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Posted

I got smoked by a 4mm cub repeatedly last weekend, he said it was done by some shop in michigan. I have a stock cylinder 4mm stroker with 68mm big bore pistons on race gas. the guy said he run pump gas, he had some big ass carbs and cpi pipes, it was very fast. He beat everyone he raced. he had +6 or +8 swinger and still had wheels off the ground at about 100- 150 ft mark.

Posted

They opened the strip up Saturday, I'll have a timeslip on mine come this time next week. I'm running the strock stroke 68mm bore.

My clutch needs some adjustment I think. Cant quite put my finger on the problem. They are definately a top end cylinder though. Noticable difference from my stock cleanup ported 68mm.

 

By 4th I had reeled in an auto trannyd vforce 700 with dual exhausts. He's always gottn me on the rolling starts because of the auto.

Ready to pass him on the more open trails still though.

Posted

here is the response i got from dan last week on the setup.

 

We just got off the dyno yesterday and with Shearer In-frame pipes, 35 PWK, V-Force and our domes on pump gas, motor made 90.53HP and 48.34 TQ on pump gas. The power curve was very broad and very rideable- these cylinders are the real deal! +4mm stroke 68mm bore Cub, 421cc. Not much work at all in the cylinders. Basically cleaned-up porting. Shearer in-frames, 35mm PWKs, V-Force, 155# of compression on pump, timing at 4 degrees. We expect the stock stroke stuff to make 83-85HP.

Posted
here is the response i got from dan last week on the setup.

 

We just got off the dyno yesterday and with Shearer In-frame pipes, 35 PWK, V-Force and our domes on pump gas, motor made 90.53HP and 48.34 TQ on pump gas. The power curve was very broad and very rideable- these cylinders are the real deal! +4mm stroke 68mm bore Cub, 421cc. Not much work at all in the cylinders. Basically cleaned-up porting. Shearer in-frames, 35mm PWKs, V-Force, 155# of compression on pump, timing at 4 degrees. We expect the stock stroke stuff to make 83-85HP.

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i can believe the HP numbers but as for being rideable i dont believe that. hell i have ridden a bike with cub cylinders. there isnt much in the way of bottom end and power comes on around 6000 or so rpms. i guess you could prolly dune ride them but you arent gonna be takin them in the trails without a lot of clutch action.

Posted
i guess you could prolly dune ride them but you arent gonna be takin them in the trails without a lot of clutch action.

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Im guessing that is what he meant by rideable, the low end couldnt me much worse than my 350 had.

Posted
Im guessing that is what he meant by rideable, the low end couldnt me much worse than my 350 had.

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lemme tell u, the low end is practically non existent. they are for dragging and thats pretty much it. they flat out haul from mid to top tho... :bolt:

Posted
thats no shit. they are flat out top end for sure.

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Flat out topend? Got any dyno plots to prove this?

Posted

my 421 cheetah has a ton of low end, way more than a yfz, I can make a video to prove it. there is no replacement for displacement. tell me what you would like me to do in the video to demonstrate low end.

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