yz80 big bore - need advice!

[123ozzie]

I recently bought a yz80 that needs cylinder work. I found a company (Kustom Kraft in Colorado) that sells a 110 big bore kit. I've heard that this will require rejeting the carb. Does anyone have any advice on what size main jet to go with? Also, will I have to replace the pilot jet, jet needle etc. ? This is a project bike that is just rode for fun, and not raced. Any help would be greatly appreciated. Thanks, Jeff

 

[robwbright]

I have no idea about that kit, but on my 144 big bore I lowered the needle clip one clik, messed with the airscrew and it was about the same as before.

 

[chevy383cid]

I'd say your going to need to try 2 sizes smaller on the main and the same if any on the pilot, needle- try diffrent clip positions.I big bored my yz125 last year(at KK) and had to lean my jetting down two sizes on the main, Kustom Kraft is a good company!! My cylinder for my kx is there as we speak,getting renicasiled!!

 

[robwbright]

As far as my situation, Eric Gorr told me that the combination of all the factors with his work on my motor worked together to keep the jetting pretty close to the same (i.e. bore, head work, port, etc. . .).

 

[gwcrim]

Sorry to say, but it's nearly impossible to jet a motorcycle on the internet.

I punched out my 500 to 520 and never touched the carb.

 

[Motobro-angel]

You don't have to re jet it..
It depends on your elevations