01 Suzuki Bandit 600s Front end vibration

[Suzuki bandit]

I'm hoping for some help ive been chasing a handle bar shake that comes on at 45 and goes away at around 65 MPH for 2 years now. Its been 2 different sets of tires (Conti Contact and conti Motions) Mounted at different places last set at tricky mikes. Ive changed the fork oil this year and no change although im not convinced its right different amounts from each leg came out 455ml from right and 435ml from left. I refilled the same amount i took out and didnt change anything acording to my book its should have 510ml in each leg so i added some to make it 510ml and the shake is still there. Also the height from the top of the fork down to the oil isnt right my book says 4.4 to 4.6 inches down from the top of the fork to the oil im more like 6 down i dont know if this is causing a issue or not ? I also tried tightening my steering head bearings same result. The chain and sprockets were new last year and the chain has just over an inch slack which is within spec.

Also its alot more noticable when i take my hands off the bars. with my hands off the bars it will shake pretty bad as to where i will have to grab them again but its still there when im holding them as well just not as bad

Im not sure what else to look for to cure this vibration any ideas ?

Thanks in advance Joe

[TheIglu]

Check for warped rotors or wheel.

[Degsy]

steering head bearings

[Rossco]

steering head bearings

How many miles are on it?

[gamorg02]

steering head bearings

+1. vmax's have major issues in this regard too, with bearings or even the adjustment being off.

[Degsy]

Did you measure fork oil height with the springs in or out? It matters. Anyway, fork oil isnt causing your issue.

[Suzuki bandit]

It has 10720 on it now. hard to tell when it started. When i got it with 6800 on it the tires just about junk same with the chain but i rode it the first year and dont remember it happening that summer. Then over that winter i put new tires(conti Contact) Chain,Sprockets. Rode all last summer with the shake. Then this winter i put another set of tires (conti Motions) also changed the fork oil ( I did Measure With the Springs Out ) i Tightened the head bearings this year as well. I dont feel any play in them But i figured it was worth a try anyway. I also Checked the tension using a spring gauge on both fork legs Spec is between 200-500 Grams to move the fork. Im at the higher end at about 450 but its still within spec.

Thanks for the replys

[gamorg02]

for the vmax what cures a lot of guys problems is to tighten the adjustment until the forks don't 'bounce' when pushed over from sitting straight forward (obviously with the front wheel off the ground). just a thought.

otherwise, maybe a damper?

[Degsy]

Wirelessly posted

That's how you adjust them. No bounce when they hit the stops.

[Suzuki bandit]

what do you mean bounce ? If i lift the front end up put the forks straight then tap one side of the bars and the fall to that side ?

[Degsy]

suspend front end in the air with nothing interfering with fork travel side to side (cables, wiring etc). Hold forks straight ahead and let go. Forks will fall to one side and hit steering stop. They should not bounce off the stop. If they do, they are too loose (the bearings)

[Suzuki bandit]

ok ill try it when i get out of work Thanks

[Suzuki bandit]

The forks don't bounce. So I guess back to checking the front rim out

[Degsy]

Wirelessly posted

Also rotors and a sticking brake piston.

[gamorg02]

Wirelessly posted

That's how you adjust them. No bounce when they hit the stops.

i agree but if you use the vmax shop manual technique there a lot looser. when i did mine this offseason i set 'em to the factory spec and it was wayy too loose. they say crank down to 35 ft lbs to seat everything then loosen completely and tighten to 26 INCH lbs. not much at all.

as far as the OP issue, i know some guys have had better luck with certain tires especially ones with smaller rubber rotating mass. say instead of the 120 front do a 110 or what have you.

[Suzuki bandit]

I did pads as well this year pushed the calipers in by hand so I ruled out seized up .I was thinking tire issue that's why I did another set but maybe it doesn't like manufacture's ?

[TheIglu]

The rotors may be warped. I'd check that first.

[Suzuki bandit]

Maybe I'm not thinking about it correctly but if the rotors were warped wouldn't it shake during braking too ? I have nice smooth braking no shaking what so ever

[TheIglu]

You never know.

[stoinkythepig]

Might be the rear wheel bearings, swing arm bearing or rear wheel alignment. That said, I agree with steering head bearings since you know it's not tires. It's possible that one of the bearing races is not fully seated on one side (the race is cocked a little in the steering head) Tightening the bearing won't help in that situation. I fit were my bike; and the wheel, bearings, swing arm bearings, and wheel alignmnet check out OK, I'd order new steering head bearings and ensure they are installed correctly. They are cheap and easy to do. Perfect time of year too...

[Suzuki bandit]

Ok as far as the rear bearings I don't feel any play with the tire in the air moving side to side so can I assume the rear wheel and swing arm bearings are tight ? Rear tire Alignment I used the swing arm marks. Steering head bearings don't sound like a bad idea at this point