How big is my bore kit!!!need help

[Bryan]

how do i tell what bore kit i have in my blaster. i bought it off a guy and he said it had a .40 over but how can i make sure thats what in it. i have to buy i new gasket kit and i dont want to buy the wrong one. can anyone help me thanks

 

[sheeblast]

for an overbore, the gasket kit shouldn't make a difference.
but to check the size, take a micrometer, a measure the diameter of the cylinder walls.

 

[JonS]

take it to an autoparts store or local mechanic. they may be able to help you. i did that with my warrior jug.

 

[4cfed]

or messure it with a tape messure and convert the cm to mm

 

[sheeblast]

hard to get an accurate reading with a tape measure, a micrometer will give you the best reading.

 

[Bryan]

What is stock size

 

[sicivicdude]

66 mm for a true stock bore.

72mm for a "stock" big bore kit.

Yay! 1,000

 

[acezeesawtooth]

i believe the gasket kits are the same size for all the stock sleeve cylinder bores. the only thing you should need to know the exact size for is if you need a new piston new rings or a new bore. and dont they usually stamp it on the top of the piston

 

[kyle24]

you can use a pair of calipers most auto parts shop like advance auto auto zone or napa have them behind the desk take the jug into the and have them measure the bore standard bore is 66mm which in inches rounds out to 2.6 how you get that is what ever millimeter they give you divide it by 25.4 and it will give you inches or the opposite if they give you inches multiply it by 25.4 and that will give you your exact size

 

[N8tsNastyBlasty]

checking it at the top of the bore isn't accurate if u have excessive wear below the where the rings stop( i just learned that lesson ) but an in expensive set of bore gauges coupled with a micrometer is invaluable! I spent at least 2 hours measuring three different jugs this time.

 

[Budget_Blaster]

Yea you got to have the proper tools this area is where you want to be precise.if budget is a factor try harbor freight or other type of tool company.

And take multiple measurements at different areas to insure you get an accurate measurement.

 

[sheeblast]

checking it at the top of the bore isn't accurate if u have excessive wear below the where the rings stop( i just learned that lesson ) but an in expensive set of bore gauges coupled with a micrometer is invaluable! I spent at least 2 hours measuring three different jugs this time.

if it takes you 3hours to measure the bore of a jug, you aint doing it right.

 

[N8tsNastyBlasty]

i was more or less practicing with my new tools and measuring all aspects of the cylinder. I haven't much experience with a bore gauge and was taking multiple measurements to ensure consistency.the allowable tolerances are pretty fine on the bore. I also used it to help figure exhaust time area (not port timing) and check i.d's on the intake to get an idea of what needs to be removed to fit my cr125 reeds. It's a learning process. I've never claimed to be an expert but i like positive input from those who do, thanx