Hi,

I've been riding alot of fire roads and trails recently and riding the bike in 5th gear at some speed. When I roll off the throttle there seems to be a knocking or clunking that I can;t place. The bike runs fine but don;t like random noises. Could this be the piston? It's an 04 model and I bought it 6 months ago. I don;t know if Piston/ ring hase been changed- would this be recommended? How easy is the job and cost of parts?

Many thanks for your help.

Mil

Just done the rings on my '04 (after it chewed it up and spat it out!) easy enough too do although a bit costly for what you need!

if the engine pings or knocks on the overun after you have shut off, i would recommend a de-coke, i do my bike twice a year at least. remove the head, barrel and piston, scrape the carbon off with a razor blade and the finish off using a scouring pad and brake cleaner. also remove the rings and clean out the ring grooves. works ever time on my bike. hope this helps.

if it sounds like somebody hitting your cylinder head with a toffee hammer and probably always under the same circumstances then almost certainly one of three cheap things will cure it,

A, use super unleaded

B, put a 32.5 pilot jet in,

C, or take the head off and decoke the top of the piston as described above.

the first will cost you a fiver and take no time, the second 8 quid and remove the carb and replace the jet 1 hour max, to get the head off ( and the rest to actually get at the thing) is going to take a leisurely morning and the price of a head gasket another few quid.

not likely to be your rings..

Edited March 16, 200719 yr by totalshell

Thanks for the replies everyone. I will strip it down and de-coke and hopefully that will sort the issue.

Is it necessary to replace the head gasket when I strip it down? Or will it seal ok with the original back in?

Cheers fot your help

Mil

you can re-use the old head gasket , use a very thin smear of good quality "instant gasket" too much will block the water passages in the gasket. really the best practice is to use a new head gasket, the base gasket if in good condition will always "go again". get the spanners out and good luck!

Has there been an alteration to 04 and later? I had to pivot the motor down to get clearance on my 03 for the barrel to come off - the lug for the top engine mount hit the underside of the "tank". Was tempted to "ease" the tank a bit but I don't think it's feasible with what is the strongest alloy tank in the world. Don't ask about the major operation to get the sumpguard bolted back, I wouldn't want to do that again. Even worse than the old MAR with its fine pitch theads.

I did turn the barrel slightly too gain clearence I admit!

As for getting the sump guards on Most probably the hardest easy looking job going!

On my 04 mont . I used a G Clamp and ratchet strap to Get the Sump Guard back on . it took 5 mins max. Not sure if it is any harder to do a Beta ??

Now you say that I think I used a couple of G-Clamps in the end

Thanks Barry. It's obviously one of these things where tolerances vary between individual bikes. I couldn't get the barrel off the studs to twist it. If I ever have to remove it again I'll try shortening the studs by the visible single thread which might just make the difference.