big bore kit help

[pickles09]

i hav a Yx 140cc if i buy this would i need a new head or will it adapt to the 146cc bore?

heres the link:

NEW 146CC TB BIG BORE KIT FITS JIALING 125CC YX 140CC - eBay Other Makes, Bike Parts, Motorcycle Parts, Accessories, Cars, Bikes, Boats. (end time 02-Dec-08 19:29:00 AEDST)

 

[Dabomb]

im preety sure that will fit ur head, i got a big valve lifan one and its alrite.

 

[Andrew Aslan]

well it says it fits straight on to a yx 140cc.. so i am guessing yes.

 

[no_crf50_here]

Those guys are a class act. I've got a kit off them, opened box and NO HIGH COMP piston just a stock flat top piston, won't return emails. But they fit straight on

 

[tormentandglory]

Is it really worth it? $114 for an extra 6cc.

 

[no_crf50_here]

nop, but i expected higher compresion - ooh well ebay will always be ebay

 

[Dabomb]

hmmm wat compression we runnin in the 146..... 9:1?

 

[no_crf50_here]

by now i'd say mine would be running 3:1 if i'm lucky How do you work it out anyway?

 

[Dabomb]

need measurements of piston deck height and all that crap.

 

[tormentandglory]

by now i'd say mine would be running 3:1 if i'm lucky How do you work it out anyway?

You need to buy yourself a burette and measure the combustion chamber volume, and work out the piston crown volume. And you need to mathematically work out your squish clearance volume. Get yourself a copy of a book called "4 stroke performance tuning" by alexander graham bell. Its the horsepower bible and will teach you all you need to know.