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1992 yz 250 cylinder comparability

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Hello, i am a long time lurker on these forums and i have recently decided to join the community. Last week i got a 1992 yz 250 for free from a friend the good about it is the bottom end and transmission is in great shape the frame and brakes are decent the bad is the cylinder got taken out by the last failure. Im looking to see what other years cylinder might fit, and if i cant find one should i get it re sleeved?IMG_5705.JPGIMG_5706.JPGIMG_5704.JPG

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Would either of those be better than getting la sleeve to put a fresh sleeve in and final hone it to the piston? Im kind of new to the whole nickasil vs cast iron sleeve

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Ideally, you want to get the cylinder Nickasil-ed. A good plater should be able to clean up the bore, replate, and get a matching piston without much trouble. They may have to over-bore it (depending on damage to the cylinder), as long as a matching piston can be found.

A steel sleeve does not have the heat-transfer capability of Nickasil, and is generally considered a down grade to a motor.

Cool project! Keep us updated on what you find. :thumbsup:

Edit: Looking at the pictures again seems to show that your cylinder has a sleeve in it. This was probably the stock design, before Nickasil was widely used. In that case, a new sleeve is your only choice.

Edited by CaptDan
Second look...

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You would be wrong the yz 250 started using plated cylinders on the 88 model year. So that cylinder has been sleeved in the past. Not only does a sleeve suck on heat transfer and the added weight. 

Many times when a plated cylinder is sleeved like that the port alignments become mismatched effecting performance negatively. Plus a sleeve maybe cheaper in the immediate but a plated cylinder will wear and last much longer and offers better tighter clearances which means better power. 

Edit: 

I'm not positive on this but I thought other years would work on that style of yz 250 engine. Yamaha was using 94 cylinders on the 98 team bikes. I think the only difference between the years was porting specs. May have to make sure they didn't swap from a domed shape piston to a flat top piston if they did you need the head to match. 

Yamaha is pretty good at recycling parts between the years. 

 

Edited by SmokinJoe90

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Thanks for all of the replys, I'm seriously thinking about the used cylinder now considering the plating is better than a sleeve. I need to take more pictures of the frame as it sits, i know most forums love pictures.
IMG_5708.JPG

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An update on progress, im most likely ordering a bottom end gasket set and re sealing the bottom end. I already have to clean it out but everything seems to be nice and tight. Its torn down as far as i can get without a flywheel puller

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I would get a puller if you can or borrow one. You can rent a steering wheel puller from autozone and bring it back after.

I would also make sure the con rod isn’t bent. It looks to me like the piston smashed the hell out of the port. I would say there’s a good chance it may have bent the rod as well.

You have a nice project there and you shouldn’t lose your ass on it even if it needs a complete rebuild. I’ve been dying to find a 93-95 125 or 250 for a cheap project and none seem to be out there at the moment in New England. I love how they look and the pink and purple seat covers are ultra retro to me.

Good luck! You’ll have a nice bike before you know it.

Edited by MaybeMe
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I would get a puller if you can or borrow one. You can rent a steering wheel puller from autozone and bring it back after.
I would also make sure the con rod isn’t bent. It looks to me like the piston smashed the hell out of the port. I would say there’s a good chance it may have bent the rod as well.
You have a nice project there and you shouldn’t lose your ass on it even if it needs a complete rebuild. I’ve been dying to find a 93-95 125 or 250 for a cheap project and none seem to be out there at the moment in New England. I love how they look and the pink and purple seat covers are ultra retro to me.
Good luck! You’ll have a nice bike before you know it.

I got really lucky on this one, my friend had a Lincoln town car with turn signal issues and i diagnosed and repaired it with parts he got in trade for the bike, the only things keeping me from riding it is an engine and chain rollers. He also gave me a service manual and brand new front tire with it. Im going to get the bottom end done hopefully this week and order my cylinder jug and piston
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Thanks for the update, Mag liter!

