middling speed wobble

[ambrose78]

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 . )

[ambrose78]

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

[montmil]

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

[ambrose78]

hmmm might be time to do a fork rebuild and realignment.

[ambrose78]

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.

[plc]

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

[steve hawkins]

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

[bubby-joe]

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.

[Rob Valdez 79 R65]

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.

[bubby-joe]

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

[Rob Valdez 79 R65]

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.

[bubby-joe]

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)

[Semper Gumby]

Replace entire front end with one from a 1988 K100RS (either with or without ABS).

Your results may vary!  

[Darwin_R65]

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.

[bubby-joe]

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.