Handling badly?

[beemer]

Hi Everyone,just come back from a 122m ride out today,weather is really hot here in West Wales!!problem is,my bike is not handling well at slow speeds,10/15/20mph,it's hard to keep in a straight line!!it wavers all over the place,is it my bad riding!wrong tyre pressures?,wheel alignment?swing arm bushes?please help,i really don't like it like this!!thanks,so much,J

[montmil]

Mine will "wander" at low speeds like a kiddie car... if I forget to set the rear shocks for the current load. Shocks cranked up for two-up and traveling loads will definitely make you doubt your riding skills if you're solo.

Why were they set so very firm, you inquire? Getting that danged rear wheel off. Or trying to.  

[beemer]

As far as i can tell they are at the softest position?if you have a pic of how they should be set for solo riding i would be most gratefull to see it,thanks,J.

[MrRiden]

Beemer,
There are a bunch of reasons you might have this problem. The obvious, low tyre pressure, worn shocks, improper fluid / level in the forks, loose / worn wheel bearings, improper swing arm bearing adjustment but I remember reading somewhere that overly tight / stiff steering head bearings are a common cause of low speed weave. Easy 'nuff to check. Throw the bike up on its center stand and with the front wheel off the ground and the handle bars centered you should be able to nudge the bars in one direction or another causing the wheel to turn {fall} fully under its own weight. If it binds or does not fall to lock see the suecanada article
http://suraklyn.com/yabb/YaBB.pl?num=1189357717
rich

[montmil]

Rich has given you a lot of choices... all good possibilities. Have you recently altered/changed/tweaked anything he mentioned?

Do the easy checks first; ie: tires, fork juice, steering head "tip off". Then, step up to the more labor intensive checks.

A suggestion here, from the voice of experience and/or screw-ups... Tweak only one thing at a time and then test ride your scooter. Change more than one without a follow-up ride and you may never know what the problem is/was.

Luck to ya [smiley=thumbup.gif]

Monte

[beemer]

Thanks to all for the info,i did change the fork oil recently,but it feels like the back end is unstable to me,i will go through it one by one and hopefully sort it out,cheers,J.

[Semper Gumby]

I vote wheel bearings or swing arm bearings.  Wheel bearings should be checked everytime you replace a tire or about 10000 miles.  Surley no later than 20000 miles.  They are not sealed and they must be cleaned greased an re-installed.  Replace the dust seals when you do this as well.  I noticed my front bearings going baad when I could "hear" them starting to 'roar'.  Not good.  Should be easy to hear and see with the bike parked and the front wheel in the air.  If there is any play at all - fix 'em.  

After that grab the front forks and rock 'em forward and aft and see if there is any play in the steering head bearing.  

Check the swing arm bearing and set them on the high side of the range (I can't remember what the book number is but its a small number.)  The tighter they are set the less the bike wobbles at high speed.

Back end:  Low rear tire pressure or rear axel loose.  Could be bearings as well.  What does the oil in the final drive look like when it comes out?  Is it clean or is it dark dirty or chocolate mocca?  Do you hear any grinding / crunching sounds when you spin the rear wheel?

Good luck.

[DgM]

My 1983 r65 is handling a bit dicey - constant speed over 45mph slight wobble over road imperfections, around corners over 50mph tracking poorly - not a mess, just enough to reduce confidence.  While under acceleration, handling is better, tighter. Would this indicate swing arm bearings worn out?  Or wheel bearings worn out?  The steering head bearings are tight and smooth.  Can swing arm bearings / wheel bearings be checked without disassembly?

[beemer]

Iv'e checked my rear wheel bearings today,and the head bearing is fine also,tomorrow i'm going to check the swing arm bearings,in the Haynes manual it says to put the bike onto the centre stand,and holding the bike firmly see if you can feel any play in the swing arm bearing,if you can,you can adjust it,you need a 27mm socket and a socket fit allen key,your supposed to slacken the 27mm nut,and torque up the bearing using the allen key adjuster to 15lbs,then slacken it off,and finally torque it to 7.5lbs,also you should measure the distance from the swingarm to the frame on both sides to make sure it is central,all this info is from the Haynes manual,i also made sure my tyre pressures were 28 front and 26 rear,again taken from the manual,this is for solo riding,i did find that the spindle nut on my rear wheel was too tight,iv'e now set it using my torque wrench to 35lbs,the only thing i could hear with the front end was a sqeaking as one of the cables rubbed on the frame,but the steering did fall easily to both sides so i was happy about that!!!i'm just doing a job a day and test riding it afterwards to see if it improves,i think tyre pressures were my problem,the bike is handling better since i used the correct pressures,it was set to 2 up riding before,it's worth getting the haynes manual, and i also bought a re-print of the BMW workshop manual,and hopefully between the 2 it should tell you what you need to know,hope this has been helpful,i was certainly helped by the other guys with much more knowledge then me on here,cheers,J.

[MrRiden]

Beemer,
So far so güt! A note about the 27mm socket. A good number of brands will not be able to fit in the recess for the swing arm nut. I picked one up at the local Automotive chain superstore [ ignoring the display of bikini girl air fresheners] and set it up in a drill chuck. Applied a file to the outside edge and in a few I had a handy thin wall socket that could reach into the recess and grip the nut. You might want to see about some type of needle / tube grease gun to lube the swing arm bearings if you don't already have this stuff.
rich
who has a serious tool habbit.

[Bob_Roller]

You should increase your tire pressures, I was using the same pressures as you are, and when I relaced the original Continental tires that the bike came with, to Metzeler tires, I had handling issues until I increased the pressures to about 35 psi.

Also how accurate is the tire pressure indicator that you are using, I had one read 9 psi high !

[MrRiden]

I'll echo Bobs post. I'm runnin' some Chinese tires and the upped air pressure helps but for me mostly at higher speeds.
YMMV
rich

[Justin B.]

Bob is right, the tire pressure recommendations in the manuals were for tires manufactured with thirty year old tech and outdated material - at least by today's standards.  If the front gets less than 32 PSI on any of my bikes I can damn sure feel it.  I try to keep about 38 rear and 35 front, when handling gets squirrelly I know it's time to "top-off" the pressures...

[nhmaf]

I am also running my front & rear tires somewhere between 32 -35 PSI (BT45 tires) and it handles very well.

Have you checked the fluid in your forks ?   Perhaps wouldn't hurt to drain and replace with proper amount of
fresh in each leg - a significant mismatch of fluid in each leg can cause weird handling issues.

[Rob Valdez 79 R65]

I am sure it is your low air pressure.

35 - 35 for me, too.

beemer, a lot has changed in tire technology since the handbook was printed.  There may be a sticker under the seat on the rear fender that gives this (misleading) information, as well.

Let us know how it feels.  And I forget if you already told us, do you still have the original shock absorbers on the rear?  If so, they need to go, now.  There are affordable, decent replacements, as well as high-dollar, higher performance shocks.  But the originals, easily recognized by the very handy built-in adjuster handle, were not very good straight out of the dealer's door, they say.
Refreshing the oil in your forks may have been enough improvement for you to notice failings in the rear suspension?