Sorry about posting that your cylinder came stock with a steel sleeve (and thanks for catching it, SmokinJoe90 :thumbsup:). I knew it was just a guess, and I usually try to state that I'm merely guessing -- just throwing ideas out as possibilities.

At any rate, your crankcases were shared with '88 thru '96 YZs (and '97 WRs) according to the parts lists, so the cylinder bolt pattern (and base gasket) will be common with those bikes.

https://www.partzilla.com/product/yamaha/2VM-15121-03-00?ref=ec3af27955d7a42a608f01edc86322f92d0cc9ae

https://www.partzilla.com/product/yamaha/2VM-15111-06-00?ref=ec3af27955d7a42a608f01edc86322f92d0cc9ae

 

The power valve mechanism cover is common to the '90 thru '98 YZs...

https://www.partzilla.com/product/yamaha/3SP-11992-11-00?ref=00d50b0f9d8c836dffbd83af17f72830ce3611fe

 

Like Joe said, you may be able to get a '93-'95 cylinder to fit (don't bother with the '96-'98's).

And Wiseco says the same piston fits '92-'98 YZs...

https://www.wiseco.com/ProductDetail.aspx?ItemID=677M06800&ModelID=458&ModelYear=1992&AppID=2381

...so that's a good sign. :thumbsup:

Good luck!

Edited by CaptDan
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Thanks for the update, Mag liter!
Sorry about posting that your cylinder came stock with a steel sleeve (and thanks for catching it, SmokinJoe90 :thumbsup:). I knew it was just a guess, and I usually try to state that I'm merely guessing -- just throwing ideas out as possibilities.
At any rate, your crankcases were shared with '88 thru '96 YZs (and '97 WRs) according to the parts lists, so the cylinder bolt pattern (and base gasket) will be common with those bikes.
https://www.partzilla.com/product/yamaha/2VM-15121-03-00?ref=ec3af27955d7a42a608f01edc86322f92d0cc9ae
https://www.partzilla.com/product/yamaha/2VM-15111-06-00?ref=ec3af27955d7a42a608f01edc86322f92d0cc9ae
 
The power valve mechanism cover is common to the '90 thru '98 YZs...
https://www.partzilla.com/product/yamaha/3SP-11992-11-00?ref=00d50b0f9d8c836dffbd83af17f72830ce3611fe
 
Like Joe said, you may be able to get a '93-'95 cylinder to fit (don't bother with the '96-'98's).
And Wiseco says the same piston fits '92-'98 YZs...
https://www.wiseco.com/ProductDetail.aspx?ItemID=677M06800&ModelID=458&ModelYear=1992&AppID=2381
...so that's a good sign. :thumbsup:
Good luck!

Thanks for the additional information, i have ordered my crank seal kit and a flywheel puller and i hope to split the cases to clean and re seal it next week sometime. Then all thats left is a cylinder

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9 hours ago, Mag liter said:


Thanks for the additional information, i have ordered my crank seal kit and a flywheel puller and i hope to split the cases to clean and re seal it next week sometime. Then all thats left is a cylinder

Do your crankcases have a gasket in the middle or is it sealed with Yamabond?

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Do your crankcases have a gasket in the middle or is it sealed with Yamabond?

I honestly dont know, the service manual referenced using Yama bond 4 for sealing it. I played it safe and ordered some just in case. I will post back here with any findings i have when i get my gasket kit

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1 hour ago, Mag liter said:


I honestly dont know, the service manual referenced using Yama bond 4 for sealing it. I played it safe and ordered some just in case. I will post back here with any findings i have when i get my gasket kit

When you tear it down, you will see if it had a gasket or yamabond. If it’s yamabond, you want to match the cases on a flat surface and then use yamabond to seal it. Make sure the crank and everything goes together, then split them again to seal it. It can get messy if you don’t.

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Ordering a cylinder off of ebay in the next few days, once the cylinder comes in i will measure for a wiseco single ring piston

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Wossners are good pistons very much like a wiseco. Wiseco made in China wossners probably same place maybe they are still made in Germany either are good quality is the same.

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