hello i recently traded my 2000 Polaris magnum 4x4 that needed rebuilt for a running blaster after about a tank of gas it blew up so i ordered a stock mm bore from wiseco and a wiseco top end gasket kit put it in the motor and was riding all of a sudden the motor started knocking because the piston was hitting the top of the head i talked with a mechanic and he told me to order a new crank kit or rebuilt the old one so i bought a vitos stroker crank with the same mm stroke my question is can i just put the crank in the engine or is there anything else i need to do before i place it in the engine. also does any one know how much hp i gained ?

 

also how much would it cost to get the stuff does that needs done if anything needs to be done ?

 

I see a couple of things wrong with this picture that I'm confused about. 1st, if the engine blew up, you more than likely needed to go to a bigger bore piston, so if it was the stock bore, you would have needed to go to .020" or bigger to get the scratches out of the cylinder.

2nd, a stroker crank has a longer rod than a standard crank, so if you took out the factory crank, then a "stroker crank rod is not going to be the same length as the factory crank rod. Even if it is longer, that's no problem but sometimes you need a stoker piston to match the stroked crank. I would do some research before you put it all together.

3rd, I could be totally wrong, but I find it hard to believe the crank bearing was so loose that the piston was hitting the head. In my experiences, if the crank bearing is that bad, it will lock up before it gets that loose and the engine wouldn't run.

 

yea i tore the head apart and the intake side of the piston skirt is gone lol and i only had to hone it i took it to a machinist and he said its only off by a thousandth with the crank i ordered a smaller connecting rod with the same stroke so it would work (a mechanic told me i could do that ) and for the center bearing wen i pulled on the connecting rod it was very loose but this is my first 2 stroke lol and i think its easier to work on than my previous 4 stroke lol

 

CRANKSHAFT :: Blaster ::.... Which crank did you buy? Vito's lists 2 on their website - a stock stroke and a +3mm stroker that claims to add 4 HP. They say no machining required for either. You should replace the outer crank bearings and seals while you have it apart and get new gaskets for the lower end.

 

i bought the one that adds 4 hp and wen ahead and got gaskets bearings and seals to make it like a crank kit

 

Then you should be good to go. You have to split the lower engines halves apart to get the crank out. I've never done it on any bike I've ever had before, I always pay my local mechanic $50 to do the bottom end work and I take it from there. It's worth it to me because the transmission can get scary if you don't know what's going on - lots of little parts and pieces!

While you have it apart, I would check the cylinder walls again. If there are any scratches that can catch a fingernail, it needs to be bored. I have blown up my fair share of 2 strokes, and have helped plenty of buddies rebuild their's, and I have never seen one that didn't need boring after blowing up. But, your's could be an exception if the intake skirt broke off, alot of times when they blow, the exhaust side piston gets too hot and melts the rings.

 

yea i took the head to a guy that is well know and that's what he told me cuz im trying to stay within my budget lol i think the skirts where slapping is what mite of caused it it break off but im not exactly sure lol and as for the lower ends im ok or good with them i know more about a lower end more than a 4 stroke top end lol hard to believe but its true lol is there any other performance parts you would recommend here in a couple weeks im gonna order v force 4 reeds cuz a friend has a 350 banshee twin and he told me that they are greatly recommended cuz he runs them and they make a big difference

 

a vito's degree key would add some bottom end torque, and a reed spacer. both are cheap and easy upgrades.

 

ok thanks for the help ill look them up