scary sound from under bike?

Ok. I'm hoping this isnt going to end up being something major!?!?!

I get this terrible sound from under the bike when engaging 1st gear.
It started as a little bump, but has gotten worse in the last day or so.

Usually when I first begin to move from a stop. The sound starts when 1st gear is actually engaging...right when it grabs at the proper throttle/clutch ratio.
It sounds kind of like a clunking or knocking sound. I think its coming from under the front/bottom motor area. Hard to tell.

If it was the actual clutch asmbly. The noise would be coming from the right side correct?

The noise stops as soon as the revs get up over about 3-4k and I dont hear It when shifting in or out of any other gear that I've heard.

Its a 93 with only 19k...just hopping its not something that the engine will need to be yanked out to fix

Any thoughts/advice would be greatly appreciated.

-Steve

 

OK lets start with some simple things first, based on the information you have given:

1) Check that your chain is in a serviceable condition, ie: adjusted etc;
2) Check that your gear lever is in good condition, ie: is not bent from a fall or crash etc;
3) Service your master clutch cyclinder, ie: flush, fill and bleed - could be dirt or air in line;
4) Check serviceability of the slave clutch cyclinder;
5) Check that the gear rod is not bent (this what the point 4 engages);

Points 2 to 5 can affect proper gear engagement etc. The point above are only based on the limited info you have given.

Some other questions I have are:
1) It started as a bump, how would you describe it now?
2) Has the noise/bump got a rythme or is it iregular?
3) How are the gear change in general?
4) Have you had any gears slip?
5) After 3000 - 4000 rpm, do you feel anything through your foot pegs? (sound could be drowned from the bike sound)

Cheers

 

first thing I thought of was the chain my question does it make it when just idling in neutral? or when you put it in gear from neutral? or when you start letting out the clutch and moving? yes to many variables here to get an idea.

 

I'm actually getting ready to go to the store for some fresh DOT 4 for the clutch.

The color of the fluid has started to turn brown in the last couple of days.
The level in the cylinder will jump up during hard acceleration an then go back to the lower level when cruising?

Figured it needs a flush today, as pointed out in above answer.

Answers to more specific questions:
NEPTUNE-
1) Chain just serviced last weekend (lube and tightened)
2) Lever operates properly
3) I am flushing clutch this afternoon
4) Not sure about checking for slave cly.operability?
5) Guess I'll check the gear rod when flushing system, its behind the Slave cylinder right?

Other Questions-
1) Clunking sound now...loud knock almost like something isnt moving correctly
Sometimes even a slight squeaking sound as I begin to move.

2) VERY regular sound ...a few quick clunks at the exact same timing ever time I begin from a stop. (1st gear)

3) Gears have a slight hesitation upshifting but otherwsie good on dwnshift.

4) No slipage. though sometimes recentlythe bike will not find neutral.
(At a red light) I have to slightly let out the clutch till I hear the gear engage and then I can up/dwn shift to neutral and the green light comes on.

5) I actually did notice a thumping sort of vibration on my left footpeg in particular yesterday afternoon.




RVFR-

Only makes sound when I start to move
(when clutch lever comes out and gears start to grab)
And I guess while I'm moving too because of the vibration I described above to Neptune.

Thanks Guys-
Steve

 

you say the chain was adjusted, but a chain that's too tight will strain different components and could possibly be responsible for your noises....

 

was adjusted per service manual:
while on side stand- chain slack should read 5/8" - 1"

when adjusted last week I measured slack of aprox. 7/8" post adjustment.
It was 1.5"+ per-adjustment
Manual said running for long distances at sustained highway speeds will create slack overtime. (I commute 40+ miles to work on highway)

 

^ Thank you, was just going to say that. Also take note in the sound when pulling in the clutch at a stop, of course you put it in neutral and let it out listening for the change. You know, now that i think about it, I'd put it up on its center stand and put in gear and look and listen, yes you can do this safely, done it many times. that way you can watch and listen off the bike.

 

how many miles on the chain and sprocket set?????

 

Bought the bike 2+ years ago. During inspection chain/sprockets checked out.
Rear sprok still looks good...not sure about front. Chain is just OK.
I was actually looking at doing the 520 convrs. this season.
new Vortex sprck and chain.

Guess this could be the culprit as well?
We'll see after I flush the clutch....going outside now

I'll post up if theres any changes once running with new fluid.
Probably just going to do the chain/sprokets now anyway, since could be a cause.

Thanks-
Steve

 

if the chain is original, it's probably worn since OEM chains last only 20-25,000 miles.

put bike up on centerstand and rotate rear wheel while feeling chain tension.....loose and tight spots usually indicate lots of wear.

 

ok. Clutch flush done....It was sick. Brown Dot 4, not there was goo in the bottom of the clutch resevior....similar to the first time I flushed my brake lines when going to a dual line system in the front.


We'll have to see if it changes anything.

 

Does this noise occur if you start in 2nd gear instead of 1st?

 

i would say the flushing might do it. sounds like the slave cyl. not completely disengaging the clutches and thats where the hesitation upshifting and neutral could occur.

 

HeyMike-

That is something I am not sure about. I'll test it out tomorrow.
I will say the bike seems much smoother and has no sounds or hestitation now that the clutch flush has been done.

Only time will tell.
Chain/Sprocket is still in order though...

 

Brown DOT 4 will do that to you, anyway, you should feel and hear (nothing) a big difference.

Cheers