piston size

[woodsracer144]

hey i have a lrd cyl with a piston with a 69.00 mm piston... the number is like this
3622I

203M06900
then a down arrow

I was going to put this on a ATC bottom end i have with the hot rods crack i had in my trx one but i found a crack in the piston and i would like to replace it if i could... or find a stock bore 86

[Langbolt]

It's a WISECO piston......but NOT for a 250R.

They start with 526 or 562 ('86 style or '87-89 style)

I checked to see if it was a Yamaha YZ250 piston but that part number is 234 or 542

???????

Geez! A search option on:

http://www.pistons-online.com/motorcycle1.asp?br=Yamaha&st=39&end=46

would sure help!

:devil:

[woodsracer144]

well dang this is weird... im gonna have to check the number again... im positive thats the one though..

[86 Quad R]

if/when you do varify the number call the link posted or call wiseco direct. either should be able to tell you exactly what piston you have/need. :cool:

[woodsracer144]

man im on crack! its 526M09600 niy o found a crack on my cylinder skkirt as well and its pissin me off so now i have to resleeve it! damb it anyway!

any body have a good sleeve kit to use?

[86 Quad R]

does the cylinder have a good aftermarket porting? if so, your best bet is to get a replacement sleeve from la sleeve and have a reputable builder install it. this will put you back at oem bore tho. but if the cylinder is strong in power you'll be fine. :cool:

[woodsracer144]

yes, it is ported by LRD and has a O-ring head gasket in it as well. im getting it resleeve but dont know if i sould go with a 310 or what...

[86 Quad R]

personally i'd go back to oem bore. there is a "thick" oem bore sleeve that be installed that will allow you to bore as many as 22-24 overbores.

[woodsracer144]

could you post a link to the "thick" one... i want to get as cheap of one as i can with a piston... if they come with it...

[86 Quad R]

you'll either have to contact la sleeve or an engine builder for the sleeve and i do not think the piston will be coming with it. more than likely it'll need to be purchased seperately.

[Honda5]

a new sleeve is about $100 and then the price to put it in. I think I have 1 new sleeve in my shop somewhere. but it may be cheaper to find a cyl and piston from someone on here that is ready to bolt on.

[86 Quad R]

Originally posted by Honda5
a new sleeve is about $100 and then the price to put it in. I think I have 1 new sleeve in my shop somewhere. but it may be cheaper to find a cyl and piston from someone on here that is ready to bolt on.

you may opt to do that depending on how partial you are to the power of the current porting...... resleeving is going to cost ya a nickle or twelve, on top of that is the cost of piston ect.

[woodsracer144]

im friends with a guy and he cuts me good deals... 35 bucks gets the old one out and the new one in... any bore jub is 20 bucks...

[86 Quad R]

if you are going to resleeve then i'd consider recording the port arrangement in there as it is now. it sure would make it easier to duplicate later. :cool:

[woodsracer144]

what do you mean by "i'd consider recording the port arrangement in there as it is now. it sure would make it easier to duplicate later. "

[86 Quad R]

in an effort to get the numbers back into the port timing when the new sleeve is installed. a port mapping can be done or the port numbers can be degree's in and recorded or a combination of the two. you should problably contact a porting export of your choice and see what his/her preferred method is.

[woodsracer144]

i wish neil or rustyatv would chime in on this...