Boring 200x to 66mm .. do I need to change the jets.

**86trizinger** · 03-13-2010, 07:42 PM

I just got my piston in the mail for my 200x.. Its a .040 66mm piston.. Had to go that large due to the current size. Stock cylinder was sleeved so I was told I should be fine.

I am also redoing the head as well with new valves and some ports cleaned up a little.

Do I need to rejet the carb to match the piston? please let me know.
Thanks

**Mr_RPM** · 03-13-2010, 08:19 PM

your going to 56mm, whats stock? is the compression the same as stock? your cleaning up the port, does this mean making them a bit bigger? im gonna say you might need to jet up, but just a little not much. unless your playing with the exhaust, carb or intake jetting wont need to be raised to much if any.

**86trizinger** · 03-13-2010, 08:37 PM

Compression is stock as far as I know but it may raise due to larger piston a very little bit.. Stock size piston is 65mm. So its a a full 1mm over bore. 66mm
More of just polishing the ports up some.. Not much porting .. just want to match the polished combustion chamber

Exhaust will stay stock for now.. Has ITG filter on it already.

**shortline10** · 03-13-2010, 09:05 PM

I'm confused a stock bore on a 200x is 65mm . Is it April 1st or what .

**RodKnockRacing** · 03-13-2010, 09:33 PM

he must mean 66mm

**86trizinger** · 03-13-2010, 10:39 PM

Yeah sorry I meant 66mm... I just didn't realize it

**Mr_RPM** · 03-13-2010, 10:49 PM

1mm bigger wont raise the compression much, not that compression even effects jetting that much. basically i see no reason to jet in this thread

**86trizinger** · 03-13-2010, 10:57 PM

Great Thanks

Thread: Boring 200x to 66mm .. do I need to change the jets.

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Boring 200x to 66mm .. do I need to change the jets.