Hey whats up. I just got a Blaster this winter and I just started riding it. Its a 98 a Blaster and i thought it was supposed to be oil injected and that u didn't have to premix the gas and oil. It turned out that the oil injector tank was taken out and that u did have to premix the gas. so what happened was that i put the oil in the in the transmission that i was supposed to use for the premixing with gas, and I ran strait gas thorugh it. So what happened one day while i was riding was that it started overheating and it doesnt start anymore. So i took it apart with one of my friends and i found that the piston and cylinder are all mest up. What i did was take to my yamaha dealer and they are going to bore it out for me and im going to get a new piston, rings, and gaskets. What i want to know is will there be anything wrong with the transmission since i put the oil that u were supposed to premix with the gas? And how would i go about replacing the piston? I dont have enough money to get it done my the dealer so i have to do it myslef. thank you.

 

If it was only for a short period of time, I do not think you damaged the transmission. Does it shift through al the gears still? You are going to need to drain the remaining premix out of the engine and replace with fresh. Run it for a few minutes and change it again. Just to be sure.

The top end job on the blaster is super simple....your new piston should come with a wrist pin and new rings. The piston will be matched to the bore that the dealer is doing for you. If it is a wiseco kit....it comes with a simple explaination of the install. It would help if you had a shop manual to show you the steps. Whatever you do...do not drop the circlip for the wrist pin into the engine.

If you really need a step by step....let me know. I should be able to type something up pretty quick.

 

I apperciate it for getting back to me. If its not to much trouble i would like u to type me up step by step directions because its my first time taking out a piston and i dont have the money to mess this up. The dealer told me the transmission should be fine because no shavings came out when i drained it.

 

start by taking all of the front plastics off. turn the petcock off then remove the gas tank. remove the expansion chamber. loosen the clamps that hold the carb in place. remove the reed valve. take the head off the cylinder. loosen up the nuts that hold the cylinder to the crankcase. slide the cylinder off the piston. don't let any metal shavings fall into the crankcase. there are two circlips that hold the piston on the wristpin. take one out so you can slide off the piston. take the old wristpin and bearing out and install the new hardware. before doing that though, install the new rings on the piston. install everything the way it came off. try not to scuff up the piston to much when trying to get the circlips in. slide the cylinder over the new piston and keep the notch on the piston ring groove between the opening in the rings. After you get it on, lube the cylinder with some two stroke oil and re-install everything. Don't forget to replace all the gaskets.

 

what would happen if i got a little bit of shavings in the crank case. Is that bad and would it damage the crank case. also should i sand off that built up carbon where the spark plug goes into. thanks again. Also how will i get the compression back in to the cylinder or well that build up by its self.

 

Buy a clymer manual.

You want the cyl bored to the new piston, using the proper clearances. You will also want the ring end gap at the proper clearances. Putting everything together right the first time, using proper clearances and torque specs will save you from having to do it again in the near future.

 

I got the cylinder, piston, rings, and gaskets. When i put it togethor do i put everything the exact same way i took it out or do i have to take any additional steps. If so please tell me.

 

I just got my piston in today and my blaster is running perfectly fine. Thanks for everyones help. It wasnt as hard as i thought i just looked it up online.

 

congrats, [img]i/expressions/face-icon-small-smile.gif[/img]

during your brake in be sure to retorque the nuts on the top end.

 

ok thanks!!