Vibration thro' footrests

I have the above at any reasonable road speed. My tacho is not working properly but the rpm is around 3-4000rpm. I have set the iso's with feelers but this bike doesn't feel as smooth as my old Commando used to be. I haven't had all the iso's apart so things may be old in them but is it normal to get vibes thro the footrests or have I other issues on the way??

When going down the road it speed during the vibration condition, does the vibe go away when you pull in the clutch? If so try this......

1. Pull the tank and loosen the side plate bolts and the head plate bolt of the head steady.
2. While sitting on the bike with the stand up, not touching the ground, and while offering as much of your body weight as possible without tipping over, tight the side plate bolts then the head plate bolt.

Report back.

Good protocol pvisseriii I'll try it on Trixie Combat, which is pretty darn nice but not optimal yet. Most peg vibes implies too tight front iso, but could also be imbalance inside engine parts too. ugh.

Thanks Pviss. What do you mean by head plate bolt? The three screws/allens holding the plate to the head? Also please can you clarify point 2? Do you mean sit on the bike with no stands down and bounce it around to let it settle in the best/equilibrium position then tighten the side plates then the head plate? That would make sense and may be my issue as I tightened the head plate first then the sides and it may have twisted. Is that what your getting at?

FastFred said:

Thanks Pviss. What do you mean by head plate bolt? The three screws/allens holding the plate to the head? Also please can you clarify point 2? Do you mean sit on the bike with no stands down and bounce it around to let it settle in the best/equilibrium position then tighten the side plates then the head plate? That would make sense and may be my issue as I tightened the head plate first then the sides and it may have twisted. Is that what your getting at?

Click to expand...

You wrote "What do you mean by head plate bolt? The three screws/allens holding the plate to the head?" YES!

You wrote "Also please can you clarify point 2? Do you mean sit on the bike with no stands down and bounce it around to let it settle in the best/equilibrium position then tighten the side plates then the head plate?" Yes!

You do not have to jump around, just make sure your weight is on the bike like you are riding down the road. IE loaded. I would tighten the sideplates to the rubbers first then without moving around too much, snug the head mounting bolts, probably the 2 outside ones cause it's easier, then tighten specs all around.

Something good to know. Have to try that procedure some day. Thanks for the tip pvisseriii.

Thanks Pviss. Will try that tomorrow and report.

Cheers

travelerjerry said:

Something good to know. Have to try that procedure some day. Thanks for the tip pvisseriii.

Click to expand...

Cool, you will see that both the main headsteady and the side plates are slotted for proper fitting. You will be surpise to how much movement there is when sitting on the bike versus not sitting on the bike with the head mounting screws loose.

Before doing Pviss's protocol look at the rubber cushions to see if distorted under load just sitting there. Also bounce tug on engine to get a sense which way to alter.
I was recently surprised on Trixie to find rubbers strained but also the 750 type base plate bent too boot, so much its slots didn't allow shift enough to compensate. It went together like this w/o any strains so missed it at first. Once corrected Trixie got smoother and sooner. Acceptably nice now over some others I've ridden but think there's more to gain yet. Trixie is not exceptional compared to best I've tasted and heard reports of by non-owners riding them.

I've often wondered if there was a way to set the load on the top iso. Thanks pv, I'll try it, I get tingles in the feet at 3000. Doesn't really clear up until 4K. I'm still planning on the Hemmings adjusters this winter after I recover from the root canal and crown. UGH, that was like 2 years heating with oil.

Dave
69S

Well I tried all that and it didn't work but it's a good procedure anyway. I'll back off front iso a bit or live with it. Thanks.

Before you throw in the towel, eliminate all the non-iso issues that can cause vibration. 3000rpm and up is when the vibe's are supposed to clear up.

Make sure nothing is hitting. I've seen lots of primary covers with dents worn into them.
Make sure nothing is loose. Side and centerstands can do it.
Check the swingarm for slack. If you roll on the gas or back off at 3-4thou does the vibration change?

For iso problems, you mentioned that you would 'back off' the front. Do you have a set of MkIII verniers? The rubber in them is said to be stiffer than the old parts. How old are the iso rubbers? What clearances are you set at now?

It's pretty hard to describe the benefit of using a link style headsteady. I put 50,000mi on my bike with a Norvil iso headsteady. Great handling but the vibes never completely cleared up. I went to a link type headstedy last year, now I have the best of both worlds. As long as there isn't a problem in some other area causing vibration, a link headsteady, Hemmings adjusters, and old style rubber iso's are about as easy as it gets to setup and get what you expect from the Isolastic marvel.

There really shouldn't be any vibration that can be felt by the rider at any engine speed above 1000 rpm. The total elimination of vibration felt by the rider was the cornerstone of the Commando development. The Atlas had such a terrible reputation for vibration, management felt it was really hurting sales against the much smoother Japanese four-cylinder bikes. The story was that a headlight bulb on an Atlas only lasted 5000 miles and it didn't matter if you switched it on or not. The vibration shook the bulb filament off its terminal posts.

Thanks Bob & frank. I just haven't had time to sort the iso's yet and I am going to the Manx on friday on it. I know it isn't right and will sort after the IOM. It was set to ten thou front and back (with feelers). I have backed off an extra hole today front and back and will see what it's like on the way to the ferry later this week. It has MK3 adjusters. I'm going to renew all ribbers this winter. I could tell on my old Mk1 Commando when the clearances were too wide as it weaved (when thrashing it thro the bends); the hinge effect. This shows no signs of that just vibes.

Will check centre stand bolts. I know it's slighty fouling on the chainguard but the vibes stop when In pull the clutch in.