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4 Mil Stroker Build


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So after my trip to the dunes this past weekend I realized how bad I want to stroke my banshee!

 

Ive decided so far to go with a 4mil crank and port my stock cylinder rather than go with a cub ( trying to keep it on a smaller budget)

 

I had a few questions though.

 

Since Im a cheap ass I'm gonna source as many used parts as I can except for crank and pistons. Are Cub heads interchangeable with stock cylinders? I found a couple used cub cool heads but I don't know if they are going to work.

 

So in order to get the clearance the domes need to get "cut" but does this need to be done at a shop or can you buy domes that are ready to go for a 4mil stroker?

 

So correct me if I'm wrong but I think all I need is:

 

4mil crank 115 rods with tz bearings

795 series pistons?

Domes/ Cool head

Port job

Clutch/lock out

pipe reed etc

 

 

What is case port matching?

and what is triple exhaust porting and is it necessary/worth doing

 

 

Thanks fellas!

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I got a 4 mil w a cool head and my domes had to be cut , I'm running stock jugs . I doubt domes come already cut . But that's why god put machine shops on the earth . Gotta stimulate the economy one dome at a time

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You dont need a lock out clutch, only for serious drag racing where your clutch is slipping when you take off. When you think about a stroked crank, for you +4mm, that means the pistons are going 2mm higher and 2mm lower. But Uh-oh! when your pistons go up 2mm more, they'll smash into your domes! Bad news there. If you absolutely want to keep stock jugs, you can report your jugs to be 2mm higher and cut 2mm off of your domes, or you could put a spacer plate in (2mm plate that goes between crankcase and jugs that lifts your jugs/domes by 2mm, stopping piston/dome collision and matching ports). Numerous people dont like the stroker plate though, because it wont give as much performance as cut domes and a report. A long rod stroker has, obviously, longer con rods, most of the time 5mm more (115 rods). Im 90% sure that if you use a stroker plate, you have to have a short (stock) rod stroker, which is what I have. Triple exhaust porting just cuts two more ports on the exhaust side of your cylinders so that exhaust can escape faster. Mostly for racing IMO, and I wouldn't go for it. different pipes are a must for banshee owner, yamaha had some idiots design it or they reeeally wanted to detune the motor. Coolhead is a great thing to have, and IMO pro-design makes the best, but it hurts the wallet a bit. Cub cool heads will NOT work with stock jugs, pretty sure about that. Cub jugs have a different bolt pattern

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 Coolhead is a great thing to have, and IMO pro-design makes the best, but it hurts the wallet a bit.

Cub cool heads will NOT work with stock jugs, pretty sure about that. Cub jugs have a different bolt pattern

Wrong.... the head is the same.

Go with a NOSS or CHARIOT Head,

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Thanks for the correction. Really, I like mine how it is. More mods=more temperamental, so its not too hard to start or breaking down a lot.   I can't give you real specs because 1.)my PO was a real idiot and subbed the stock 14t sprocket for a 12t (STUPID) and had tiny tiny rear tires. and 2.) I have other mods, like different carbs, reeds/ reed cages, different pipes, etc.

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so when they port for say a dune port or a drag port is that the same porting as matching port timing when stroking the motor? or is that an entirely different port job.

 

I understand the concept of porting and what it does I'm just not familiar with it being done on a banshee.

 

But thanks for the good info!

 

And I was just looking at RDZ and they had a used NOSS super cub head for sale which is why I asked about that 

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call Jeff at FAST Racing he will set you up with porting and all the parts you need at a great price!!!!!!

 

he built my 4mil dune ported stock cyl motor and it runs great.

This is the best advice given,call and talk to someone who knows how to give you what you want.
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Any of the site sponsors will give you a great build. Personally I use Brandon & Shay at Wildcard Racing. I'm running a stock cylinder 4 mil and it does pretty good.

My last race I was able to take down 3 out of 4 cubs. The last one ate my lunch :)

 

Seriously though call Brandon. He will get it done.

 

Good luck

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i would go with cam at redline racing hands down. what exactly do you wanna do with the bike? i know you said your cheap and dont wanna spend the extra $ but personally i was like that at one point but then i finally came to realize you gotta dish out some good coin to get better performance. not saying you wont like the 4 mil. they are fun good bikes but if i had to do it again i would of jumped right to 10mil.... even for a trail bike. i grew out of my 4 mil quick. your gonna want more down the road im telling you

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You dont need a lock out clutch, only for serious drag racing where your clutch is slipping when you take off.

 

Coolhead is a great thing to have, and IMO pro-design makes the best.

Negative on both accounts.... More like opinions. However you are entitled to your opinion no matter how wrong it may be.
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i would go with cam at redline racing hands down. what exactly do you wanna do with the bike? i know you said your cheap and dont wanna spend the extra $ but personally i was like that at one point but then i finally came to realize you gotta dish out some good coin to get better performance. not saying you wont like the 4 mil. they are fun good bikes but if i had to do it again i would of jumped right to 10mil.... even for a trail bike. i grew out of my 4 mil quick. your gonna want more down the road im telling you

so how much of a jump in hp&tq will a 4mill, porting (aggressive), pipes give over a stock bike...ballpark..lol...double?

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