help idetify piston

[thumpers4ever]

I am rebuilding a 87 250r that I got that was in pieces. I tore the engine down and can't find out what piston was in it. I think its a Wiseco cuz it has a little w on the under side. on top of the piston is marked H41A0, and underneth is 562. I searched Wiseco web page and couldn't find anything.

Also with some research I discovered by the serial # that my cases are 86 but the cylider is a bridged intake so that makes it 87-89, right. there is no space plate so I asume the crank is a later crank. any help would be great.

[thumpers4ever]

pic of bottom

[thumpers4ever]

another pic

[hartwill]

maybe I am wrong but I think that is an 86 piston because of the window. in 87 the skirt had like a half moon cut out for intake. but don't quote me it could be the other way around. and the case could have been broken and replaced so you can't really go by those numbers all the time I would say check the crank and go from there. but other people on here are much more knowledgeable than me so listen to them.

[fearlessfred]

Originally posted by hartwill
maybe I am wrong but I think that is an 86 piston because of the window. in 87 the skirt had like a half moon cut out for intake. but don't quote me it could be the other way around. and the case could have been broken and replaced so you can't really go by those numbers all the time I would say check the crank and go from there. but other people on here are much more knowledgeable than me so listen to them.
just the oppisite.i thinkeverthing thumpers4ever has stated is correct. i do believe that is an older style weisco,there is a couple of guys on here that will know for sure,but far as everthing else it has to be a latter style long rod setup in 86 cases

[thumpers4ever]

Originally posted by fearlessfred
but far as everthing else it has to be a latter style long rod setup in 86 cases

that what I think. just trying to find out what I all have and whats been done. another thing is the cylinder is double sleeved. when I took the jug off I noticed it had a sleeve inside a sleeve, is this a normal way of resleeving a cylinder?

[fearlessfred]

Originally posted by thumpers4ever
that what I think. just trying to find out what I all have and whats been done. another thing is the cylinder is double sleeved. when I took the jug off I noticed it had a sleeve inside a sleeve, is this a normal way of resleeving a cylinder?
show us a pic of that

[muddymess]

definitely an 87-89 wiseco

[thumpers4ever]

here is a pic of the double sleeve cylinder. can anyone tell me the size of this piston?

[methyman]

I have seen that before on a Banshee cylinder. Instead of resleeving the cylinder they put a smaller sleeve inside the stock sleeve. You can still use that cylinder or resleeve it back to stock or get another cylinder. Its up to you!

[2-330s]

i have seen that before as well.usually they were sleeved down to make it a 200 cylinder for racing. measure the size of the piston to get a displacement

[thumpers4ever]

I don't have a mic but I measured piston what looks to be a hair under 2 5/8" so its a std bore or just over. I'll have to borrow a guage to find the actual bore size. after I clean up the cylinder I will see if I can just do a hone.

[atv fan 28]

Possibly a Selvys cylinder?:confused:

[Rich250RRacer]

Originally posted by atv fan 28
Possibly a Selvys cylinder?:confused:

This is nothing rare, in fact it's quite common. A few of the sleeve manufacturers make sleeves that are somewhat thin and do not allow for the original sleeve to be removed. From personal experience, cylinders with this type of sleeve tend to run very hot.

[Pumashine]

Originally posted by thumpers4ever
here is a pic of the double sleeve cylinder. can anyone tell me the size of this piston?

The piston size is stamped in the middle of the piston top. You are only showing the outside. The numbers that make a difference are the ones in the miidle on top of the piston. Tell us those numbers and we will give exact size and year!

[oachs83]

Originally posted by Pumashine
The piston size is stamped in the middle of the piston top. You are only showing the outside. The numbers that make a difference are the ones in the miidle on top of the piston. Tell us those numbers and we will give exact size and year!

Exactly, you will have a 9 digit number in the middle of the piston. That is just a casting number you shown that not even Wiseco can decode the size and year for you. Grab a wire brush or a wire wheel on a bench grinder and the numbers will appear like magic. probably a number like 562m06600 etc.

[bulldog diesel]

what if the numbers are gone?

[Pumashine]

Originally posted by bulldog diesel
what if the numbers are gone?

Take a pic and post for pin height and year ID. Measure the diameter of the piston at the level of the wrist pin. And you will have to measure the pin height to know if its 85-86 or 87-89