Well I just got my bike and myself legal this past weekend and have started riding to work. I have noticed in lower gears *1st and second mostly* if I accelerate from a stop normally I can feel a thumping about twice before I shift coming from the rear. If I accelerate hard it is not there but coming to speed semi quick its there in the first two gears. It sometimes will do it if I am in third and give it decent gas to start climbing rpms quickly but not always...I checked the chain condition and it looks to be good although it could use a lube, and I tried to adjust the tension and tightend it a little but it doesnt seem like that changed anything. Any ideas of what to look for?

98 cbr f3
front and rear sproket upgrade *2down 1 up*
no other mods might pertain to this I would think. Any opinions or suggestions would be cool.

Dave

 

oh man, this could be several things. hard to trouble shoot on line.

could be tires, bearing, chain, sprockets.

1st put the bike up on a rear stand, make sure everything is good and tight. axle bolts and stuff, then checkfor play in the bearings of therim and the swingarm. see if the tire or the swingarm will move left to right any, it should have no play at all. all tight as a drum. roll the tire with it in nuetral see if you can see or feel anything.

definalty clean the chain up real good and lube it well.

 

Since its only happening as your taking off, if it was your tyres or bearings, you would get an exagerated feed back as speed increased. So I reckon its your chain, could be rooted, but I thinks its because you have to much slack in it & the sudden tight to loose (lengths of chain) OR you have overtightened the chain, not allowing for the tight spot(s) This is giving you that noise & sensation. You have to adjust your chain at its tightest point, that is, putting the bugger on its center stand, rotating the rear wheel until you find the point in the chain between the front & rear sprockets that tightest (moving the chain up & down). Lube the chain as well.
The only other things that springs to mine ( pun, oh I kill myself) Is your rear Suspension adjustment either being not correct (either worn or set up incorrectly).


[IMG]local://upfiles/9500/96EAF83FD49B41848CC5935B5689276D.jpg[/IMG]

 

^^^Never heard that before, Pace - makes good sense!

Gonna go ahead an second on the problem being the chain. My guess is it's more of a "tick," ratherthan a "thump."

If you feel safe doing so, take the bike around your block (assuming it's not Manhattan) without your helmet. You can hear your chain and all it's noisyness that way. To be honest though, if this is your first bike the whole thing is prolly making more noises than you can shake a stick at, lol.

Don't worry about the trip around the block...

 

i would have to say rear wheel bearing.

 

I had something like this last year andso I replaced the front and rear wheel bearings and have not heard a thing this season. Their not too expensive so I'd just change out the wheel bearings or at least check them to be sure they run smooth.

 

Had a click in mine, thought it was the bearings so I just replaced 'em all, like you said they're not much.

Anyway, got it all done, fired it up, pulled away from the first stop sign and BAM! Click, lol... [:@]

In my case it was the chain (which looked good actually).

 

well after further inspection the chain is in DIRE need of a lubing. I must have originally looked at the only spot on the chain with decent lube, the rest of the chain is pretty dry. I will lube the crap out of it and check the chain tension *ie check for a tight spot* and see what happens. I guess thumping probably isnt the best description. I would more call it a little kick back or tap. *almost feels like someone taps on the bottom side of the peg like twice between the time I start accelerating and when I have to shift.Also a little drag at those times, both of which feel like they are coming from the rear wheel. Almost the same feel you get if you let out the clutch without enough gas taking off...I am really hoping its just an adjustment and lube thing.
Dave

 

^^^Clean it first!!!

 

well I cleaned the chain and lubed it up and guess what, noise is gone. I will have to ride to work tomorrow to be sure but it didnt make any noise and actually ran much quieter *chain drive* and it used to do it almost every time..we will soon see. Thanks for everyones help and opinions. you guys are great.

Dave