Triumphrat

stu · 10-02-2006

I'm getting a rough feeling vibration, felt mainly thru the tank knee pads at a very narrow speed range- 48-52mph in 5th, 35mph in 3rd so its not related to wheel balance, wheel bearings etc but must be motor. I checked all the motor and exhaust mounts and they were all tight. This is new , and I have no idea what it could be. Any ideas please?

SCCTrim · 10-02-2006

If your bike has a aftermarket front sprocket....it could be the cause.

Aftermarket's are not rubber bushed.

DickBender · 10-02-2006

stu,
Have you balanced the carbs? Mine had a funny sort of vibration I got the carbs balanced and it has gone. It pulls a lot cleaner from low revs too.

Darcy

KingBear · 10-02-2006

It's your cell phone set on vibrate, silly. Your wife is calling to tell you to stop riding your stupid motorcycle and get your butt home so you can take out the trash.

badrufus · 10-02-2006

DickBender mentioned the first thing I think of when someone mentions vibration. The carbs on the Bonnies need to be kept synchronized. You'd be amazed at the difference in vibration (or lack of it) that a small turn on the synch screw can make.

stu · 10-02-2006

Carbs are definitely balanced, I use a vac gauge set up, but in any case, why the vibration only over a couple of hundred RPM?

toocaffeinated · 10-02-2006

Stu,
If you have done anything with your chain/sprocket, check to see if you have overtightened the chain. And make sure the tighteners are even on both sides? maybe? :???:

Mecchanica · 10-03-2006

Start with the basics, I guess.........engine mounting bolts, then other frame bits. Then on to the esoterica.....Cam chain tension, throttle position sensors, etc. Good luck.
Wups, you checked the bolts, so we're already into esoterica......*****. Guess I would go with what the other guys said. I'm a relative newbie.

[ This message was edited by: Mecchanica on 2006-10-03 00:25 ]

eagle · 10-03-2006

Or maybe the tank mounting bolts are loose?

Mecchanica · 10-03-2006

Redux..........as I think about it, there appear to be a lot of problems, relatively speaking, that seem to have to do with a resonance. It sounds to me that there is some gizmo that doesn't like the rattling that the engine puts out, (although it seems dead smooth to ME, with 38 years of flogging non balance shaft equipped ancient British machinery), and I have to think that it's an electrical part with a mechanical function.....like a switch.....and lord knows there are several suspects here.....kickstand switch, clutch switch, ignition switch, kill switch......wiring harness chafed or pinched........the list of potential culprits is long and it will be a hassle to get to the root these, and that's assuming that these problems stem from a common source. But if we can solve one, and then see it again in another bike, maybe we can put out a sort of technical service bulletin on our own.