The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: ambrose78 on July 24, 2009, 10:53:49 PM
-
My bike has developed a bit of a wobble. It only happens if you take hands off the handlebars (not that I do this a lot but when checking for the tracking of the bike). Put the hands back on - wobble dissapears.
It only happens between 50km/h- 80km/h (30-50mph). Below and above this range the bike tracks true.
I've had a look at the tyres (Metzlers) and they appear to be in reasonable knick. No obvious flat spots on either front or rear.
Could this be wheel balance?
-
I'd re-check the tightness of your steering head bearings, but first, check that your tire pressures are up to where they should be (at least 32 PSI -or 2,2 Bar in the front tyre). I once had a wobble in my front tyre that seemed to happen exactly between 40 - 45 MPH. I started looking into head bearings etc, but stopped myself to recheck the tyre pressure... there was only 23 PSI in the front tyre. I normally ride with 35-36 PSI. Pumping it back up solved the problem.
-
Checked the Tyre pressures 32psi in both. I'll try 36psi next time.
How exactly do you reckeck the steering head bearing tension? Will i need to pull the top of the triple clams off?
Otherwise the steering feels smooth, and there is no lateral movement if rocked front brake aplied back and forth.
cheers
-
Try a quick check for correct preload of the steering head bearings. With bike on centerstand and front tire clear of the ground and pointed straight ahead, note how the wheel falls off to either side when encouraged by a gentle nudge.
Wheel does not want to lay over smoothly? Bearings are too tight. Flops over rather briskly and with some impact with the stops? Too loose. This is pretty much what the BMW manuals advise.
You mentioned wheel balance. This is worth checking, too. Doesn't sound serious but little niggles such as this are indicators of... something. All we have to do is find that something. Check back in.
Monte My freshly painted R65 wouldn't start because I forgot to fill the tank Miller :-?
-
If everything checks out then revisit the front tire. I have bought two bikes with front Metzlers that looked great but had a head-shake at about 45 MPH.
-
Replace the tires...
-
Tire pressure, head bearing preload, swing arm centered and bearing preload, rear and front wheel bearings, rims true, wheel balance, drive shaft play, fork alignment, frame not bent from any mishap with crash bars, sliders not binding. Just throwing out anything and everything I can imagine on top of a dodgy front tire.
-
Okay well the steering does have some impact on the stops. I'll tighten the head bearings a little and see if that improves the situation.
The mention of a bent frame is a little alarming. I've had a look near the crash bars bolt on to the loops frame and it appears that there is more room between the engine and the frame on the left side than there is on the right by about 5mm (by eye measurements). Is the engine supposed to be symetrical in the frame? Is this normal for an r65?
-
Hmm. I think that the engine is supposed to be centered and symmetrical about the front frame down tubes, I guess that I haven't measured then to be sure - might it be an optical illusion if the crash protection bars aren't mounted exactly the same? Remember, one cylinder is further forward than the other, which might be messing with your visual image.
-
Well I'm trying to tighten the adjuster nut. It is as tight as I can make it by hand. There is no fore/after play and the steering is smooth but it will still hit the stops "with some impact".
Does it need to be any tighter? And if so what would one use on the knurled adjustment nut to tighten it further?
-
As for the frame - when viewed directly from the front the gap to the engine on the left hand side is larger than the gap on the right hand side. Is this normal?
-
Use some big "Channelock" pliers with a few wraps of duct tape around the nut. As far as spacing I suppose if somebody had replaced the stock steel spacers on your motor mount bolts with the aftermarket rubber ones (supposed to help the 4.5k buzz) they could be deteriorating and letting things flop around a bit...
-
I wouldn't tighten them much further - mine will still make a "clunk" on the stops when nudged to either side, though the wiring loom on the left hand side slows the turn out a bit, and I'm pretty sure the steering head is an appropriate tighteness.
-
I went to the local MC shop and checked the preload on several different brands of bikes as well as BMW for a reference.
You might want to go ahead and service the bearings there if you havent already, it's not that hard to do ...only took me a couple hours and the bike feels more connected to the road and stable for it.
There is a nice instruction thread on the "how to" part of this forum.
The engine to frame spacing on my bike is the oil filter cover side is closer to the frame than the gear shifter side.
Oriented towards the drive shaft side which I am sure is normal.
-
If you choose to torque the adjustment a bit more and get it a tad too tight then the bike will exhibit a "slow speed weave", IIRC. At this point just back off just a hair and re-do the test ride until the "weave" just goes away and you can't induce shake by smacking the end of the bar. When I take my hands off the bar and smack one end (on all my bikes) it will oscillate maybe 2-3 times and then go rock steady. If to loose you'll have to grab hold to get the shake to stop.
At least that's been my experience...
-
I went to the local MC shop and checked the preload on several different brands of bikes as well as BMW for a reference.
