Tri z cylinder sleeve

[Jcormode]

Okay, after rushing about and forgetting to tighten up the rubber boot on the rear of the carb shed sucked in a load of gunge and ruined my barral I'm struggling to find a new sleave for it. Any one used those eh imports sleave on eBay? I'm not a lover of buying cheap cr@p but I'm stuck its already 68.5 over bore and don't think there's much left to hone out.
Ideas?

[El Camexican]

You could call Mark at the number on this site, http://kustom-kraft.com/ I am pretty sure he ships to your side of the pond. He'll explain your options, but my thought is to buy a cylinder on ebay over here http://www.ebay.com/itm/C-1985-YTZ250-Yamaha-85-250-Tri-Z250-cylinder-/350657332109?pt=Motors_ATV_Parts_Accessories&hash=item51a4ce438d&vxp=mtr and have it mailed to him to work on and then have him mail it to you all cleaned up with a new sleeve and piston. That is how I usually do it from here as shipping is often more than the parts. He's on West coast time. Good luck.

[Jcormode]

I can have it installed no probs and my cylinder has had work done to it so Wana keep it. Ill give him a try though and see if he can just make one and send it me.

[TimSr]

Okay, after rushing about and forgetting to tighten up the rubber boot on the rear of the carb shed sucked in a load of gunge and ruined my barral I'm struggling to find a new sleave for it. Any one used those eh imports sleave on eBay? I'm not a lover of buying cheap cr@p but I'm stuck its already 68.5 over bore and don't think there's much left to hone out.
Ideas?

Wiseco makes pistons for overbores up to 70mm.

LA Sleeve and Wiseco both make sleeves for it.

[the otha tri-z]

Wiseco makes pistons for overbores up to 70mm.

LA Sleeve and Wiseco both make sleeves for it.

Agreed, go to Wiseco's website and check out their other piston sizes. If it were me I would personally not re-sleeve yet. I would bore up to 69mm and just get a new piston. I found my last Z wiseco piston on ebay for about $50 less then wiseco.com's price.

[3 Wheel Drive]

Yeah bore that up and feel the full 250cc, get your money's worth outta that jug!

[Jcormode]

My apolajise'z its 69.5 I have heard you can go to 70 mm but have to mill the head slightly.
Wiseco sell standard size sleaves???!!!! Awesome IDE prefer to get a desent one, ill go with that ATM

[the otha tri-z]

My apolajise'z its 69.5 I have heard you can go to 70 mm but have to mill the head slightly.


Yes that is correct. I had to do that on one of Z's in the past, but well worth the extra $40 at the time to get one last bore out of the jug.

[TimSr]

My apolajise'z its 69.5 I have heard you can go to 70 mm but have to mill the head slightly.
Wiseco sell standard size sleaves???!!!! Awesome IDE prefer to get a desent one, ill go with that ATM

I've never had to mill a head or use anything other than a stock gasket. I always used Wiseco (Cometic) head gaskets for TriZ.

Both LA Sleeve and Wiseco make sleeves for stock bore. According to the guy who did my last resleeving, LA Sleeve is far preferable to work with, far tighter tolerance in uniformity of centering and wall thickness. Hard for me to imagine Wiseco being substandard though.


If you do releeve to stock bore, get OEM Yamaha stock positon and rings if possible. They are common on ebay. Cast OEM pistons do not swell as much from heat, and are bored to smaller clearance which makes maintain higher compression when cold, less prone to cold seizure, and your bore will usually last longer as cast pistons are softer material.

[Jcormode]

Yea well that's what my intention is to do, buy a good sleave that my engineer can install here and start a fresh with yam piston, going to go with 70mm wiseco like you say and see how it goes.
So if you don't need to mill the head, where's this rumour come from that I've heard not only on here but my yam dealer has said it also, don't get me wrong, I'm over the moon to hear that I can overbore one more time and save the struggle of new sleave, I just don't want to build it and blow it again. Don't think I could handle fixing it again so soon AGAIN ha.

[Jcormode]

Just to add for anyone else, kustom Kraft can't do off the shelf sleeves for z's but like you've said la sleeves have got them at a desent price

[Jcormode]

Hey Tim just built up 70mm engine the other day, ran it in nicely went well, I took her for a blast this morning and looks like the head gasket has gone on me, head nuts are tight. Any advise?

[Bryan Raffa]

I never had to mill a head ether ... only to bump the compression up.

[Jcormode]

Ok, I've took head off and has got a hair line crack down it on the dome 161232
I've been and got another gasket and its 69.3 diamiter and if I look closely the piston hits the gasket I've rung around and that's the only size I can get oem or after market for that matter. BUT I have found an old one in the draw that isn't oem in half desent condition that is measure ing 70.3mm so I'm going to give that a try??
It also looks like the sqish band is that tight its causing detonation. I'm only a bricklayer and old this jargon is baffling me lol going to try this second hand one in it and if that one goes I'm starting with a fresh barrel.
What about doubleing up on base gasket??

