Hey guys, I was out on my gixxer this afternoon just cruising around in my community. All of a sudden I thought I hit a rock, I tried to look back but my helmet was kinda not letting that happen I went home and dropped off the lid and went around a bit more, it happened again. But it definately wasn't a rock as I first suspected. I was just cruising around at low speeds like ~25 and slower just trying to figure out wtf was going on.

It seems like when the RPMs are kinda low in 1-2-3 (didn't get the chance to try any other gears) that I get a really bad couple of knocking sounds, you can actually feel it on the bike. Its very strange and goes away in the higher RPMs and is not constant @ a certain RPM.

I went home and put the bike up on stands and pulled off the cover that goes over the front sprocket. Nothing was jammed or hitting the chain. I went ahead and started it up and it idles just fine, no noises, revs fine, etc. I put it in first, eased off the clutch and let back wheel start rolling, it made the noise and a few seconds later did it again. I pulled the clutch back in and it the noises didn't occur, let it back out and it made the noise again. Then I proceeded to go through the gears and it did it at the bottom of 1-2-3.

This leads me to believe that its something drivetrain related. I drained the oil (which was at the proper level of course) and it was perfect, not a hint of bearing material, etc. After that I went ahead and pulled off the clutch assembly cover and shook the whole assembly, it seemed like it could rock back and fourth a bit (maybe 1/16"-1/32"). Is it supposed to have that much play in it? Could bad clutch components cause this? Almost like clutch chatter? The bike is shifting like usual. I know the clutch is worn because I can't get wheel up just wackin it in first and its a 750 I haven't even tried to clutch it up in a long time.


Chain tension is set correctly
Motul 10w40 oil, no overheating, sprockets look fine with no abnormal wear.

What do you guys think? I'm kinda stuck, the bike never really gave me a problem like this before (9k), I just kept up with the general maintenance.
I have a video of the noise and will post it up tommarow
TIA
Later/joe

 

its a suSUCKi, what you do expect. they break easily

 

Thanks for your insightful reply.
I assume you drive a motorcycle that requires no maintenance or repair. That is if you even have one.

 

Has the bike been clutched up a lot for wheelies in the past? That can lead to premature clutch failure.

 

If the clutch was slipping then that would be one thing, if it was a tooth on the primary drive then it would be noisy all the time, same with a bearing in the box. The only clue for me is that the noise is there when you let the clutch out. I would check that the plates are ok and all is tight on the centre. Even better change it for a slipper right now Not sure if they even have a std gen/flywheel but I have had these come loose before and as they sit on the crankshaft the noise is transmitted right through everything.

 

So I take it my best bet is to pull the clutch and take a look at everything? Looks pretty complicated as per the manual. I'll give it a shot though. The guy that had it before me weighed a good 300 lbs and beat on it pretty hard, I knew the clutch was due to be replaced, but I didn't think it would make noises like this
Luke, is that play I'm talking about normal?
I'll probably be pulling it apart tonight and will get back to you guys with the details.
Thanks
Later/joe

 

we need that sound file...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by bigjdog84 &raquo;</TD></TR><TR><TD CLASS="quote">
Luke, is that play I'm talking about normal? </TD></TR></TABLE>

Maybe a spring has gone walkabout, plates just normally spin up rather than clonking. Without feeling the basket I couldn't say if it was normal. I would say that there should be little but on 4 strokes maybe it is normal. I am 99% sure that something will be obvious when you open it up.



Like that

 

If it sounds kind of like you're grinding rocks in the bottom of the bike, that's usually a bad chain. How many miles do you have on your chain and sprockets?

 

http://www.personal.psu.edu/us...e.mov
Please save target as.

Tonight I took out the clutch, All of the gears looked fine, no sheered or rounded teeth. The springs on the pressure plate were all intact. I'm going to be replacing the clutch disks since everyting is out already.

I'm not sure how old the chain or sprockets are. The sprockets don't really look rounded though

 

Anyone? I've got the video hosted in the link above. I'm stumped... nothing obviously wrong w/the clutch assembly out.
Later/joe

 

bump

 

your tranny is jacked.. my old motor had a tranny problem like that in 1st gear.. it would jerk sometimes.. you prolly have a tooth or 2 broken off, or messed up on that gear ring..