XR questions

[tristan18au]

i have a 1998 xr250 and was wondering whether the exhaust gaskets can cause performance probs?
also my clunk is still there in the gear box its not the rod cos it would have let go by now if it was. could it be the oil pump it is a fair bit noisey.
thanks for the help:moon:

 

[tristan18au]

also it rattles to ****ter near the exhuast when hot could it be the fact that there are no gaskets?

its an after market pipe (staintune)

 

[tristan18au]

can someone please help me??!!!!:mad:

 

[Pantaz]

Should have gasket

Any exhaust leak will affect engine performance. The microfiche shows gaskets on the exhaust head pipes. I imagine the Staintune pipe is designed to use the OEM gaskets.

Describe the clunking noise. Does it change with engine speed or wheel speed?

Online microfiche
http://www.bikebandit.com

 

[tristan18au]

a deep metle clunking noise
and it does speed up slightly with the engine revving

 

[Ol'89r]

tristan18au. The only time exhaust gaskets could cause a performance problem is if they are the wrong one's and are too small as to restrict the exhaust opening. If your pipe is tight against the head and the knocking noise is not coming from this area, you may have problems inside the engine.

Your engine uses a rotary oil pump and they don't make noise. I would recommend having a shop mechanic listen to your engine noise. If that is not possible, you may want to start taking it apart. Don't run it any more than you have to because the more you run it, the more it will cost to fix it.

Just my $ .02

 

[mgorman]

Two things come to mind on Xr's.

1.) The cam chain stretches with wear and does not ride well on the top cam gear causing a snatch in the chain like the rear chain when you lug the motor. They also become bound and when the chain comes off the small sprocket on the crank, it snaps straight and causes the same racket. Taking the cover off the motor on the oposite side of the flywheel will allow you to inspect the cam chain when you turn the motor over by hand. You won't hear it but you will see it. This is where the chain link is wrapped the tightest.

2.) Worn primary/clutch grear set. Usualy goes away when put in gear and the clutch is in. When these get old, the slack causes a knocking noise when the clutch tries to spin evenly but the crank doesn't because of compression and firing.

A test you can use is to take a wooden dowel rod and place it on differet parts of the motor while it idles. Place the other end against your ear. The noise will transmit thru the wood like a stethascope. Unfortunatley, Hondas have a lot of dead airspace in the motors that act like echo chambers.

 

[tristan18au]

hey
im going to pull my clutch side of my engine down tonight to look for that clunk, which has got worse.
is there anything i should look for?

=1998 XR250

 

[mgorman]

Check also for up and down movement of your crank bearings by moving each end of the crank.

 

[Danman]

Thanks for the tip on the wooden dowel, never realy thought about using that. I have usually used a big long screw driver. Also, you can acutally buy a automotive stethascope at the autoparts store.