to my surprise my 87 lt 250 r that i had just rebuilt has actually turned out to be an 88....well, all is well except that the piston is not the same. even though it fits and runs somewhat ok, the 87 piston isnt ported the same nor has the same wrist pin height. i thought when i put it together and tried to start it. it didnt seem to have the compression that it should have..im fairly new to this stuff, so i just took it as a learning experince and went on.. it also was a bitch to jet.. but now im pulling it back apart to put the right piston in it, i hope the jetting works out a little better. and if it starts better it wont hurt my feelings..this isnt my first 250r so i know the starting trick, but it was still hard to start. i guess i should have looked into learning the correct year before i started but, i thought that the 87 to 92 years were the same, and i knew it had the power valve, so i didnt look much further. oh well...one question though, can anybody tell me where i should start out on jetting? its all stock other than 1 mm over bore and boysen power reeds. starting the jetting thing over again sucks..

 

What symptoms did you have? I bought mine as a 89, but when i ordered the piston, they just pulled the weisco number off the old one which was for a 87, it doesnt seem to have the compression it should. It runs good, doesnt seem to foul plugs, and is jetted pretty good.

Mark

 

Even though i know the trick to starting these things its still hard to start. jetting isnt where i really want it, but i cant seem to get it there.. mainly the compression is off, but the biggest thing is , is that they say the oiling holes arent in the piston that are needed, but i really didnt have a problem with oiling i didnt think. but when you wind it up real high it smokes pretty bad and im guessing thats part of the piston being the wrong one.. i dunno what about yours how does it do?

 

Ok, when its warm out like 50+ it will start on the first or second kick even after sitting a while, it really does not smoke at any point, but it kicks over kinda easy, but i havent ever kicked another one to know if its low or not, and everyone rants and raves about the power its supposed to have, especially with all the stuff that is done to mine, but the neighbors 400ex basically stock will give it a run for its money. I dont know, I really dont know, its starting to frustrate me.

Mark

 

when we hook up so i can give ya shock ill help ya bud.

 

Sounds great!!!!

Mark

 

87 vs. 88-92 engine differences

 

its the piston. same with mine it runs good but not how it should... ive had 3 others and this is by far the sickest any of them has ran.. i ordered the new stuff should be here tomorrow. i wi;ll let you know how it runs.. after the right piston is put in..

 

The only thing about my bike that throws that solution off is that i ordered and went to replace my reeds, and my reeds were WAY too small,which implies in my case that either i have a 87 engine or just the cyl.

Mark

 

look at that link above mark. if you have an 87 cylinder which you do. then u should have an 87 piston to math the port timing. now i got a problem i bought 88 head and was gonna put it on my 87 cylinder am i gonna have problems? depth of dome is diff and the diameter of dome looks to be different also on the link.....hmmm look as if im relisting an 88 head and an 86 head to find a 87. kicks himself for losing that cool head for 89 bux on ebay now.