refilled and reinstalled the drain plug with new washer. Not leaking now but not sure how much wear might have been prevented if the fluid level had been checked on a regular basis.
I know my '07 has the 4-window dog's, and I assume my '05 must have the 6-window version. I wasn't sure why Triumph made the change. Was it to reduce slop, or to make gear changing smoother, or ???