i am about to start on a project LT250R, the frame and suspension is a '91-92. but my question concerns the engine....i have both a '87 motor and a 88-92 motor that both need to be rebuilt and I can use either one. i know more mods are available for the 88-92( i.e. rad valve) i also know the only differences are the reed block and a slight difference in porting.
i will not be porting the cylinder or modifying the head this time, but it may get done in the future. which is the better engine to build and why?

 

I am also curious concerning this question. Looking at used quads now and curious which engine is the most reliable and "best" and for what reasons. Thanks -- Hollywood

 

I would use the 88+ motor. The 87 which I had was a huge improvement over the 85-86, and is about the same as the 88-92. The 88+ will give you far more options as far as upgrades and finding used replacement parts.

 

87 race rider is right.. you iwll not find half the parts u will for the 87 + years.. but the 87-90 are also diffrent than the 91-90... i really do not know what the diffrences from those... but a 88+is a good start....

 

the changes in the '91-92 were in the frame and suspension, not the motor. in '91 suzuki added more gussets to the frame and completely changed the rear shock linkage, swingarm, and relocated the airbox behind the rear shock... the result was the best rear suspension on any LT.

as far as i know the motor is the same from 88 to 92.... the '87 is the odd duck.

now to get technical.... the reed cage is one item that changed in 88, they used the same reed cages on both the LT500R and LT250R... it would be completely logical that the designers would not put the same reed cage on the 250 if it didn't even flow enough for the 500.

if i recall correctly, the main reason for the changes in porting after '87 on the LT500 was to make it easier to start.... i'm not sure that these are the same reasons for the changes on the 250.


also by logic(although not always true) the later models of 250's should have better flow, power and more potential if modified.

i think i just made my desision.

 

I thought the lt250 that were built after 88 had the power valve and that was the really only difference.IM not sure if its the 500 or 250 but the newer ones have more headbolts( 6 instead of 5). Even if you dont plan to port now you may later so use the motor that is the most upgradeable. I have an lt250 with anLRD pipe,k&N filter,porting, head work, etc. and basically evrything you can do to a 250 and still be a 250.IT is faster than most quads I come across. I havent seen a four stroke that can keep up, exept if the straight aways are long enough to where their taller gears and catch me.

 

The 87 LT250R has a power valve. It is the basically same motor as the 88+ but with slightly different sized reed cage, porting, and piston. I would still go with the 88+ because of parts and upgrades that are available, unless the 87 is in much better condition as far as cases and gears. Good luck....either motor should rip!

 

Half way thru 91 Suzuki changed the tranny in the 250. don't know way, but my machanic found out when we went to replace 2nd gear and a shifter fork. They asked for the motor serial number because after a certain number they changed the part numbers to the 92 model. Mine happen to be the newer version. Other than that the 88+ are the same. I know the 87 used a different piston and head gasket than the 88+. I tried to use a 87 head gasket and it kept over pressurizing the system and blowing antifreeze out of the overflow. Changed to the 91 head gasket and solved the problem.