loud noise!!!

[jstanforth]

so i need some help. whenever i put my bike into gear i hear a loud thumping noise coming from the bottum of the motor. im just throwing this out there but could it be my front sprocket? i have no clue when they were changed last. any help will be great.

[Kreylyn]

so i need some help. whenever i put my bike into gear i hear a loud thumping noise coming from the bottum of the motor. im just throwing this out there but could it be my front sprocket? i have no clue when they were changed last. any help will be great.

Is it a one time thing each time you put it into first gear from neutral at a stop, or everytime you shift even when moving?

Krey

[GytRDunKat]

or everytime you **** even when moving?

Krey

OMG, you forgot the "f" Nice use of the censor

[jstanforth]

Is it a one time thing each time you put it into first gear from neutral at a stop, or everytime you **** even when moving?

Krey

its all the time. i first noticed it when i pulled out of the drive way. but even at a stop and i shift into gear it still does it.

[Kreylyn]

its all the time. i first noticed it when i pulled out of the drive way. but even at a stop and i shift into gear it still does it.

My mispelling, and then the sensor catching that, didn't make that very clear...


Do you hear the noise when you change gears 1st-2nd, then 2nd to 3rd, then 3rd to 4th, so on... or only when neutral to 1st?

When you do hear the noise, is it a single "clunk" at the time of the shift?

Does the bike jump or pull any when you do shift and hear this noise?

Krey

[jstanforth]

My mispelling, and then the sensor catching that, didn't make that very clear...


Do you hear the noise when you change gears 1st-2nd, then 2nd to 3rd, then 3rd to 4th, so on... or only when neutral to 1st?

When you do hear the noise, is it a single "clunk" at the time of the shift?

Does the bike jump or pull any when you do shift and hear this noise?

Krey

its all the time. it does it thru all gears. the bike doesnt really pull or act any different.

[Maslonik]

i dunno if mine is doin the same as yours but when i shift from neutral-1st i get a pretty loud clank, a small jump but not to the rear tire. my idle is a little high (2k) somtimes but when its down around 1.2k it doesnt sound as bad.. all other gears are fine

[Kreylyn]

Some noise is to be expected with these motors when shifting... it's normal. If it's excesively loud, it could be a possible issue (possible, not for sure).

I would check to make sure the chain is adjusted correctly, see if someone else can get beside the bike when you shift at a stand still and get a more precise idea of where it's coming from (internal to the engine or external along the chain/sprocket?).

It may be nothing, but it's not a bad idea to look into it to make sure.

Krey

[jstanforth]

thanks guys for all your help. im still learning with the bike and the mech parts. im good with cars so i think i should be able to get this taken care of now that i have a little help.

[heaton750f]

I am getting the same noise. Its a pretty lound clunk but I am trying to syncronize the gears a little by reving the motor when I **** and it seems to be helping. I just adjusted the chain to about 1" play and it seems like it got a little worse. Dont know. Might have a expert look at it.

[Kreylyn]

I am getting the same noise. Its a pretty lound clunk but I am trying to syncronize the gears a little by reving the motor when I **** and it seems to be helping. I just adjusted the chain to about 1" play and it seems like it got a little worse. Dont know. Might have a expert look at it.

Shifting from neutral to 1st should be done at low rpms... under 1500 at the most. If your bike is set to idle higher than 1300 rpms, you will get a loud "kathunk" sound when you shift into first gear.

The rpms should match your traveling speed for the gear your shifting into at higher gears going down the road. For example, "blip" the throttle when downshifting and slowing down.

Some noise is to be expected. This is never really a quite unheard noise. If it's really loud, or you feel the bike "jump"... then something may be wrong.

One common thing might be the choice in oil. A better oil option can improve the "smoothness" of the shift, and quieten it down a bit over bad/old/contaminated oil if that is what is in it.

Krey

[heaton750f]

Okay. I dont feel the bike jump at all. I am getting used too shifting now and it is smoothing out. Just from 2nd to 1st I got shift it to slow and I can feal neutral. What is the best oil to use in a kat 750 w/ 30,000 miles? It is pretty cold up here. Right now its stays between 30 to 50 degree's on average.

[Patch's]

Have the same bike and I don't down shift into 1st unless my rpm settle low and less than 10 miles per hr.
I find the bike runs smoother with a 50 instead of 10w40 in typical weather!
Likely get more answers to your ??? in the other forum.