Bonneville America Forums Forums Technical Forums General Tech Cush Drive?

Couple of questions... what is it? how do you know if it needs to be replaced? What are the consequences if you don't?

A little caution on cush drive replacement - based on my experience - your results may vary...

I have an 03 America with spoked wheels. I bought the Thunderbird cush drive a few years ago based on recommendations on here and it just didn't work for me. The driveline was so tight, you could feel every vibration the engine made right through the seat and the handlebars. I gave the Tbird cush to Snert, and as far as I know, he is happy with it.
Shortly after that, I bought a chromed Speedmaster rear wheel off of ebay. I also bought a drive hub and had that chromed. I bought a new cush drive from my dealer and put it all together and everything seemed ok. A bit of play, noticeable when you let off the throttle suddenly, but I could live with it.
Recently, I bought a new rear tire to install on the SM wheel, and also got new sprockets and chain. I figured what the heck, let's replace the cush again. So I had the dealer order me a new SPEEDMASTER cush drive. I removed the rear wheel to get the tire installed and started to install my spoked wheel so I could continue to ride in the meantime. The new SPEEDMASTER cush drive did not fit in the spoked wheel. It is a lot beefier, but that wasn't the problem. The problem is that the spoked wheel has a series of "nubbins" where the spoke nipples seat in the rim right where the cush drive goes. The SM wheel, being a cast rim, does not have these protrusions. Checking the original cush from my spoked wheel, sure enough, the rubber lugs have little cut-outs in them to allow for this. The SM cush does not. The lugs are solid.

Now,if this cush drive epiphany is only mine, and everyone else knew this already, I apologize in advance.
But my advice would be to contact your dealer and get the correct cush drive for your bike and check it over before you install it....

The p/n for an 03 America spoked wheel is T2012230.
Bikebandit lists the p/n for an 03 America AND 03 SM as 5567931-001. (?)
The SM cush I just got from my dealer is a p/n T2012201.

Whether they updated anything I just don't know. But to be on the safe side, I'd order whatever p/n is called for for your year and model. That is, if you even need to replace it.
Now back to our regularly scheduled programming....

My two cents. I also installed the t bird cush drive, per the advice given here. Works fine for me. Didn't notice any vibrations or other. (But as I've often said on here, after riding the "old" Triumphs for thirty years, I don't notice even small children and dogs under my wheels, everything is smooth to me in comparison with the newer BA.)

I used to have a Yamaha that had a cush drive in it and never knew it until I took it apart. Never had any slop or that jerky feeling when rolling on or off the throttle. Sold it with the original drive parts in it years later. This bike, my TBA., has had excessive play since day 1! I thought the chain was loose at first and got off and checked it. After a while I got used to it, even though it makes slow speed handling a bit of a choir. Recently I took the riders safety course and the whole day is spent riding under twenty five miles an hour; on the gas, off the gas, slaloming around the cones,etc. Every time I changed the throttle setting, I'd feel this un-nerving bump when the slack was taken up, and it made it difficult to do some of the maneuvers that are required. In my opinion, this is a poorly engineered part to be so sloppy, and it shouldn't wear out for at least 60 to 100 thousand miles. These parts don't rub against each other, they’re a "bump stop" to take the shock out off the drive train. When there's space between the paddles of the hub and the rubber slots, this thing is causing shock to the drive train and to me. Just thought I'd blow off some steem about the only thing I think is substandard on my bike.

At last someone that has the same problem as me I brought a new 07 S/M and from day one it had too much slop in the cush drive. I went to JCS triumph dealer in Perth Western Australia and was told to take the back wheel off and squash a old inner tube in there to take up the slack not bad considering it was still under warranty(I think the back wheel is not the only thing that is slack).So will the T/Bird cush rubbers fit the 07 mag wheel and tighten things up? I also had the cush drive replaced under warranty but it made no difference.It must be the mag casting.

I don't believe the manual states a spec on the cush drive free-play. But, with the rear wheel lifted and the bike in gear, if you can rock your wheel back and for more than 1" or so it might be time to replace the cush drive.
I just took a piece of vinyl baseboard, cut shims to take the the slop and slipped them in front of the rubber shim.
This 95% of the slop out of the drivetrain and I have had no vibration issues. It cost me about $4 at Lowes.

It is a little fussy getting the shims in place.

