Hey DBK,

You're in the same boat as me man. I just checked my Blaster because it was making that slapping noise. I am at about 80-90 psi. Through one of my local machinist/mechanic place "Luehring Performance" I get cylinder bored, new weisco piston, rings, wrist pin, clips, and the whole gasket kit for $120. Not a bad price but still don't want to do it often.

I also was running an FMF, K&N, and a 260 main, with the needle in the 4th. If I held it at WOT for more than about 4 seconds in 5th/6th gear it was pushing the envelope. Should have been fatter but I kind a wanted the new piston so I let her go. Also when you get your new piston/cylinder, remember to go way fat to start with. It's better to foul a plug than burn it up

 

Oh! One more thing don't change the pre-mix, just change your jetting. I am running about the same as you so here is a ball-park figure. My suggestion would be to try a main jet in the 280-300 range for the main, that should be safe to start with. If it is still a little on the lean side check your needle and put the clip on the 4th notch down from the top. If it is allready there then keep going up with your main jet size.

 

When I bought it new I had them pipe and jet it at the shop it came from. It always ran alittle rich with the injection. I never really trusted the whole set up, so i switched. I read somewhere that changeing to 32:1 would make it run cooler also. By the looks of the piston, don't believe all you read huh....I no it was my fault and have learned my lesson....thanks for everyones input. At least now i have some guidelines to follow and some "do's and don'ts" to watch out for.....i'm just starting to get this 2 stroke science down.(someday?)....thanx again!

 

Switching to 32:1 will make it run cooler, because it is a fatter mixture, you just need to go up on your main jet some. 2 strokes are touchy to tune right, so don't feel bad!

 

on a side note: have who ever you decide to rebuild it check the side to side tolerance on your rod.. running lean just dont affect the top end :P and if its the top end.. once you get it bored if you decide to.. its not hard to take apart and put back together. just stuff a rag around the rod (them c-clips are nasty lil buggers) and there is a intake/exhaust side to them pistons (notch to exhaust i believe)..

hehe wish four strokes were as easy as two strokes :P

good luck and have fun

 

For pistons that don't have intake windows(or boost ports) cut into the skirt, the "notch" in the piston will always go towards the intake side. Most Blaster pistons have intake windows cut in the them.

Also look for an arrow engraved on the piston crown, this arrow will point toward the exhaust port.

 

sorry for the mistake and my incomplete point.. but when i said "notch" I was talking about the stamp (the arrow).. and some also come with a "notch" on the edge of the piston on the exhaust side