The New And Improved Unofficial R65 Forum V2
General Category => Chit-Chat => Topic started by: JPSpen on June 19, 2012, 06:33:13 PM
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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
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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 .
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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.
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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?
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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
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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.
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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/
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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... :D
John
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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.
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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.
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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]
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It was warm. We were thirsty. We found bargains.
They call that a "Texas Summer."
I'm seriously considering resurrecting my kegerator!
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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.
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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
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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.
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Fairing was off when I got it.. I saw no need to put it back on..
I already have two fully faired bikes...And the GS with the popeshield..
I'm getting close to wrapping up this motorcycle trailer project.. Then I'll have a look at the back end.. I agree on the rear end causing apparent front end issues...
I'll be checking and resetting the swing arm and all the bearings..
John
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Update.. It finally cooled off enough for me to get a good look at the R65.
OMG !!! The swingarm moves back and forth almost 3/8 of an inch...
Anybody know what size the socket is for the swingarm.. I thought I had one but none of mine will fit...
Thanks
John
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You need a thin wall 27mm socket or a standard socket can be modified to fit. As well as reducing the wall thickness so that the socket fits into the frame aperture, grind or turn the end face down to remove the lead in chamfers. This ensures the socket get a good purchase on the thin lock nuts.
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So, While several folks guessed the problem might be the swingarm.. Nobody would ever believe this unless they saw it with their own eyes...
There was a 10mm nut in the grease between the adjuster and the wall of the swingarm keeping the adjuster from being tightned far enough to load the bearings...
BMW of OKC last had this apart for a clutch... So you know the mechanic just said F'it....
This is why I work on my own stuff...Jeez...
Does the swingarm just center up between the two sides ? or is the spacing greater on one side ????
Thanks
John
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... Does the swingarm just center up between the two sides ? or is the spacing greater on one side ???? John
Gaps between swing arm and chassis should be equal. Drill bit shanks can be useful measuring "sticks".
You will need to use a pair of ViseGrips or similar to hold the 27mm socket while the correct size Allen wrench can pass through the socket and snug up the pivot pins. Little bit on this side... little it on the other... ad infinitum.
Once you're equidistant with the gaps, start snugging up the 27mm nut. This may require a few attempts. Use the Allen to keep the pins from moving.
Monte
Still fighting the remnants of a two and a half week bout with pneumonia
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The wobble is gone.. Bike rides as it should now...Completely different from the way it was... Even when it didn't start to oscillate, It was still pretty squirrelly at times.. All that is gone now...
Pegged the speedo....
What a fun little bike...
John
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Hi John,
You are not going to like this much but...
With the Vetter fairing (and side panniers?) on, you have overloaded the bike. You can help things by going down Monte's list but the simple fact is that the front forks are not stiff enough for the added weight of the Vetter on the front end.
I went through all of this on my R65 10 (?) years ago. I tried everything: Telex front fork brace, 100/90H18 rear tire monted on the front, setting the pre-load on the rear swing arm bearings to the maximum torque allowed. Nothing worked. My bike would start to wobble near 65 mph. I was going to send my rear swing arm to SanJose BMW for bracing when I gave up.
So what cured this? You have two choices. Remove the Vetter or bolt a K100 front end on the front of the bike. It has larger diameter front forks and 18" rim that is 2.5 inches wide. The bearing numbers are the same for the R65 and the K100. Try to get a solid mount K100 top tripple tree. The early ones had rubber anti-vibration handlebar mounts that make braking "interesting".
The R65 was designed to be a Nekked bike (yes I know there were few European R65RTs.)
FWIW - With the 1988 K100 front end is rock solid at 90 mph (downhill with a tail wind) and the steering is greatly improved at speeds above 50 mph.
There are two types of K100 front end: standard and "S" sport forks. I didn't plan it this way but I ended up with the Sport forks. The "S" is stamped on the top of the forks on the nut.
Good luck.
PS - My old R65 front end is about to go on a BSA Hornet Cafe bike.
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Ah you removed the fairing - Good for you!
I use a 4mm allen in accross gap between the the frame and the swing arm to center the swing arm in the frame. I push it side to side until the amount of play is the same in each gap.
I hate to say it, but I wonder what the BMW mechanic did to the clutch? What year is this bike? (fingers crossed) :-[
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The clutch and seals were done late 2010.. I picked up the bike early 2011 and returned it to stock...Rode it a couple of times and then replaced the tires.. After the tires it was still funky and that's when I discovered the swingarm wasn't right....
She's good now...I've put more miles on her this week than the last year and a half...
John