366 JE piston ring gap question?

[1998yamahawarrior]

Well Im getting ready to assembly it as far as I can while I wait for the head to get done. Got looking at the spec sheet that came with the piston and they have all the info, but the ring end gap specs. Since I know we have a few guys running this same piston Im reaching to you for help. Did a search on thier site and here and no one mentions anything. Thanks Guys!!!!

 

[1998yamahawarrior]

I found Wiesco's formula for figuring ring end gap. If I use theres the top ring would be .013 and the second would be .016 . Wiescos formula is bore x .004 for the top ring and bore x .005 for the second. I got those by using the 85mm converted to inches. Obviously if that sounds right Ill do some measuring to have the exact bore.

 

[1998yamahawarrior]

Anyone have any input?

 

[lbjamm]

Ring gap, shming gap, just install the things. JK. Sounds like you're pretty close to me.

 

[1998yamahawarrior]

Thanks for the input LB, hopefully one of the guys that has done the 366 chimes here soon. Hoping to get it setup tomorrow.

 

[88WarriorBoy]

get a hold of beastly then lol he is probaly on facebook right now anyways

 

[beastlywarrior228]

Ya it's been awhile I'm not 100% what it was right now

 

[lbjamm]

Hey 98, check JE's website in the tech section there are some formulas. Seems like they pertain mostly to automotive apps but they do have smaller bores on there.

http://www.jepistons.com/PDFs/TechCorner/SCPDrawings/piston_instrc2618.pdf

 

[1998yamahawarrior]

Ive been on there and the problem I have with them not specifying a powersports application is that we can turn more RPM's and generate a good amount of heat compared to a car. I sent an email to JE tech support, but if anyone has the specs before they get back to me it would be great.

 

[lbjamm]

I understand

 

[lbjamm]

Sometimes those companies take a while to answer. I e-mailed Hotcams and they mailed back the next day. Yesterday I called them about timing my Hotcams in the YFZ and I got an immediate answer. I hope they get back to you soon. GL

 

[DeadLastRacing]

the formula is bore x .0055 inches

I just pulled the spec sheet out on my brand new 366 JE piston box, no ring gap spec on it anywhere.

If the rings came with it (JE part number XC8500) just put them in and make sure that the slits are opposite of each-other.

This might help too - http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

 

[1998yamahawarrior]

Ya dean that wiesco link is how i came up with the measurements last night.

 

[1998yamahawarrior]

Thanks for all the input guys!!! they spec'd out without any work.