I'll try and do that in the next couple of weeks
You might want to go ahead and service the bearings there if you havent already, it's not that hard to do ...only took me a couple hours and the bike feels more connected to the road and stable for it.
There is a nice instruction thread on the "how to" part of this forum.
Indeed there is - I followed it a month or so back - very informative.
The engine to frame spacing on my bike is the oil filter cover side is closer to the frame than the gear shifter side.
Oriented towards the drive shaft side which I am sure is normal.
:) Much releived now. I had been worrying that my frame was bent. Good to know it is a normal offset.
If you choose to torque the adjustment a bit more and get it a tad too tight then the bike will exhibit a "slow speed weave", IIRC.At this point just back off just a hair and re-do the test ride until the "weave" just goes away and you can't induce shake by smacking the end of the bar.When I take my hands off the bar and smack one end (on all my bikes) it will oscillate maybe 2-3 times and then go rock steady.If to loose you'll have to grab hold to get the shake to stop
I'll give that a go.
I wont get a chance to have much of a play with the bike for a couple of weeks as about to head to Jindabine for some work (and Skiing ;D. )
-
For an update,
Still got the wobble.
I compared other bikes steering tension - mine seems comparable so I'll leave it with the current tension.
So next thing I'll check is some new tyres and a wheel balance. Seeing as the wobble isn't a major danger, I'll wait until they wear out. At the moment I'm doing about 800km per week on the Bike the current ones should wear out in about a month or so.
Any reccomendations on tyre choice?
Cheers
-
Hey, Pete Have you checked out Snowbum's article on Wobbles, Weaves, & Tank Slappers? Item #4 in this particular article. Might provide some useful information before you invest in new rubber. Monte
http://bmwmotorcycletech.info/miscl.htm
-
hmmm might be time to do a fork rebuild and realignment.
-
Just an update on the weave - It has dissapeared.
Fitted a set of battleax tyres a few months back and the weave has dissapeared. I've ridden the bike for few thousand kms just to confirm.
Maybe it was the old tyres or the wheel balance causing it. Either way it is nice to ride without the wobble.
-
Pete,
My bike did exactly the same thing and when a mechanic test rode it he suggested new tyre. He also said I check the headset bearings. So I read a FAQ here and I re-greased the bearings and then re-tightened them. When I pulled them apart I found the allen tensioning bolt finger tight but round adjuster had marks where it had been tightened. Also the grease was solid.
So after greasing I did the adjuster up finger tight then did the allen bolt up to 80 Nm only to discover notchy bearings. After many fiddly adjustments I now have it at a point where the handlebars still fall and there is a slight notch near full lock but the bike was a revelation to ride. it is rock solid now.
I know I need new bearings but for the moment it is wonderfully steady. I also have a new tyre now running at 32 psi but it was the headset bearings that were the problem for me.
When the mechanic fitted the tyre his words were, "Well that is a sh*tload better!"
All the best,
Paul
-
The bike is telling you it needs new rubber.
When you get familiar with your machine you will reconised the message for what it is.
Squared off back tyre?
Steve h
-
I got out yesterday 6 march, 4 degree F. to a max of 8 degrees cool but good 150+ km ride overcast and very light rain for less than 1 mile. Except for a moderate wobble coming down from highway speed to city, 60-65 hwy down to 30-40 city mph indicated, uphill/downhill made no difference, only on deceleration, front pressure 26psi rear 36psi front tire older Bridgestone not known how old rear new Kenda very smooth from the rear nothing out of the ordinary there. Steering head is good no notching , no front to rear play and no side to side, bearings are good. Bike is very smooth on the road and tracks very well better than most of the bikes I've owned it's the same around town. I read the article on wobbles and slappers and from my own experience it's right on. It's colder today but clear and I put the tire pressure up to the tire max front and rear 41 front 40 rear and will go out the highway in an hour or so to see if this helps, have to wait for the frost to clear. With the tire pressure lowered to 20 psi there seemed to be no problem but the tracking was harder and steering was mushy/heavy, tire drag probably. Bike has 83,500 KM since new just over 50,000 miles. Rear drive and bearings are all good. One other thing it's just old habit, when coming down off speed I use light braking from the rear only as the disks are just to good at there job . I tried front and rear weight shifts and all this made no difference. Bike has no fairings/bags to throw me about just plain R-65. After reading the wobble/slapper article I checked everything except the tire pressures and found nothing out of place or worn to excess before returning home and the wobble was the same on the home end. I had a friend behind me and he says the tracking seems very true but he was able to see the wobble.
The wobble is not that bad but was a bit of a shock considering how the bike handled on the highway and a round town. It wasn't something I was expecting.
-
You might try 36lbs F/R.
If your bike is new to you, and you don't know when the tires were installed, you might want to consider a fresh set. It is like night & day.
-
You might try 36lbs F/R.