[Bryan Raffa]

LISTEN THATS A YZ HEAD GASKET .. get a metal tri z gasket get a new head... stock.. and torque it to 22ftpnds:D

[Jcormode]

I new ide get help from you Brian! Top man, I've never been able to buy a Tri z gasket? Always had to biy the yz one, I thort everyone did that?! I take it from your post I'm wrong. Could explain a lot !

[Jcormode]

Yep just spoke to yam and ordered one. Quick one, are wiseco and prox the same size pistons? Ie 2mm overbore sounds like a stupid question but I'm sure your used to answering my stupid questions by now lol
Reason being is that with you saying about yz being different the shop that honed my barrel out has sold me yz piston aswell as gasket and I think I've been b@mmed because my prox ( old tywan stock) piston shows the piston walls out of the barrel I've just noticed? And I'm sure there supposed to be flush?!

[Bryan Raffa]

yes wiesco and oem/ stock pistons are different sizes... going from a stock piston.. you must hone or bore it out for a wiesco.. lets see the piston score marks.

[Jcormode]

161274 161274

[Jcormode]

161275 looks like detonation. I think?;)

[Jcormode]

I'm sure there so posed to be flush?161276

[Jcormode]

161277 161278 161279
Gota be that gasket that's made the squish thingy to tight and detonating? But I never thought that the piston was higher? Measures 26.9mm from top of gudgeing pin to top? Sound right/wrong?

[Bryan Raffa]

with the base gasket on the cases. piston on .. it should come up flush.. wrong piston .. or someone decked the cylinder. to me looks like wrong piston/ head gasket. stock cyl is ,, roughly 126.9mm from top to bottom..

[zmpolaristech]

I thought YZ pistons had a bit taller deck height than the tri-z pistons, but I could be wrong here.

[MTS]

Do you have a picture of your cylinder head perticulary the dome? that is sticking way up there,,moreso than the .060 sqish area of a stock Z head with a gasket im suprised it turned over at all. it looks like the wrong piston,i think 88 or 7-9 YZ went to a 125mm rod insted of 130mm 83-86 should be the same if i remember right. could be a year newer piston in it, ment for the longer rod. do the bottom of your transfer ports lign up flush with the crown of the piston at bottom dead center??

[Jcormode]

161377 this is the one that it was running with. It ran great thru the running inn time and for around 30 mins first run but I got stuck in a snow drift and reved it and that's when it popped into water jacket. The barrel is 126.3 ish, I was in a bit of a rush. I've another head which I ran when I first built it and I've tried it today with an old gasket that was 70.6 internal diameter but blown so coated both sides with instant gasket and tried that to no joy. Also tried two base gaskets to compensate the tall piston but still nothing. The piston box says 83-85 yz 250 and wrote on 'for Tri z'.
I can't remember if I've already asked this but Can i get a Tri z piston 70mm as like I've said before I've always used 85 yz top ends and now I just want it finished.
Cheers lads. Appreciate all your help.

[MTS]

Is there anything left of your lower connecting rod bearing?? it looks like it came apart!! can you move the rod up and down with your hand while the crank is stationary??

[Jcormode]

No the pits are from someone else. Rod and bearings seam good. The thickness of the yz gasket took the brunt of the piston so I was lucky in that respect. I'm gutted today as the snow has fell heavy and all I've got to play on is the banshee with rubbish tread on tyres so looks like ill be at the back of the pack ;(

[volfan537240]

Lots of good info in this thread :TrikesOwn

[Jcormode]

161481 my mistake 83-87 piston on the look out for a new head that I can then change all the stuff hopefully I can get a wiseco/ wossner piston to fit (with a possible bit of honeing) then proper gasket and new head I should be well on my way but if the other pistons are smaller in diamiter I may be having to resleave as originally planed. Anyway ill keep you posted with how I get on.
Cheers

[Jcormode]

A little update on this,
Yes zmpolaristech the deck hight is slightly taller on the yz you can get away with it on all sizes up to 69mm with yz gasket but if you go bigger you have to mill the head out at the sqish band, Tri z piston and Tri z gasket WILL hone out to 70mm without any alterations.
With me being a tight wad I am in the process of having the head milled out to 70mm+ by terry Sylvester himself an old skool racer now his sons mechanic and yam dealer. so I can run this yz piston with 2 base gaskets and Tri z head gasket as the yz head gasket is 69.7ish and the Tri z is 70.3ish
With all my mistakes in buying wrong stuff after listening to supposed professionals at the shops that I have to deal with I hope that no one else makes the same mistakes I have.
Don't even if it runs yet lol but should be fine