Gt5 Stroker

[flybytaco]

ok so i'm building a half power king (top end) on lower end of a skyhawk gt5 turns out the pin of the powerking is 4mm lower than the pin on the gt5 so when the jug is on the piston sticks out 4 mm. so I went to my friends fab shop and machined a 3.2 mm spacer out of aluminum and spaced the jug with 2 gasket 1 on top of spacer 1 on bottom for a combined thickness of 4 mm so I guess I have myself a stroker motor cant wait to run it.. lemme know your thaughts... BTW i'M CALLING IT THE PEEJET LOL srry for yelling

 

[impression]

oh my

very very nice.

please post pics

 

[impression]

curious. which con rod/piston are you using in which combo

edit :

hang on, if i've read this right if i used the rod/piston front the powerking with my skyhawk i can get the same effect ?

 

[flybytaco]

curious. which con rod/piston are you using in which combo

edit :

hang on, if i've read this right if i used the rod/piston front the powerking with my skyhawk i can get the same effect ?

i used the piston,cyl,head from power king the rod and bottom end skyhawk also changed the wimpy top bearing with the nicer pk one adding the billet intake the racing carb and a chrome gen3 pk muff I baught 2 new motor kits to do this lol need to order a pk piston now to build the pk bottom end with the skyhawk top end because the pin height is to high so the piston doesnt go to the top of the jug its too short.. where can i get a pk piston?

 

[Bikeguy Joe]

Have you measured the bore and stroke yet?

 

[Bikeguy Joe]

What were the SkyHawk's stock measurements?

 

[flybytaco]

i beilieve the stroke is 40mm so now if i'm correct on the 40 mm thing it's now 44mm dont know the sroke of the pk but its 68.5 cc

 

[flybytaco]

 

[camlifter]

i did something similar to a jet 80, not stroking it. but i added a spacer under the jug raising it .125", then cut .125 off of the top of the jug, there by raising the ports .125", increased the bottem end and mid range power without hurting the top end any. just make sure your not letting any over lap into the port timing. when the piston is at bottom dead center you should not be able to see through the intake port into the cylinder.

 

[flybytaco]

ok so this motor is the fastest one i've ever built. i let my friend ride it and he said it screws lol I was in the dirt earlier racing him and was passing him slidin out sideways like he wasnt really moving. he has a gen2 a 58cc starfire which revs to the moon. but this beejet revs right there with it and pulls the only mod i did to the cylinder was widened and tapered off the exaust port and chamfered the edges of all the ports. did not raise any ports..

 

[motorhead419]

All's you need is a 18mm Mikuni and then open up that small hole in that straight intake..I did it and mine screams now.

 

[flybytaco]

nah its good enough here If i want more I'll hop on the cr250 or my nsr50 that has a 24 mikuni flat with 25$ a gallon mr9 87 octane does 70mph lol love it

 

[flybytaco]

Have you measured the bore and stroke yet?

OK JOE THE SKYHAWK IS STROKE 37MM BORE 47MM the jet is 47mm x 35mm weird itsa short stroke

 

[Bikeguy Joe]

So it isn't a stroker, it's got a shorter jug on it with the spacer you made to compensate for it, and altered timing, correct?

 

[Bikeguy Joe]

That comes out to 51cc for the skyhawk, and 45cc for the other assuming a 2 mm deck height.

 

[Bikeguy Joe]

It's more like 8mm.
6.5 : 1 compression ratio.

 

[flybytaco]

the jug isnt shorter the pin heights on the pistons are diffrent

 

[flybytaco]

the skyhawk piston wont work in the pk the skirt his the crank at bottom of stroke put a pk piston in and it was fine ith the skyhawk jug put that motor in my cranbrook. runs like a jet lol

 

[flybytaco]

OK JOE THE SKYHAWK IS STROKE 37MM BORE 47MM the jet is 47mm x 35mm weird itsa short stroke

sorry the skyhawk was 47 bore 38 stroke

 

[Riding Rich]

Camlifter

i did something similar to a jet 80, not stroking it. but i added a spacer under the jug raising it .125", then cut .125 off of the top of the jug, there by raising the ports .125", increased the bottem end and mid range power without hurting the top end any. just make sure your not letting any over lap into the port timing. when the piston is at bottom dead center you should not be able to see through the intake port into the cylinder.

If i remember correctly the intake port is allmost completly open at BDC.
I'm confused here.
Raising the jug i'm sure is needed but this would open the port more.
About put the top of the piston flush with the bottom of the port at BDC.

Iv'e even heard of people filing down the top of the piston to somoothe it out.

Am i thinking wrong here???