Weird Issue on Dommie (power)
 

Hi Guys -

Since I sold my XR650L I've been running an '89 Dommie. It doesn't smoke, doesn't use oil (a thimble full every coupla thousand miles) and it has had a reasonably recent engine rebuild by Lambeth.

It has always seemed a little slow compared to my 650L, pulling to about 80mph @ 5k revs in top, on asphalt. This morning I was riding and it sort of spluttered before picking up again and pulling almost to the redline - 90mph+ (!!!) It was like someone had given me 15bhp extra all of a sudden. When I had to slow again, it went back to normal. The same thing happened a couple of times, but only ever in top. It's hard to describe but it almost felt like I had a semi-auto 5th gear, which changed!

This has never happened before, in about 9k miles of riding. The bike has a clean K&N, a Lazer exhaust and stock headers. I don't know what the jetting is like, but the silencer is the road legal version. I get about 60mpg (?? kpl) out of the bike and the plug is normal colour.

Is it possible that I have an on/off jet blockage? I need to know because I don't want the bike to lean out at wide-throttle, or it will overheat and drop a valve seat. The other thing I was thinking is a possible poor connection at the coil or a timing issue? The bike runs sweetly when it's warm- it will easily tick over at 800rpm.

Thanks a lot...

Hi sounds like running weak worth checking the black carb to head connector as these have a habit of cracking underneath. Your bike should easily pull 100 mph in top. I reckon that the carb main jet should be at least two sizes bigger than standard jet for the filter and exhaust. Regards Andy