If your bike is new to you, and you don't know when the tires were installed, you might want to consider a fresh set. It is like night & day.
I did that with the rear and the front is on order but the wobble is gone with just taking the front tire air pressure to the tire maximum and doing a test drive. Overall I'm impressed with the 30 year old red headed step child of BMW'S (no offense to red headed step children intended) it's really very well put together. For long distance cruising the seat will have to be addressed or use the full length sheepskin, I have that comfort item....when I'm all done changing and balancing the tires then I'll lower the pressure in 3 lb increments till I can reproduce the wobble and then stay 5-10psi over that. Then the whole thing changes when the sidecar is ready and installed
-
I think proper tire pressure is when they inflate 10% over cold when warm.
I tried EVERYTHING to make my original seat as comfortable as it was when it was new. Nothing worked. I even had the seat refoamed.
A new, reproduction seat from S. Meyer solved the problem.
-
I think proper tire pressure is when they inflate 10% over cold when warm.
I tried EVERYTHING to make my original seat as comfortable as it was when it was new. Nothing worked. I even had the seat refoamed.
A new, reproduction seat from S. Meyer solved the problem.
There's probably nothing wrong with the seat it's more likely my tired old sit upon. I have access to a /5 LWB Corbin but I'll go for a 1400 miler first then decide. The object here is to enjoy the heck out of it without spending a fortune on replacement parts and be able to fix it on the road with a pocket knife and a nail file only if it's needed. It's really nothing to look at but it runs very well for a 30 year old bike. The RPM at highway speed could be lower for economy reasons but I'll live with it unless a rear drive unit comes my way, 32/9 or 3.56/1 final is truck gears. 32/11 or 2.91/1 final would be more desirable for economy (one day maybe)
-
Replace entire front end with one from a 1988 K100RS (either with or without ABS).
Your results may vary! :D
-
Mine has a slight wobble at about 50-60kmh. Mine is because I hit a rock and now a slight buckle in the rim. Spare front rim still sitting in the carport waiting for me.
-
Update
Replaced the rear tire (not that) but it needed it anyway, got the new front today but was out riding and the rear got a really weird squishy feeling from the rear, wobble was way worse. Entire front end is good (old tire,shocks,triple tree's, head bearings, all checked out good). The squishy feeling came from an off angle curb and a poorly adjusted rear swing arm. Torqued everything to specs and went for a burn now it corners like a real bike instead of falling off in a corner no more wobble on deceleration. One of the swing arm lock nuts was under torqued and the bearing preload was off as well. Sometimes a wobble can come from the rear and be shifted to feel like it's coming from the front. Glad I found the problem and had a friend with the proper shaved down socket, now I'll have to make one for my kit. Three weeks to find and 10 minutes to fix cost nada....Getting to really enjoy this red headed step child over 500 miles so far bring on the twisties.
-
Out again on Sunaday with friends and came off highway to a 4 way banked left and when I went to straighten up the bike after the turn bike took a very nasty turn to the right and almost put me in the park like the steering was locked. I came home and rechecked the head bearings and snugged them up and went for a very short ride it was way worse, almost lost it again. Returned to loosen the bearings and came 1/4 inch looser than it was in the first place and all the problems no seem to have gone but still no bearing slop or excessive play. I ordered new bearings take a week to get here, coming out of a corner now gyro's back to upright and corners way better slow speed has also improved over what I started with. Putting a K front end on it is out of the question just getting it back to stone stock would be nice for 30+ on 26-27th of last month its a heck of a machine I should have bought one in the mid 60's to early 70's I'd probably still have it but with a lot more than 84,000 K's or 51.000 miles. Hardly broke in yet.... I think I'll keep it as my last ride. (Very slow learner)
Close to 20 years with little to no maintenance it just takes time to go over it all, the weathers to nice to early to stop now so it's running maintenance for this year and total paint over the winter I should get over 9 months out of this year that's not normal for here as I'm only 90 miles from Alaska as the crow flies.
-
like the steering was locked.
I know exactly what you mean - scary stuff when not expecting it.
If your bike is in a condition similar to mine then it probably has the original factory grease which will have/be going hard.
At first the steering gets a bit stiff and it makes you think you are having an unco riding day. Then it starts to jam at certain angles.
Service those bearings is my advice. There are some guides on here for reference. Be aware the centre Allen bolt on top of the triple clamp will need a good quality strong and long wrench and possibly a breaker bar or extension of some sort to 'crack' it - it's handy to have someone to hold the bike at this point. Other than that the job is pretty straight forward and takes and hour or two muddling around in the garage.
In the Interim/ and or for diagnosis purposes there is a little hole usually with a flimsy dust cap in the head tube behind the headlight - squirt some wd40 or similar loosening oil in. The steering should free up considerably and stop locking in certain positions.
That should get you by for a week or two if you don't have the time immediately but test it at low speeds in a safe spot first.