Bore question for you guys that know

[1998yamahawarrior]

Ok Ive got the jug that was bought as a 84mm bore. Well I took it into auto tech today with me to check, before I even fully decide on a piston. Well after a few checks at different places it averaged 85.979mm (3.385in). Not knowing exactly what the exact bore needs to be for each piston size I need one of the knowledgeable peoples input. Any help would be great, I know theres a couple guys that know this really good.:atv:

 

[1998yamahawarrior]

I know its only been an hour, but Im bumpin this up.

 

[elwood]

isn't a 366 85mm? that jug may need resleeved or hell I could just be having one of those days

 

[1998yamahawarrior]

Well here's the catch, that measurement was done using a telescoping gauge and read with a 3-4 inch micrometer. My instructor needed to recalabrate the metric one. So we did the standard to metric conversion. I guess what I really need to know is what the rough measurement of the 85mm piston is to judge the cylinder to piston clearance and see if its good to rock.

 

[1998yamahawarrior]

Oh and if it needs a resleeve I'll be a little pissed, like I siad it was bought off a member and was only supposed to be 40 over

 

[1998yamahawarrior]

With the guys that have done the 366, some one has to know a little info.

 

[elwood]

got this off the JE site, http://www.jepistons.com/Products/XC8500.aspx it's the specs for the rings on the 366, they should be able to tell you all the info you need here is their email and phone list http://www.jepistons.com/AboutUs.aspx

 

[headache]

85mm is 3.3465" thats what i bored my cylinder to run my JE piston. 3.385 is 86mm.

 

[Hdale85]

So maybe he could run an 85mm piston then?

 

['00 WO-YA!]

Well, I'll give ya this, hope it helps. Stock bore size is 82.97-83.02mm or 3.267-3.269. Figure each mm is about .040 over. Piston clearance is .00157-00236 so one & a half to nearly two & a half thou. Sounds like you're way outta spec for what is supposed to be a 84mm jug.

 

[1998yamahawarrior]

Well we made 10 to 15 measurements in various parts of the cylinder and it didnt very much, maybe a .001 of an inch.

Well, I'll give ya this, hope it helps. Stock bore size is 82.97-83.02mm or 3.267-3.269. Figure each mm is about .040 over. Piston clearance is .00157-00236 so one & a half to nearly two & a half thou. Sounds like you're way outta spec for what is supposed to be a 84mm jug.

I got the stock specs to, but JE pistons may not have the same specs.

85mm is 3.3465" thats what i bored my cylinder to run my JE piston. 3.385 is 86mm.

Its not quite 86 but damn close. The sleeve looks plenty thick yet

 

[1998yamahawarrior]

Hell does anyone make a 85.5mm piston for the warrior

 

[elwood]

not that I know of

 

[elwood]

honda 400ex, 400 rancher and yamaha 450 Wolverine, grizzly, and Kodiak can run 85.5mm but I don't think and would work for you or would be too much work to retrofit it

 

['00 WO-YA!]

Piston clearance for a forged piston will be a lil loser but it had better not be very far off of that stock spec or you're gonna have piston slap! I'm gonna say that the loose side of the stock spec is prolly pretty close. Note that I said "close" not exact.

 

[1998yamahawarrior]

Im getting less happy by the minute, this jug was supposed to make my biuld a little easier.

Im assuming 86mm rings with the same dimensions would not work just thinking about it. I might email JE and see if the can help.

On the cylinder sides still looking relativity thick yet does anyone have a spec for it. I cant find one.

 

['00 WO-YA!]

Call & talk to Greg @ CWR & see what he says.

 

[1998yamahawarrior]

Sent him an email, since all my free time is after most places close.

If I cant figure out something, I guess I have a piece of scrap and will end up boring my original jug.:argh:

 

[1998yamahawarrior]

Greg got back to me, I need to bring it back up to school and measure the sleeve thickness. If its still thick enough, Ill just hone the cylinder and order a custom piston.

 

[duneracerweston]

Coool you be running a 370 that would be cool