250r moter?

[mxmike17]

How can I find out what year moter I got?

[wilkin250r]

Are you sure your motor is all original from the same year? It's certainly possible to have an 86 bottom end, and an 88 top end. Or vice-versa. It's also possible to have an 86 bottom and top end, but have an 89 crank and piston. Heck, it's possible to have an 86 bottom end, 87 crank, and 89 top end with an 88 cylinder head.

[mxmike17]

Thats the problem I have know idea what I have,lol.

Im trying to get it all figured out now so when I order a new top end I will know what to get.

The moter runs strong but I havent got the slightes clue what all work it had dune to it. I kinda want to find out what botem end I got (im pretty shure that part is stock) and start fresh up top with an ESR kit. That way I know what I got.

[asdf450r]

I think i remember reading somewhere that the year is stamped on the bottom outside part of the sleeve (ie 86,87,88,89). That would only be the top end though.

[seth400]

87-89 rods are longer than the 85/86 rods
85/86 piston is a longer piston than the others
if it has a spacer plate then it most likely is an 87-89 crank with an 86 style piston.
86 cylinder has no intake bridge,
87-89's do

there is also a plate on the side of the clyinder. you can tell what year it is by that i believe, there may be one on the bottom end somewhere too
hope this helps

[wilkin250r]

Somebody correct me if I'm wrong, but I believe any cylinder head will fit any cylinder, and any cylinder will fit any bottom end. There is a slight difference in the cylinders (as pointed out already, the 86 doesn't have an intake bridge, the 87-89 do) but the actual performance doesn't differ greatly. So knowing the particular top end will satisfy your curiosity, but I don't think the information is particularly useful, since there is very little difference between the different years.

[1988R]

The most important thing to know is which rod you have (long-short). If you have a long rad and use an 86' piston you will need a spacer plate. All cylinders will work on all bottom ends. As far as identifying the year of each individual pieces I don't think it can be done. I've never heard of the year being stamped on the cylinder The bottom end can be identified by the numbers on the leftside center case,BUT can't always go by that because the break if the chain comes off and jams up. then people will get any year center case to fix it

[mxmike17]

Thanks guys this is all usefull info.

I think in my situation from what I have read it would be best to take it down and see exactly what style crank I have and then build up from there?


I also am trying to learn what carbs are runnig best with these bikes. This one came with a kein. I dont know the size yet. I plan to take it to the local honda shop and see if the can tell me. It needs a new float bowl gasket and some jets to play with.
Also is kein the same as pwk? I have seen both names used in the forums and wanted to clarify that.

[beak7707]

pwk is a carb kehin makes, so yes same thing. If you take your cylinder off there should be a year stamped on the back side of the sleeve, that sticks out the bottom of the cylinder. Also if it is an 87 top or bottom end it will be painted grey, if the cylinder and bottom end is black 85-86. Black bottom end with bare finish clinder 88-89. You should be able to tell if you have a long or short rod by the piston you are running, the 86 piston looks diferent from 87-89.

[mxmike17]

Thanks, Its got black bottem and bare top and does not apear to have any spacers. I suspect 88/89? I will still check the crank when it is time for a rebuild. Im just trying to prepare myself.