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]

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]

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. :shit:


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!

[F5 Dave]

Pity F1 engineering is so far away in Cameltron. I have a bike I'd like to get checked on their jig too.

[jellywrestler]

unbolt the sidecar and go for a ride

[Toaster]

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

Only happens when both wheels are touching the tarmac.:innocent:

[puddytat]

It'll be because you'll have one arm shorter than the other:yes:
Or one longer...:blink:

[centaurus]

After checking many, many possibilities, three remain:

1. Frame not straight - I really hope it's not this one 'cause I don't have the money to check and fix it. Also, this bike is my daily commuter so I can't afford to keep if off the road for days or weeks

2. Bent forks - will be checking them shortly miself.

3. Uneven oil level in the forks - does anyone know if I can check this without completely disassembling the forks (like the manual says)?

4. Fucked/damaged damping valve(s) in one of the forks - have no ideea if this is possible and how to check for it (without full fork disassembly).

Anybody know how / if I can do points 3 and 4 without disassembling the forks? I can easily remove the top fork cap but anything after that (spring removal, etc...) involves tools that I don't have so will have to be done at the shop which means money that I don't have - just bought a new set of tires for the bitch.

[F5 Dave]

I'd ignore 3 & 4. I can't see it puling to one side or another as a result. That front end is pretty well tied together.

You could also try putting a spirit level on one wheel or disc till the bike is upright, then on the other wheel to see that it is in the same plane.

[centaurus]

Took the forks off today and did a basic check on them.

The only thing I found was the rods (the thinner half of the fork) seem to be slightly bent to one side - both forks in the same direction. However, I don't know if this bent is big enough to make a difference: with a straight rod secured to the thicker half of the fork and running in parallel to the rest of the fork, the distance between the rod and the fork at the end of the suspension travel part (where the wheel axle mounting unit is "glued" to the fork) variates about 2 mm.

Would this be enough to create my problems?

[thepom]

Bet you its a bent fork,had the same problem with mine pulling to the left and it looked ok till I stripped it and found a kink in the fork.Checked everything same as you did......:sick:

[Kwaka14]

After checking many, many possibilities, three remain:

1. Frame not straight - I really hope it's not this one 'cause I don't have the money to check and fix it. Also, this bike is my daily commuter so I can't afford to keep if off the road for days or weeks

2. Bent forks - will be checking them shortly miself.

3. Uneven oil level in the forks - does anyone know if I can check this without completely disassembling the forks (like the manual says)?

4. Fucked/damaged damping valve(s) in one of the forks - have no ideea if this is possible and how to check for it (without full fork disassembly).

Anybody know how / if I can do points 3 and 4 without disassembling the forks? I can easily remove the top fork cap but anything after that (spring removal, etc...) involves tools that I don't have so will have to be done at the shop which means money that I don't have - just bought a new set of tires for the bitch.

Don't rule out rear swing arm being slightly bent either and also dont just check the alignment front to rear also as verticle alignment also has a bearing on direction, if your tyre (fromt or rear) is at an angle to the road surface it will try to climb.

[CHOPPA]

Man i went down this road with my race bike! My problem was everything we looked at was bent so I couldnt tell you which piece actually fixed the problem haha

We had a bent frame, bent forks, bent wheels and triple clamps haha Im pretty sure the last thing we replaced was the forks and that fixed the problem

[HenryDorsetCase]

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!

what he said.

not sure who that is in Wellington.

my neighbour has a CBR1000RR that be bought as a damaged writeoff. first thing on getting it back on the road was to get it laser aligned. I think it cost him 400 plus GST? something like that. they do it with (Dr Evil voice on) "lasers" or something. (Dr Evil voice off)

[thepom]

Definately your forks,now you have to strip the forks and do a runout check.....roll the shiny silver bits on a flat surface to see how much it wobbles....2 mm is a lot of differance...

[shafty]

Had a similiar problem but found it was only while riding past bottlestores and bars, worth a check

[centaurus]

After removing the forks and installing them back, things are better. I also found a plastic label on one of the forks that was caught in the lower triple clamp. It is possible that was changing the alignment too.

Now, at high speeds it's almost unnoticeable. If I take my hands off the bars it will still go one side, but while normal riding, the pull is so small, it doesn't feel more difficult taking left hand corners.

The bend in the forks that I have seen must be from the factory. Neither the frame or the forks have any scratches to point to a crash and the bike's history is clean (was first registered in NZ).

For the moment it's good enough for me. Instead of spending thousands of $$ trying to get it perfectly straight, as long as the problem is small enough, I prefer spending the money on petrol and tyres.