I have pix somewhere.

I cut some shims out of 3mm thick rubber sheet. It took all the play out of the cush drive. That was 10000 Klms. ago and it's still got no play in it.

Good stuff Frank I'll do that, I'm sick off that lash that makes riding in traffic sh!t.

Hey Skull. It takes all the play out of it and if you use a little washing up liquid it fits together real easy. Why buy a new part if you don't have to.

beside reducing the back lash, I also found that selecting neutral worked every time with only one click. Before that, sometimes it took a few goes

Someone from here cut up an old leather belt for shims some time ago. Worked ok for them.

Here's my shim solution:

I may have finally discovered my throttle lag problem. Every time I'd roll off the throttle and back on, I would experience serious throttle lag. I fiddled with my throttle cables, raised my needles, ran non-ethanol gas then just learned to live with it. I was experiencing the same thing Chip described above.

Tonight I removed the rear wheel to have the tire changed and found this:



Evidently my cush drive was the culprit, guess I'll be buying a new rubber damper $79.00+ and shimming it.

+1 on the El Cheapo fix. I cut up an old bicycle innertube
for shims. It's worked for 10k miles so far.

So I called my dealer and it is under warranty, but replacement has to be original America part, cannot sub the T-bird part. Meh, better than the $79 replacement cost, I'll just have to shim it.
He said the cush drive is not a common problem on our bikes, (that he's heard of). So I guess it must just be the handful of owners on this forum. I'll take the unit down to him this Saturday to inspect and hopefully he'll have the replacement.

I'll update on the throttle response when I get it back together.

After re-reading that thread again, I think you hit the nail on the head regarding the throttle issue. The jerk you felt could have very well been the slack in the cush drive coupled with a loose chain. Before I adjusted my chain this summer, I notice a similar sensation when accelerating. Had nothing to do with the engine. I learned to finesse the throttle to reduce the jerk. After I adjusted my chain, the problem went away.

I got the tire on last night, replaced the rubber damper, adjusted the slack in the chain and rode my bike into work this morning. Unfortunately I am still experiencing the same throttle lag and jerky sensation when accelerating and decelerating.

I give up and the bike is going to the shop next week. If they can't fix it then I'll have to consider trading it on the FI model.

How much play do you have in the throttle?

I checked on my bike at lunch and the chain seemed a little slack...then I realized what I did.

I am so used to lubing the chain with the bike on the lift I never thought to lower the bike to the ground before adjusting the chain.

Stupid stupid stupid

Did you shim the new cush drive? Because when I got mine replaced under warranty it was still sloppy, also I have heard of someone having the cush replaced under warranty with a T/Bird one.

Yes, many of us have put in the Thunderbird Sport (not the new finless Thunderbird) cush drive. Much tighter and betterer.

The dealer wouldn't replace it with the TBird one under warranty, it had to be an OEM part for the America. I didn't shim it because I want to see what it does between now and March when the warranty expires. The mechanic at the dealer suspected the axle was over torqued at the factory but I didn't find it overly tight when I removed it.
I adjusted the chain again last night and we'll see how she rides into work this morning.

EDIT: She is alot smoother on the highway at low RPMS, a definite improvement but I'm still experiencing lag through intersections in town. I'll take her in for the 12K tuneup next week and have the mechanic fix it.

My dealer replaced mine with the TBird one on warranty. I was told that it was the recommended replacement for ones that got mushy early. You would think it would become the stock part since it works better.

Quote:

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The mechanic at the dealer suspected the axle was over torqued at the factory

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Sounds like they were bullsh@tting.

To people who are new to mechanical stuff, lots of tradesmen just make it up as they go. They must find it amusing I guess and also to give you an excuse that gets them out of doing anything about it.

I'm no mechanical guru, far from it but overtightening the axle has more danger to shearing the axle thread than anything else doesn't it?

In fact I always tighten my axle just a bit past the torque specs and haven't had any probs at all.

FYI, I replaced my cush with the tbs and have never had a problem since and boy was it a tight fit. fantastic

My dealer told me it was a weak muffler bearing...........Ya, that's how stupid some dealers think we are. Everyone knows it's bad batteries in the auto sky-hook...V.

has anyone ever changed the wheel itself to a wheel that dosent have a cush drive built into it i have wanted to change it to a 16" rim not a 15" if anyone has let me know how it worked out