first build wanna do it right but dont have deep pockets

I have seen quite a few crappy bore jobs posted on here from their local machinists. i have even gotten one myself from a guy that really seemed like he knew what he was doing and he charged like 100 instead of 60. ken works on blasters all the time and does great work. weisco prolite pistons are the best around. that is really the only piston that anyone backs up here.

ia this not a good piston CAST BIG BORE PISTON WITH...
 
cast pistons are not as strong as forged pistons. The forging process aligns molecules in the metal allowing it to withstand "scrubbing" better than a cast piston. When a cast piston comes apart it crumbles because each molecule was poured into the mold and settled down in there with its neighbors. Forged pistons are heated aluminum slugs and then slammed into shape by a huge heated high speed press which makes them stronger.


Go for the wiseco, you'll be glad you did.
 
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Holy crap, who got to that thing? Also, paint stripper will remove the paint but not harm the plasstic. Probably too late for that piece of information to be useful now, but for anything else you want to strip...
 
to back sicivicdude up. I have burnt up cast and forged pistons. the forged piston just scores and seizes but the cast piston disentegrates and all the little pieces end up melted all inside your cylinder and crank.
 
Holy crap, who got to that thing? Also, paint stripper will remove the paint but not harm the plasstic. Probably too late for that piece of information to be useful now, but for anything else you want to strip...

yeah i know i used it on the first layer but this stuff was like concrete and i also needed to get off a layer of plasatic that had become dry rotted.
 
You don't have a choice but to use sandpaper on the plastic to remove the top layer but all of the pain will come off with paint stripper like strip-ez or similar.
 
My son bought a Blaster with a hole in the bottom of the case. The piston skirt had broken off and was punched through the bottom of the case, making a 1" hole. He owns a DT200 as well, that we were checking out due to low compression, turns out its skirt was cracked and almost broken off as well! The window design of these pistons weakens the piston so buy the best you can and replace them sooner rather than too late.

I use cast eutechtic pistons by ProX, Vertex, KTM and Namura in my KTM. In fact Wiseco is the only manufacturer of forged pistons for them I know of. I have never had a broken KTM piston but have seen several cracks. Due to different design, the KTM pistons are less likely to fail catastrophically. I have had problems with forged pistons from time to time. They expand more and at a different rate than the cast cylinder around them, so they need more clearance and need careful warming up. Applying full power too soon on forged pistons will seize the engine. The extra silicon in the cast eutechtic pistons acts as a lubricant for less friction and the ability to use less oil in your mix. My KTM can run on 100:1 in a pinch (indoor use or by accident, emergency get home) but that will score a forged piston.

My son's YZ125 piston was very similar to the Blaster piston. We quickly learned that pistons were a wear item and needed yearly replacement if we didn't want to do a crank and bore job. High quality cast pistons worked OK if replaced often, forged worked well and longer, but only if you respected their slow warm up needs. Cheap pistons from no-name manufacturers are not worth the money. Avoid them.
 
alright sorry its taken me so long to get anything done but these 60 hour weeks make it hard to get anything done, i have the plastics almost finished and hopefully will have the frame stripped tomorrow so i will post some more pictures, and i got the tusk tool finally so i have the clutch off and will post when things progress.
 
A flywheel puller is about $20. Spring a bit more for one of the 4 sided pullers (different thread on each arm) and it will pull 90% of all small engine flywheels off. I have one and it does pull the Blaster flywheel. Be careful of left hand threads on flywheels and on clutch side holding nuts. I cannot remember if the Blaster has these, so be aware that some engines do.

The cases have to be pulled apart too. I used a regular 2 sided puller with extra long bolts threaded into the case up to the arms. Could not get long enough bolts when I needed them so just welded a couple together. It is a long reach from the case to the end of the crank. Things come apart easy, so no forcing stuff.