What could this be?

[Butter Bean]

Ok time for another round of "Guess whats broke"

BIKE: '08 Busa / 1,572 miles / BMC air filter / TRE / Micron Slip on / speedo healer / ss break lines / a few wheelies never slammed down hard & none more that a few hundred feet / never raced / 1000 mile service preformed by dealer / synthetic oil & engine ice / tightened chain before ride

Problem: on a 250 mile ride yester day i noticed a rattle sound noise which sounded like it was coming from under tank. this sound continued to worsen through out the day. not very loud but enough to know something aint right..

i did a few roadside inspections to see if anything was loose. nothing..

i noticed that the rattle was in tune with the engine rpm and not the roadway / suspension travel.

i throttled up on the sidestand to see if it was in the enging but it does not happen while in neutral.

the rattle only happens while the bike is in gear at about 2500 to 3500 rpms. accelerating from a stop or whatever. i do not notice it at highway speeds but this could be due to windnoise.

i also noticed that the shifting was not as smooth as normal and i also noticed more vibration in the hand grips through the whole rev range.

also noticed that the bike would hang up while downshifting and once it got stuck in third gear at a redlight. had to rock bike and let out clutch to get it to shift down to second.

power feels normal
clutch feels normal

it's under warranty and i will be bringing it to the dealer this week, but i would like to go in informed. anyone got any ideas what it might be?

 

[Rapstar]

How tight did you adjust the chain? check it again?

 

[Butter Bean]

Im pretty sure that i had it right but i'll double check. good idea thanks.

 

[Got-Busa?]

Check your clutch basket bolts. Some people reported them backing out so I'd give that a look before taking anything else apart...

 

[racerV]

Check your clutch basket bolts. Some people reported them backing out so I'd give that a look before taking anything else apart...

That's what I was thinking!

 

[Butter Bean]

How tight did you adjust the chain? check it again?

I think we have a winner..

i went out to check the chain because i didn't have the time or knowledge to start looking for the clutch basket bolts. I noticed that the chain was considerably looser than when i tightned it before the ride. I took it for a short ride and everything was fine.. no rattle.. shifting fine..

i went home and refered to the manuel and took out the tape measure to be sure. the slack in the chain was proper but like i said it was much looser than when i tightned it. guess i stretched it a bit.

I also forgot to mention that on the ride i had my wife with me. which maked me wonder. when you tighten your chain do you do it with your weight on the bike? also would a 100 lb passenger make it too tight if she is not on the bike when the chain is tightened?

thanks for all the input guys. you saved me a headache.

 

[ToXSicK RoCKeT]

That's what I was thinking!

BINGO! Thats what I'd say also....

 

[twotonevert]

A passenger will make the chain tighter than with just you on it. You should adjust your chain with a helper and be mounted on the bike. If you want exact tension with a rider.

 

[dadofthree]

Was going to suggest chain tension, hope that's it.

 

[djsin]

Check your clutch basket bolts. Some people reported them backing out so I'd give that a look before taking anything else apart...

do this Immediately!

 

[djsin]

everyone else will chime in but I like to have about 1 1/8 inch of play when i ride by myself and 1 1/4 inch of play with the wife...she is 6 foot tall and 175#s though

 

[Steve@OrientExpress]

Generally speaking the factory recommended chain slack is for an unweighted bike on level ground with the sidestand down. This provides enough slack for any movement of the rear wheel, or the extra weight of the rider and or passenger. Always best to be a touch loose than a touch tight if there is any doubt. Adjusting the chain for recommended slack with one or two people on board will most likely mean a very loose chain...

 

[SpeedAdict]

As long as we are on the subject of chain maintenace, I hope that you are lubricating your chain at proper intervals as well. Just wanted to put this one in there to stir the pot.

 

[mike1180]

Generally speaking the factory recommended chain slack is for an unweighted bike on level ground with the sidestand down. This provides enough slack for any movement of the rear wheel, or the extra weight of the rider and or passenger. Always best to be a touch loose than a touch tight if there is any doubt. Adjusting the chain for recommended slack with one or two people on board will most likely mean a very loose chain...

I agree.
Do it like the manual says, no rider.

 

[EarlyBird]

I set my chain slack near the end of the recommended adjustment. .75" is the least amount of slack to 1.25 being the loosest. I run 1.25" (Moving the chain up and down in that range of measurement) of slack with no rider on it. Just double check it after you torque everything and after a ride. To tight binds the rear suspension and too loose...the chain slaps the swing arm and could jump off the rear sprocket!