Bike pulling left

[centaurus]

I have a strange problem on my bike - '02 busa: when taking hands of the handlebars, the front wheel turns left. In order to run straight with no hands I have to lean the bike to the right quite a lot. If it use the front brake the steering and the bike straightens back up.

Things I have already checked:
- replaced steering head bearings in the meantime - no difference
- replaced tyres in the meantime - no difference
- I am sure I run the correct tyre pressure
- checked rear wheel alignment
- checked front brakes - no dragging
- ran without steering damper - no difference
- loosened up the triple clamps, bounced the bike up and down a few times and tightened them up to make sure they are parallel to each other.

I haven't checked;
- frame straightness; however, there are no scratches on the frame to indicate an accident
- forks straightness

Lifting the front of the bike up, it seems I can turn the handlebars to the left easier than to the right but the difference is so small, I might be mistaken. If this is true, I am thinking the cause might be the cables and wires going to the handlebars, but all of them are routed correctly according to the manual.

Any ideas? I don't want to spend hours and thousands of $$$s dismantling the bike and getting the frame checked unless I have exhausted all other possible causes.

[Gremlin]

Not to sound like an annoying idiot, but have you checked you're definitely not sitting out of balance on the bike, ie, I've noticed I sometimes sit to the left of centre on the bike. As it starts to move one way, you often put weight on that peg to try lean the other way, increasing the effect.

Alternatively, any particular loading on the left of the bike?

[Bren]

tell it to "Straighten up and fly right"

[NighthawkNZ:Me]

Things I have already checked:
- replaced steering head bearings in the meantime - no difference
- replaced tyres in the meantime - no difference
- I am sure I run the correct tyre pressure
- checked rear wheel alignment
- checked front brakes - no dragging
- ran without steering damper - no difference
- loosened up the triple clamps, bounced the bike up and down a few times and tightened them up to make sure they are parallel to each other.

I haven't checked;
- frame straightness; however, there are no scratches on the frame to indicate an accident
- forks straightness

steering head bearings check...what about wheel bearings? even swing arm bearings?
checked rear alignment... also check front
quick check on fork seals if one is leaking and low in may make it pull...?

[BuzzardNZ]

road camber? I thought I had a similar problem, but turned out to be that that road I was on had a particularly high camber to it. Does it only happen at speed?

[marty]

i'd call road camber too. my busa always did that too - it's such a long wheelbase.

[Robert Taylor]

Many many mass produced bikes of all brands are not perfectly ''straight'' and I can recall a few years back the front wheels on XZ Yamahas being up to 15mm off line compared to the rear!
In overseas first world countries its not uncommon when bikes are raced to send them to the chassis straightener straight out of the crate.

[nodrog:Me]

Id be checking the alignment of the rear wheel before I checked anything else.

Fanny

[Reckless]

Id be checking the alignment of the rear wheel before I checked anything else.

Fanny

He already has miss fanny LOL!
But don't check it off the positioning marks or even with a vernier off the adjusting blocks to the rear of the swing arm (as I do most of the time) usually get it to within 1/2 a mm. I never trust the stamped alignment marks. Do a check from the ¢ of the main swing arm bolt to the ¢ of the rear axle to make sure of alignment. Then check the alignment marks to confirm. That will ensure your wheel is true in the swing arm.

OK another thought have you had a new tyre or puncture lately make sure they have mounted the front wheel/axle properly in the forks and/or the spacers etc are correct in the rear. Cycletreds once didn't fit my front axle on the old Z1R properly and I got tank slappers at 120K took me ferkin ages to figure it out.

Just a few Ideas Good luck!

[AllanB]

Maybe you are just very well hung and the extra weight on one side is putting the bike off.


String-line both wheels to check alignment.

Does it go around one corner better than the other - ie left better than right or vise versa?

[Kornholio]

Hmmm so your bus pulls to the left..... Make sure the passengers are evenly spaced on both sides and tell them to sit down

[F5 Dave]

. . I never trust the stamped alignment marks. . . .

+1 & then some, 'specially on a Suzuki, I've never had one that the marks have been near right.

Long straight edge, heaps of info on net on checking.

As far as road camber goes: you can check on a long deserted road in the middle of the road.

[davebullet]

Is it slow speed or countersteering speed phenomenon? Does it get worse the faster you go?

I wonder if it is a cable pulling thing.

What if you drop it into neutral and let it coast without drive train involved? Could it be engine torque somehow twisting the bike and turning it?

[centaurus]

Thanks for all your replies guys. To answer a few of your questions:
- it doesn't get worse with speed - it's almost the same at all speeds
- I've tried on different cambers so it's not the road camber
- if I hold the steering straight the bike goes straight, but the handlebars keep wanting to go left.
- Lefthand corners are more difficult to take because the front wheel keeps wanting to steer in the corner and lift the bike up, but if I keep the pressure on the handlebar to keep the wheel straight it goes around the corner ok.
- I have measured the rear wheel alignment from the swingarm axle (the notches on the swingarm are not aligned).
- Head bearings have been replaced and adjusted twice after being replaced and it made no difference.
- I know it's not a matter of leaning on one side of the bike because if I take my hands off the bars, in order to keep the front wheel steering straight I need to lean the bike to the right and lean myself to the left on the bike to counterbalance the bike.

given that when holding the bars straight the bike tracks straight, can I exclude bent forks or bent/missaligned frame?

[Reckless]

Shivers mate sounds like you've checked all things that any normal guy can check and I'm a panelbeater by trade. IF I had to take an "internet" guess I'd say its in the front somewhere from your last post????

My only other suggestion is to take it to the guys that certify a bike that's been crashed and de-registered then fixed. They have the equipment to check the chassis and probably a lot of knowledge in this area.

My guess is its something very simple you have missed like an unseated axle or its bent somewhere.
Good luck let us know how you go!