Hi, I have a problem with my 04 Gs500F. When I give it a bit of gas the rings on the Rotor catch on the Caliper treating me to a jolt and causing the bike to be unridable for safety as it threatens to lock the front up when it happens. Its fine at constant speed or light acceleration, it hits when i give it about 1/3 of the throttle.
The cause of the problem is a stupid lapse in memory by me, I forgot to remove the disk lock before taking off and I assume it bent the rotor or the caliper itself, So I replaced both but that hasn't fixed the problem so i was hoping someone here might have an idea of whats going on.
Sounds nasty! If you've replaced the calliper and rotor, you'd tend to think it must be some misalignment somewhere caused by the 'incident'. - Calliper mount or disc rotor mount maybe. The calliper bot holes, were they undamaged? Slack there could possibly cause this. Strange that it comes on with certain throttle opening though. Does it happen at all if you coast in neutral at speed, or just when you accelerate?
Did you replace the calliper and rotor with new ones or used ones?
It's fine at constant speed, although didn't go above 40km/h for safety. It seems fine at light acceleration but as soon as it hits about 1/3 throttle it starts catching, i'll upload a photo when I get home as you can see where its catching on the rings.
The Caliper bolt holes seemed fine when I replaced the Caliper, same with the rotor mount, both felt solid, I replaced the caliper mount with the caliper itself.
New Rotor, used Caliper.
Thanks for the reply.
I'm wondering if that leg of the fork is twisting under load and forcing the caliper to ride the rotor.
Depending on how hard the hit was when the lock slammed into the caliper I could see it introducing play at the axle.
It could be, i did give it a bit of juice when I took off, what would need to be done to fix that? would just be a case of new bearings and tightening everything up, or a bit more involved.
Also it may be important to mention, I had a trouble getting the axle to line up with the right fork properly when I put the wheel back on after the rotor change, not sure if its just me or if the fork is out of wack.
Quote from: gsnewcastle on November 22, 2016, 08:54:33 PM
Also it may be important to mention, I had a trouble getting the axle to line up with the right fork properly when I put the wheel back on after the rotor change, not sure if its just me or if the fork is out of wack.
I'm willing to bet.
A few things could be the cause or the solution. Bearings, axle, hub, the lower fork leg... Any combination of the same...
Just gotta start somewhere.
I'd get the bike up on the center stand, weighted onto the rear wheel, and see if there's play in the front wheel.
I believe you mentioned a photo? See if you can get a shot looking "down" the rotor so we can see how the pads and caliper are aligned.
yeah I'm gonna take some photos when i get home after work. I should be home in about an hour.
I'll give it a check for play and start with the simple and cheaper stuff first. Hopefully its not gonna cost me too much.
I can't feel any movement in the wheel or fork, I will take the front faring off tomorrow to have a good look at the forks, i would do it now but its pissing down outside and the lighting in the shed is a joke.
some photos
(https://s5.postimg.org/bac34nmcn/20161123_165842.jpg) (https://postimage.org)adult image hosting (https://postimage.org/)
(https://s5.postimg.org/r9uqo7ief/20161123_165852.jpg) (https://postimage.org)image upload no size limit (https://postimage.org/)
(https://s5.postimg.org/llofxbe1v/20161123_165852.jpg) (https://postimg.org/image/llofxbe1v/)
(https://s5.postimg.org/4zbh1zahz/20161123_165919.jpg) (https://postimage.org)adult image hosting (https://postimage.org/)
(https://s5.postimg.org/s5vthehgn/20161123_170407.jpg) (https://postimage.org)image upload no size limit (https://postimage.org/)
(https://s5.postimg.org/6tobjpxif/20161123_170100.jpg) (https://postimg.org/image/tidijaew3/)image upload no limit (https://postimage.org/)
That rotor looks awful. Didn't you say you replaced it?
It's hard to tell much from the pictures. Are the mounting pins being hit? 3rd pic right above where it says 4.5mm
I think yeah he said the rings on the rotor are catching... is that the same as mounting pins?
And I agree, that rotor doesn't look very nice... can't be new... maybe "previously enjoyed, new to me" rotor ?
Good luck gsnewcastle, been watching this thread to see what happens... sorry about all your troubles :technical:
You may have bent the caliper mounts on the fork leg so the caliper is skew.
Other possibility is the caliper bolts are too long and protruding too far past the caliper, catching the disc. On my bike one was longer than the other until I replaced them with Allen bolts.
If something was bent or damaged wouldnt it be catching at slow speeds also? Why is this only happening at speed and without brake application?
Were the mounting faces between the disc carrier and wheel hub clean and undamaged and are all the disc holding bolts fully home and torqued up?
I think the carrier may be separating from the hub as the speed and the consequent forces it sees increases :dunno_black:
It has only happened at slow speeds and only when the front end was lifted by acceleration. If I had to guess I'd say he bent the right fork tube when the disc lock hit the caliper stopping him with a bang. :dunno_black:
Looks to me like a bent fork tube and/or axle. It's as if it is twisting as the suspension lengthens with acceleration. Does it touch when the bike is on the centre stand and the front end unweighted?
The condition of the wheel hub and lower fork leg would also need some close inspection.
It would be wise to get an appraisal from a good bike mechanic.