Another wheel alignment question

[desilva]

Hi folks,

I just searched the forum for "rear wheel alignment"and picked up loads of helpful info already, but I'd like to check something. My bike goes straight and well except on fast right-hand bends when I sometimes get a weave set in at the back. It's quite mild, but rapid, and certainly a bit disconcerting. It seems to get more pronounced as I lean the bike over.

My rear wheel is aligned according to the marks, but when I look from the back of the bike the wheel looks like it's twisted to the right. I'm sighting down the headstock/tank/grabrail, but it's diffcult to be sure because the engine covers are asymmetric as as the footpegs. I'll check out the alignment using the techniques I've read about in some other threads, but I'm wondering if it's supposed to look like that (optical illusion 'cos of asymmetry?), and if it is out of alignment, could that be causing the weaving on r/h bends?

[bucks1605]

Measure the distance from your rear axle to the end of the swing arm on both sides.

[natedawg120]

Measure the distance from your rear axle to the end of the swing arm on both sides.

+1, that marks/adjuster on the stock swingarm aren't really there to be trusted, a tape measure works great though lol

[ohgood]

Hi folks,

I just searched the forum for "rear wheel alignment"and picked up loads of helpful info already, but I'd like to check something. My bike goes straight and well except on fast right-hand bends when I sometimes get a weave set in at the back. It's quite mild, but rapid, and certainly a bit disconcerting. It seems to get more pronounced as I lean the bike over.

My rear wheel is aligned according to the marks, but when I look from the back of the bike the wheel looks like it's twisted to the right. I'm sighting down the headstock/tank/grabrail, but it's diffcult to be sure because the engine covers are asymmetric as as the footpegs. I'll check out the alignment using the techniques I've read about in some other threads, but I'm wondering if it's supposed to look like that (optical illusion 'cos of asymmetry?), and if it is out of alignment, could that be causing the weaving on r/h bends?

You want the rear wheel inline with the FRONT wheel, most importantly. This is assuming the frame is straight, swingarm bushings aren't shot, and the forks are straight. Any other way is just -hopeful- to get things tracking proper.

Put the ibke on the center stand, or have a helper sit on it, to keep it level:

Tape a string to your rear wheel, so that you can pull it taught to either side of the front wheel, with it JUST touching the forward part of your rear wheel. You can then measure the distance from the front wheel to the string on either side of it. If it varies more than 1/16th (i mean, if you can tell) you want to loosen the rear axle, and adjust the rear wheel.

Re-torque your axle, and go around the block, then do the string test again.

You could also have flat spots on your tires from sitting too long, or the tires may be shot.

Alignment is key to smooth leans and tire longevity, rider comfort, all that jazz.

(there are better tutorials, even videos online everywhere if you google for 'motorcycle string alignment')

[ajaxgs]

Measure the distance from your rear axle to the end of the swing arm on both sides.

+1, that marks/adjuster on the stock swingarm aren't really there to be trusted, a tape measure works great though lol

that is the fastest way to do it!

[scratch]

It's quite mild, but rapid, and certainly a bit disconcerting.

Mild, but rapid, makes me think it's wheel balance.

It seems to get more pronounced as I lean the bike over.

Again, wheel balance, but could be tires or too soft rear suspension.  Possible inadvertant, or unintentional, rider inputs.  Can you flap your arms like a chicken while leaned over like that?

could that be causing the weaving on r/h bends?

It's only happening on right hand bends?  This sounds more like rider input to me.

Check the wheel balance first.

[desilva]

Mild, but rapid, makes me think it's wheel balance.

Ooh, there's something I hadn't considered.

Can you flap your arms like a chicken while leaned over like that?

Why, will that help me go faster?    I see what you're getting at there. I'm not locked out, in fact I think it was most noticeable when I was in a crouch, feet back on the pegs in my wannabe-gixxer pose, so my elbows were bent but may not have been relaxed. 

It's only happening on right hand bends?  This sounds more like rider input to me.

