Mk3 Strange Vibration, an Iso question

Yes I understand.
It would seem that the most un obvious thing can lead to a vibration.

hobot and Bob, your advice is much appreciated. Thanks, I will report next weekend when I can ride and test it.

graeme

Graeme,

"magic carpet ride" that doesn't exist ???

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It does exist and like all frequencies anything can upset it. An over advanced ignition or poor petrol can cause it too.

My old Mk3 is going through a purple patch right now I only get a light patter through the pegs at 2000 then she smooths out. However if I ring her neck I can feel she's working.

Keep trying you'll get there.

Best of luck.

Cash

GRM 450 said:

Hmm, I will get Inspector Clouseau on it !

New, tyres, wheel bearings, head stem bearings, fork bushes, etc.

The head light was loose, the fender was ok.

I'll be pissed off if all this is caused by a loose headlight !

Things that make you go Mmmmm !

When I said the vibe goes away by pushing on the bars, I don't mean by pushing lightly, but pushing hard. Can't do that for long.

graeme

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everything tight in the triple trees? was the bearing spacer tube tight when you replaced the bearings? Seems like if it goes away when you push on the bars it'd definitely be coming from the front end

There's more possible causes?

Cash, I did advance the ignition a couple of degrees as it felt as though it would get to 3800 revs happily and with some urgency then it had to be pushed above that. (pazon ignition)
It didn't seem to make much difference.
Fuel is BP 98 and fresh, always good fuel with no ethanol. (maybe it's too high a grade? )

Pelican, if you mean the spacer between the steering head bearings that press the bearing inners when the nut is tightened, yes that fitted correctly.

This thing has 18 inch wheels fitted if that has any affect ?

I will keep trying and hopefully find what is causing this vibe, and hope it doesn't just dissapear without knowing what is causing it.

Thanks all for your ideas,

graeme

Front tire and its size and profile or wear can indeed mess with vibration, but mostly only hear 18" front limiting lean angle not handling or smooth sense.
I'm pensive my next rebuild on Trixie may lead to same annoying unknown vibe intrusion. I've learned about more sources to beware of on this post.
One thing rider Patton is holding out on is the extra level of inertial smoothness his rear linkage provides. I'm avoiding that on Trixie just to have a test of me and her to get the flying carpet sense the old school way. I've no intention to press her power or road holding - just sane delicious Commandoing around much as I can.