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4 mil questions


Jebajoie

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Ok guys I'm a little confused. I have a 4mil long rod. Stock stroke. No spacer plate. Stock cylinders with big bore sleeves. And 68mm blaster pistons. Could I drop a 4mil stroked crank in with long rods without changing my set up or anything and it run right? If not why and what all has to be done. Thanks

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no, you can not. the piston will not be in the right position in the cylinder on each stroke. you will need the porting adjusted. also either a spacer or the head cut, possibly both depending on exactly how you are setting it up. you have a stock stroke now with 115mm rods. basicly same results as if adding a stroker crank with 110 rods to an all stock engine.

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If you are running 115 rods in a stock cylinder/head, thats why you have the blaster piston. The wrist pin is moved up on the blaster piston vs the stock banshee piston. In the end you still have same TDC as stock banshee. If you go with a +4mil long rod crank, you have to port your cylinders accordingly and shave head or use cool head with domes cut for a 4mil. confused yet?

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i dont understand yoru question  if i read your Q right  you say you have a 4 mill long rod init and want to know how to get a 4 mill long rod in your motor??

 

i'm going to GUESS that you have a long rod ( 115mm) stock stroke crankshaft ( 350cc)  and a big bore 68mm stock cylinder motor..  

to do a 4 mill stroker you would need to have the porting check'd by someone that knows how to do this  and then have the domes set up for the stroke.  a spacer plate makes the transfers all crazy and the motor will be a top end only engine if that.  correct domes are the best way to go  and the only way i build them.

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Im building a 4 mil as well stock cylinder cool head 21cc domes race porting +4 timing vf4 reeds with a spacer fmf fatty an exhaust.. i plan on changing pipes to toomey or CPI wat carbs would i get

Keep the FMF and carbs for now, pay to get it ported and domes set up. Believe me, I did it the same way you are. Huge mistake. Wasted money. Bigger carbs will make it worse on a stock port

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