colin wood

Member
Nov 10, 2001
16
0
WHEN INCREASING THE STROKE ON A TWO STROKE . IS IT BETTER TO RAISE THE BARREL OR MACHINE THE HEAD .WHAT EFFECT DOES IT HAVE ON IGNITION AND PORT TIMING.I AM WANTING TO CHANGE THE STROKE A TOTAL OF 1MM.
 

MikeS

LIFETIME SPONSOR
Jun 12, 2000
716
1
Most go more than 1mm when going thru all that trouble.

Most tuners run some sort of software that give them the optimum port timing.

It is easy to get a spacer or triple up base gaskets to try raising the barrel. I would say this would add good power mid to top generally. Maching the head would tend to add low to mid power. I can be wrong but from the research I did for my specific application that is what I found
 

dirtbikr99

Member
Nov 21, 2002
180
0
i have a 02 cr 134 2mm over bore and i want to stroke the crank shaft, but i have alot of questions like how far to stroke it, also will the pistion need to be cut to clear the crank also if i use a spacerplate, the power valve linkage will not reach to connect. so i was wondering what other people have done with a similer bike, i could just cut and weld it longer??? also if i make the spacer plate the same height as the inclrease in stroke if the port timing will still be perfect???? and any other info?!?!?!??! thanks alot
 

jaguar

~SPONSOR~
Jul 29, 2000
1,466
79
South America
cut and weld

it throws the port timing off. best to get a degree wheel and map out the port timing on your stock setup first and then after the mods you can fiddle with cylinder height and porting to try to approximate what it had before.(degrees BTDC BBDC when the port opens)
 

splatt

Resident mental case
~SPONSOR~
Dec 1, 2001
906
10
Isn't a piston available with the correct wrist pin height?That's what I do with stroker engines that I build for automotive applications.

 

Steve
 

cujet

Member
Aug 13, 2000
826
5
Installing a stroked crankshaft is easy. However as mentioned above, it is very important to port the cylinder to your needs. How you go about getting the proper port timing will be driven by your porting needs. With such a basic question like the one you asked there could not be any answer other than the one I gave.

If on the other hand, you are talking about a specific, well known engne. AND one that is typically modified in certain ways. And have a specific torque curve in mind then that question could be answered by those with the experience on that engine.

Try to be very specific in your question and you may get the answer you are looking for.


Chris
 

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