Porting For A 4mm Stroker?

[robertg]

I just bought Superjet a 4mm stroker crank off eBay. What cylinder options do I have? I have a 61X and 62T cylinder. I know I have to get new domes machined but is it necessary to get the cylinder ported. I am looking for bottom end power. From what I read Art at Jetworks is the guy to call for this.

The crank is a new modified stock crank but It is was lot cheaper than a billet crank.

http://cm.ebay.com/cm/ck/1065-29392...&lk=ItemDescriptionANDimage&Item=270050868292

 

[Mile9c1]

You can use uncut domes if you use the head spacer that Riva sells for like $10 in their clearance section.

 

[godocgo]

you should have let me win it. i had a motor waiting for it:smile:

 

[robertg]

you should have let me win it. i had a motor waiting for it:smile:

I didn't win the auction by much at all.

 

[robertg]

You can use uncut domes if you use the head spacer that Riva sells for like $10 in their clearance section.

I will have a look but I need domes anyway,

 

[D-Roc]

what if you use flat top pistons? isn't there a 4mm difference when switching to flat tops that would have to be decked with stock stroke cranks, but with a 4mm crank it would line back up? i always wondered about this and never got a clear answer.

 

[godocgo]

i bid 200 + over the current bid price with less than minute to go. i thought that was enough.

 

[robertg]

what if you use flat top pistons? isn't there a 4mm difference when switching to flat tops that would have to be decked with stock stroke cranks, but with a 4mm crank it would line back up? i always wondered about this and never got a clear answer.

With a 4mm stroker crank the piston will go 2mm higher at TDC and 2mm lower at BDC than with a stock crank. So at TDC the flat top will be 2mm lower and at BDC it will be 6mm lower. You would still have to deck the cylinder 2mm to get the correct squish. The transfer ports would be open a lot longer also.

This port timing stuff is way over my head.

 

[waterfreak]

I think Jetworks have alot of experience with this kind of set up. I would look them up!:biggthumpup:

 

[jetskiking]

yep, call Art at jetworks. He could hook you up with that setup. I know that he builds a 4mil for like two grand when he suplies the crank and head . so if you already have it you could probably get it done cheap.

 

[njfl]

Yesterday, 2nd Nature had his new Jetworks 4mm stroker at Lanier. Did any of you get a chance to try it. From what I hear it hits hard and follows through nicely.