My son has participated in previous discussions on this BB so I thought I'd ask for some advice. He recently took out the baffles from the stock exhaust. At first , the DS ran fine, although very loud! Then it began to run poorly especially missing at high RPM range. A car mechanic friend of mine took a look at the machine and decided to put back the original baffles, padding ect. He then took the carb. apart and cleaned it, although to him, everything looked OK. The bike ran great for about a half hour, then started the same old missing-barely enough power to make it up a small hill. This time we drained the gas tank and cleaned the carb again. I'm hopeful that this will take care of the problem. However, my real concern after watching him start the bike and take it for a brief ride, is the amount of blue smoke coming from the exhaust. My friend said that it is definately burning oil and I confirmed with my son that he has been adding oil on a frequent basis. We bought the machine used from a dealer and I'm now sick about thinking what abuse the prior owner did to this bike. My question is does this sound like a rebuild is needed? If so what is the least expensive way to go and do you have any recomendations? I'm not looking to make this bike into a monster machine-stock performance is fine-especially since I'm paying for it. Can you just resleeve these cylinders? What other possibilities could the blue smoke be from?

Any help/comments/suggestions would be much appreciated!!!

 

Yikes. Oil burning is never a good thing. It is possible that the valve seals are letting excess oil by, or of course, the rings. I don't believe you would want to resleeve the cylinder because as I understand it, it has a nikaseal coating. In fact the shop manual says that if the cylinder is out of spec to replace it.

Your mechanic friend could possibly help you with some tests to determine the cause of the oil consumption. Such as a dry compression test, a wet compression test, and a leak down test. You may be able to, if necessary, just re-ring it. But don't hone the cylinder. If it is the valve seals/guides, you can have a good automotive machine shop perform the work needed. The head is very basic and easy for a machine shop to service.

Good Luck.

 

You can do a light ball hone on the cylinder if you like, it won't hurt the nikasil. You can also bore the cylinder out if you like it just hast to be re-nikasiled. This cost about $150.00 at a place like PSI performance. You should do the leak down testing though it will help to find the problem.

 

Your carb problem sounds like a kinked fuel vent hose not letting air into the tank to replace the fuel used. This will stop the fuel from flowing into the carb after it runs for a bit.
To test, loosen the gas cap when it starts to act up and see if it runs better. The vent hose is about 5 feet long and winds around the fuel tank a few times. There are plenty of places it can get kinked if it wasn't routed properly. There are a couple of different suppliers of vented gas caps that you can use to replace the stocker if its the problem
Blue smoke is never a good thing, first thing that comes to mind are the rings. As previously mentioned, a leak down test will tell you if there is a problem. The Rotax engine has proven to be a very durable engine and many on this site have proven it time and time again. I find it hard to believe you have a problem with your rings unless the previous owner ran it without an air filter in place. Check the crankcase vent lines that vent into the top of the air box for kinks or restrictions. A restriction in the crankcase vent hose will also cause excessive oil consumption but its easly fixed. Good luck

 

Guys:

THANKS FOR YOUR RESPONSES! Your suggestions make sense on first finding out where the leak is at before proceeding ahead.

take care,

Bud

 

If you took the packing and baffles out of the stock exhaust, you would need to re-jet. Maybe that is casuing you miss fire and poor running.

02BAJA

 

i cut the spark arrestor and restrictor tubes off the endcap and i didn't rejet and my ds runs fine

 

Probalby runs like a bat outta hell. Its running lean. Lean makes power!! Its fun till you need a rebuild.