Shudder Upon Decceleration

[redliner1973]

I was riding today with my local group and when we got onto the interstate everyone shot up to 85mph. I was in the midddle of the group running right with them no problem, but when we had to slow for traffic ahead, when I let off the throttle, I felt a shuddering somewhere in the lower rear under my seat, felt like something went out of balance or something, really strange, I have never felt this before, of course I usually don't go faster than 70 anyhow. It went away when i throttled up again, and I could only reproduce it ( to a somewhat lesser degree) when I got back up to 90. My balance weights are still on both wheels, and no loss of control was evident, just that strange shuddering vibe, and at lower speeds I could not feel it. And Only on Decceleration. Bike seems to have run normally the rest of the way home, and now has me worried. Any suggestions? :twisted:

[Anonymous]

Shudder

Hello, two years ago I had the same sensation you are experiencing. I checked quite a few things before I found out one bolt on my front u-joint had completely backed out and the remaining three were loose as well. By the way, I discovered this by noticing a small tear in the rubber boot that shouldn't have been there. Cure was replacement of all four bolts and loctite as well ( there was no discernible evidence of any loctite on the bolts) Hope this helps you.

[argonsagas]

It is rotational, so check everything that rotates.

The shaft is definitely a possibility, and bearings are also possible, but the most likely thing is wheel balance.

Do you have a tire sealant installed? If so, have you been leaving the bike parked for extended periods of time? That could affect wheel balance as it can settle, especially if it has been in there for a couple of years.

[redliner1973]

I will pull the boot and check, I hadn't though of that, but have looked towards maybe the u-joint itself. I know it is not the tyre, I was balance when new ( about 2 months ago) the weight is there, and its only on coast-down, not a tyre-type vibe, you'd have to ride it to see what I mean.