JE pistons?

[RM125]

Just bought a top end kit for my RMZ450 off Trade Me it's a forged JE piston ups the compression ratio is it correct that these need no jetting just install and ride? Goes from 11.9 : 1 to 12.8 : 1 don't want to blow it up!!!

[DocT]

You will probably have to re-jet

[kezzafish]

Secondfield has a JE in his 05 RMZ450 and hasn't touched the jetting, his piston increased the comp. ratio but i don't know by how much, PM him, he'll be happy to help. It will be fine just run it

[scott411]

i went bigger on the main jet when i upped my compression in my 06 rmz450,

[theblacksmith]

Stroke and displacement remains the same - however if compression ratio rises I would suggest higher octane fuel to prevent pinking or pre ignition - 96 or 98(which you probably use anyway) What does the Suzuki manual suggest you use?

[Reckless]

i went bigger on the main jet when i upped my compression in my 06 rmz450,

I was going to suggest higher compression prob means more heat and a bit more fuel might be the go.
Definatly see how its running and have a fiddle anyway?

[secondfield]

Mine worked out sweet, it does run a bit richer ive noticed though ... installed a fuel screw while i was at it. Stock jetting with the screw wound right up (lean as) and its still running a bit rich. Gonna change the needle position in the carb, running the bike on BP98...

[theblacksmith]

Mine worked out sweet, it does run a bit richer ive noticed though ... installed a fuel screw while i was at it. Stock jetting with the screw wound right up (lean as) and its still running a bit rich. Gonna change the needle position in the carb, running the bike on BP98...

Sounds good. What about running temp - same?

[secondfield]

Yep, I wouldn't be 10% sure without a temperature sensor ... but I have had no issues with it boiling in the tight nasty stuff, runs cooler than my old exc400 did. Tommorow will be the test - links track in karipoti ....

[Motoxparts]

JE pistons can run higher than stock with std jetting it is the way the crown is designed and squish area good piston manufacture knows what they are doing not like a cheap made stock cast design pistons and also it is were the rings a placed to transfer the heat from the piston to the cylinder to the water jacket JE has a lot better ring area, www.motoxparts.co.nz
and we have 25 years machining building performance engines.