Power User
Got the holeshot
I have this cylinder that i purchased about 4 years ago and had it on one of my bikes untill recently, i never noticed till now but it has 2 extra ports in the top section, what are these intended for? The bike always seemed to have no low end grunt but screamed up top a lot more than my other cylinders. Theres also a picture of a stock cylinder for reference.
Got The Holeshot
Arm chair racerJust too addicted
yeah i have those to. except mine are on the bottom the guy i baught mine from said it was ported what are they for....
ATC500AF
The sun shines on a dogs ass every now and then
Got the holeshot
somebody drilled those for extra air to travel through there.are they directionally drilled up?like towards the top of the jug?
Full Walsh CRF 450 hybrid 250r
Power User
Roostin Away
Yup those are extra boost port holes. They let more air & fuel travel over the piston Into the pipe to make your pipe work better than before. The pipe actually pulls air through the cylinder because of a pressure drop from the shape of the pipe.
83 ATC 60-R Cr60 converted with Zinger parts.
83 ATC 70.
83 Tri zinger
ATC 85-R Cr85 engine on shortened 86-R frame.
ATC450AF
86 310-R Drag racer
440 snowmobile powered custom built.
87 Cr 500 Converted to Drag racer
Power User
Got the holeshot
Yes they are pointed up. So is this made for more top or is it supposed to be for all around performance??
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