I can't rule it out, but it's something I can certainly be thinking about. I just checked the wheel alignment and it seems ok so it's not that. It is only on right-handers, or at least that I've noticed it. I wondered if the camber of the road was having an effect - being in the UK I'm riding on the left, so a right-hander means I'm off-camber.

Today I took both hands off the bars on a level road and the bike consistently fell to the right and began to turn. Is that normal for a GS?

[bucks1605]

Today I took both hands off the bars on a level road and the bike consistently fell to the right and began to turn. Is that normal for a GS?

I don't think so, at least from my experience it's not normal.

[ohgood]

Mild, but rapid, makes me think it's wheel balance.

Today I took both hands off the bars on a level road and the bike consistently fell to the right and began to turn. Is that normal for a GS?

OK, that ^^^ is a scary factor of 20,000 or so. It's time to park le bikie and find the cause.

Here are two links to how stuff can/should be checked. I can't find jack on gstwins right now, but i have these saved from the kind folks over at another fine 500cc forum:

http://www.ex-500.com/index.php/topic,148.0.html

http://www.ex-500.com/index.php/topic,276.0.html

If you'll notice, there's a f.o.g. (i won't spell out what that means, but you can guess   ) guy over there, that knows stuff, and quite a few others. Their forum is allot like ours. Good folks, good bikes, good times, good wrenchin

Check the tutorials out, and stay off the road for a while till you've got it nailed down, aight ?

[qwertydude]

If I ride with no hands and my bike pulls to the side that tells me alignment. I check mine using a chain alignment tool but have since found an even more precise way. I take a long metal ruler place it flat against the rear sprocket and where it ends in the middle of the chain should still be parallel with the inner plates of the chain, even a little off will cause the bike to pull. I find the difference between my hash marks on the swingarm is about 3/4 of a hash mark, a significant difference. And yes my frame is straight.

[desilva]

Ok, now I'm officially worried. What I didn't mention is I had to untwist the front forks after the bike got dropped on it's left side during an attempted theft. I had to replace the bars too, which got bent in the process of breaking the steering lock. 

I've done pretty much everything described in those two posts already (great links btw) to set the wheel alignment and tweak the forks, but I'm going to work through it again. Maybe something has slipped back.

[groff22]

This video explains: http://youtube.com/watch?v=RBxK-OQ--fg

[desilva]

Ok, I'm getting to the bottom of things now - literally. Everything is straight and true using all the methods described above...except that the front wheel is pushed out to the left when looking from the front. It's only out by about an inch at the axle, but you can see from the front that you can see more of the frame to the right than to the left. This must be because of the drop.

My next question is how easy is this going to be to fix? My fork tubes aren't bent, and there's no paint cracking around the headstock so I don't think the frame is twisted (and would that happen in a zero-speed drop?). Bent axle? That's easy to check, but I'm not so confident I want to pull the forks apart.

A mechanic has suggested that the damper rod bolts get bent easily when GS-type bikes fall over... does that sound plausible?  I wouldn't want to tackle that myself, but I do want to be sure I've exhausted all the simple options before throwing myself on the mercy of the shop.

[lilbill]

I don't know if a bent damper bolt  (#16 here: http://fiche.ronayers.com/Index.cfm/Module/Main/TypeID/26/Type/Motorcycle/MakeID/2/Make/Suzuki/YearID/48/Year/2007/ModelID/7551/Model/GS500F/GroupID/357800/Group/FRONT_DAMPER_) could cause the type of misalignment which you are describing...but I'm not an expert. 
That really sounds like the forks or clamps are bent.  You might try loosening the triples and resetting the forks and very carefully checking for a bend in the tubes a small problem at the top is magnified at the end of the tube.

Another problem could be if your fork brace (#3 here: http://fiche.ronayers.com/Index.cfm/Module/Main/TypeID/26/Type/Motorcycle/MakeID/2/Make/Suzuki/YearID/48/Year/2007/ModelID/7551/Model/GS500F/GroupID/357801/Group/FRONT_FENDER_) is somehow damaged it might be forcing the forks to be misaligned.  If you are suspicious of the brace someone here makes custom ones and should be able to provide the correct dimensions.

Good luck