Wobble Baby Wobble

[JPSpen]

Well the new tires on the R65 are nice, BUT, Like the old tires, If I get above about 60 she starts to wobble... Then you have to slow down to get her back under control....


Any Ideas where I should start looking?.. The new tires are Shinko 244's..And I'm going to take them off and check the balance again...

It seems to me that the frame is really flexing and causing this...

Any input on this would be appreciated...I'm going to pull the tank and start looking for broken welds and what not...

'82 R65 23K miles...

John

[Bob_Roller]

Are the tires seated all the way on the bead, there usually a guide line on the sidewall to indicate the tire is properly seated .

I'm only familiar with Metzeler tires, the guide line is a very fine vertical lines .

[montmil]

Couple other ideas...

Steering head bearings may be slightly loose.

Preload on rear wheel bearings set incorrectly.

Worn wheel bearings either front, rear or perhaps both ends.

Rear shocks gerfunken. One or both.

Spring preload set differently on one shock.

Swingarm pivot bearings loose or worn.

Incorrect volume of fork oil or collapsed springs.

OK, that's more than a couple, but all can be checked without spending a nickel. If the bike had a speed wobble with the old tires and it's still there with the new rubber, I might rule out the tires as suspect.

[nhmaf]

I'd verify the tires were properly mounted ont the rims, and, barring anything incorrect found there, proceed down Monte's list.

sometimes the wobbles observed at the fron tof the bike actually originate toward the rear.

Also, what air pressure are you running in your tubes?

[JPSpen]

Running about 34 front 38 rear as far as pressure..
Tires are seated...

I can make it knock it I hit a good bump.. I'll check the steering head bearings..

Rear shocks... Guess I better check them too....I can see a difference in preload causing an issue...

Starting down Monte's list..

thanks for the input..

John

[tvrla]

The rear shocks usually need to be set on the lowest preload setting for solo riding. I can barely get enough sag - but then I'm not too heavy at 160 lbs. The Konis come with springs that are too stiff. I got some lighter ones and am very happy with how they feel.

The rear shocks have a direct effect on the steering geometry, so don't discount the importance of setting them up correctly.

[montmil]

Just one of several reasons I highly recommend the Hagon shocks sold by Dave Quinn is that Dave takes plenty of time to ask multiple questions about his customer's wants and needs; including their weight -dressed and ready to ride. That's good customer service.

http://www.davequinnmotorcycles.com/

[JPSpen]

Yeah, The Koni's are on their lowest setting and still pretty damn stiff..
Can't really collapse the back end much....I would think that since they're not doing too much moving around that they wouldn't be the issue... Something is starting an oscillation that's being made worse by the frame flexing...

I'm going to try putting some weight in the rear cases and see if that helps any.. I have an 80 lb bag of concrete I can put on the back if I need to.. That'll look funny going down the road...

John

[Barry]

I can make it knock it I hit a good bump.. I'll check the steering head bearings..

There has to be some slight pre-load on the steering head bearings. An absence of looseness on it's own is not enough.  A small amount of pre-load will help damp out any induced steering oscillations. There's a fancy BMW tool and method for setting the pre-load but I think most people get good results setting them so that there is some perceptible drag with the bars still free to fall side to side but not too rapidly.  It will be obvious if there is too much pre-load as that will induce a slow speed  weave as each steering input is over corrected for.

There can be other causes of a knock over severe bumps though so it's not necessarily a symptom of loose head bearings.  

Just thinking about your rear cases. Is there any difference with them mounted or not ? I know you shouldn't get a wobble at 60mph regardless of cases but they might make it worse.

[Bengt_Phorqs]

Before you test the concrete bag, check the swingarm spacing and swingarm bearing preload.  It is amazing how that can affect front end handling.  

Other than that, everything the others say about steering head bearings and front wheel bearings.  Just one bad front wheel bearing will cause the wobble you mention at higher speeds.

[montmil]

I'm beginning to lean a bit further toward worn, loose or maladjusted (like me) swingarm bearings.

They may not be worn out, but if those tapered roller bearings get a little loose or 'settled out' of preload specs, the bike will wobble as bad as me n' Mike leaving the Barber swap meet.

It was warm. We were thirsty. We found bargains. [smiley=beerchug.gif]

[Matt Chapter]

It was warm. We were thirsty. We found bargains.  

They call that a "Texas Summer."

I'm seriously considering resurrecting my kegerator!

[tvrla]

Yeah, The Koni's are on their lowest setting and still pretty damn stiff..
Can't really collapse the back end much....I would think that since they're not doing too much moving around that they wouldn't be the issue...

What's the sag? I've found the Konis come with springs that are way too stiff. They're spec'd for the same springs the larger beemers wear, and they're pretty stiff on them as well. I'm running shorter and lighter wt springs and love them. Don't recall the number but think they're 222.

It's possible the front sags and the rear doesn't, giving you steep front geometry.

[JPSpen]

The front had a Vetter fairing on it too.. So I'm wondering if the springs were beefed up for that...

But I can push down the front pretty easily... Haven't had time to fool with it much since I have other bikes to ride...

And I'm building a trailer....Look out Arkansas....

John

[bruce_launceston]

So it wobbled with the old tyres and the new ones, I'd put my money on the fairing contributing to the wobble possibly with loose or worn steering head bearings.

Try it without the fairing.