kawiking Posted November 23, 2007 Report Share Posted November 23, 2007 im wanting to put a 4-mill in my stock cyln bike. problem is that its been drag ported. not by a big name builder,so... im dont think the guy that ported them knows how to port for a 4 mill. on a nother forum ,i was told i could use a spacer plate instead of having it reported, and that would help. the best is to have reported...yes i know. but nobody wants to work on somebody else's port work. what do you think ??? could i go with a spacer plate or is it just going to be a waste ??? thanks Quote Link to comment Share on other sites More sharing options...
zach45 Posted November 23, 2007 Report Share Posted November 23, 2007 use a spacer plate you be in good shape if not u need to get ported for 4mil crank Quote Link to comment Share on other sites More sharing options...
Screaming Yellow Zonker Posted November 23, 2007 Report Share Posted November 23, 2007 If this guy did the work right than it should just need a touch up on the ports. If he was a "hack" you might want to start over with new cylinders. the spacer plate will work but you might not see the performance that it is capable of. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted November 23, 2007 Report Share Posted November 23, 2007 use a spacer plate you be in good shape if not u need to get ported for 4mil crank You might want to actually have a few more builds and/or ported bikes under your belt before making such statements... It should be ported to match the stroke. Adding a plate will in fact raise the cylinder, but what about the port duration? Smaller ports, longer stroke...still not an optimal mix. Whether or not you use the spacer plate just tells you whether you need to run cut domes/head or not. Your crank is swinging 2mm higher at TDC and 2mm more at BDC....the ports need to be opened accordingly to get the most out of the crank. Now...will it run? Sure...but you won't see a LOT of benefit from just slapping the crank in without getting the portwork to match... Quote Link to comment Share on other sites More sharing options...
Machwon Posted November 23, 2007 Report Share Posted November 23, 2007 dajogejr is right on, get the cylinders re-ported for the 4mm stroker crank. It does depend on the porting already done, but if it has any kind of decent drag port, a spacer plate will create way too much transfer and exhaust duration in my opinion. Converting a set of stock stroke ported cylinders to a 4mm ported set can definitely be done so that it will run good. Quote Link to comment Share on other sites More sharing options...
kawiking Posted November 23, 2007 Author Report Share Posted November 23, 2007 how come cub cyln dont need ported for a 4- mill crank ? Quote Link to comment Share on other sites More sharing options...
bansheefreak Posted November 23, 2007 Report Share Posted November 23, 2007 how come cub cyln dont need ported for a 4- mill crank ? who said this???? when you buy a cub you get a 392 which is stock stroke or you get 421 which i designed for a 4mil crank.. Quote Link to comment Share on other sites More sharing options...
kawiking Posted November 23, 2007 Author Report Share Posted November 23, 2007 AHHH... i was just wondring. didnt know that, that makes more sense...... thank u for clearing that up !! Quote Link to comment Share on other sites More sharing options...
zach45 Posted November 23, 2007 Report Share Posted November 23, 2007 use a spacer plate you be in good shape if not u need to get ported for 4mil crank lol i was retarted last night... i agree with dave.... you can use a spacer plate.... but best perf.... send to fast or someone who can port for the extra stroke.. Quote Link to comment Share on other sites More sharing options...
brian Posted November 29, 2007 Report Share Posted November 29, 2007 Yeah, I'd have a good builder look at the porting at a minimum. Just to be sure of what you have and wether or not it will run the way you want it to. I bought cylinders that were supposedly dune/mild drag ported for a 4mil. "As much as possible without going to a full drag port" is what I was told. A good builder later told me that it was a pretty mild port, and the cylinders would run fine with either a stock or 4mil crank, but wouldn't really get the full potential from either set up. Dont believe much of what other people tell you when youre buying used parts. Get it checked out or just plan on having the work done anyway. Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 29, 2007 Report Share Posted November 29, 2007 im wanting to put a 4-mill in my stock cyln bike. problem is that its been drag ported. not by a big name builder,so... im dont think the guy that ported them knows how to port for a 4 mill. on a nother forum ,i was told i could use a spacer plate instead of having it reported, and that would help. the best is to have reported...yes i know. but nobody wants to work on somebody else's port work. what do you think ??? could i go with a spacer plate or is it just going to be a waste ??? thanks There was a guy selling a set of stock cylinders Drag Ported by K&T for a 4 mill crank. You could probably pick them up for what you would pay to have somebody report the cylinders you have now. I am sure a K&T Drag Ported 4 mill would haul the mail. When I did my 4 mill I found a set of Patriot Racing 4 mill cylinders that needed resleeved. Got them for 100 bucks. Sent them back to Patriot Racing and them Re Sleeved with 66-68mm (400cc-421cc) I got a little under 500 in the cylinders. Sure I could have gotten a cub, but 4 strokes kind of expect to be betten by a cub. They kind of give you once over if you are runnig a stock cylinder. Quote Link to comment Share on other sites More sharing options...
kawiking Posted November 29, 2007 Author Report Share Posted November 29, 2007 thanks for the info !!! i got another ? ive seen like the vito's 4mm crank adds about 10% more hp... is a 4mill that much stronger ?? i'd hate to buy a crank and report and find out it just made alittle more ponnies... Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted November 29, 2007 Report Share Posted November 29, 2007 A 4 mill is deffinatly worth it especially if you get a set of cylinders that are ported for a 4 mill. I would just go with a hot rod crank from jeff at fast. He has the best price. 400-450 I believe. Plus he can put a max load, or tz berring on it for you if you like. Quote Link to comment Share on other sites More sharing options...
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