86/87 TRX250R or 88/89TRX250R

[BIGKAHUNA]

What are the differences in the 86/87 TRX 250R and the 88/89 TRX250R? Are the motors the same? What about suspension? It seems I heard that one was favorable over the rest. I am thinking of building one of these so any input or opinions will be greatly appreciated.

[ATC crazy]

The '88-'89 are the most favorable ones and the best I think. I heard that they redid the engine to make it more reliable and powerful in the '88 & '89 models. The '88 also looks a lot better than the '86 and '87 models. If you do go with the '86-'87's, I'd replace the rear swingarm with an '89. It's stronger and easier to adjust the chain. I would go with the '88

[BIGKAHUNA]

ATC that is exactly the typo of info I am lookin for...thanks for sharing your advice.

[OldSchoolin86]

They have the same engine just different strokes and the 88-89 has an updated clutch link in it. They all have different porting and many say the 86 had the best. The chain adjust the same on all of them but the 86-87 has a stop bolt in the rear too. It's a small little thing, nothing to worry about. The 88-89 is the best looking. It has a different swingarm that replaced the need for the motor to pivoit bolt braket. The casting on the motor didn't even change, the bolt holes are still there just not used. The differences are very small between them besides looks. You can't go wrong with any of them. Just about everything will interchange. The only thing I would do if I got another 86-87 would be to put the 88-89 clutch link in it. Even that is a small deal if you can do minor work. There are lots of misunderstood rumors about the differences between them. You can always PM me if you have questions.

[freaksfix]

Like O.S. said the clutch link on the 86/87 likes to pull out, 88/89 swing arm is shorter like an inch shorter, 86/87 has a shorter stroke and a bigger bore so quicker rev. My 86R beat alot of 88/89's the 86/87 was a better motor and the 88/89 looked better cause the light being in the nose..

[OldSchoolin86]

They have the same bore. The rod length is different but the same stroke.

wouldent that make them have the same displacment??? the different size rod makes the stroke..thats why, to make a stroker 250R you need a spacer plate to compensate for the longer stroke. in order to have a longer stroke and still have the same displacement the bore has to be smaller..

[OldSchoolin86]

Bore and stroke are the same on all of them. The only difference is the deck hight. If you lengthen or shorten a rod it won't change the stroke. All it will do is change how high the piston goes. A "stroked" motor will have a shorter rod because the pin in the crank will be moved more to the outside. This will give you a longer stroke. All Honda did was change the deck hight, the top of the cylinder.

[freaksfix]

:oops: O.S. yer right dude sorry! opened my mounth before I looked into it....HAHA the one time your right and MRATC aint here to see it!!!! so what are you crossing to make the stroker motor? what 88/89 parts go into the 86/87 motor?

[OldSchoolin86]

Well you can't make a stroker swaping parts, what you make is a long rod motor. It's the 88-89 crank/rod & Piston in the 86-87 with the spacer plate. It gives you more crank volume.

[freaksfix]

Oooooooooo I was under the ass-umtion that you could make a stroker outta the two....listening ta too much BS from my drinking buddies instead of looking into it...

Not trying to be an trailprotrailprotrailprotrailprotrailpro here, just seeking to clear up some possible misconceptions....

A "stroker" motor is made when you change the length of the crank 'throw'. This causes the piston to move up and down a greater distance, thus increasing the stroke length and therefore increasing displacement. To increase crank throw, the crank must be ground with the rod journal off-center to the outside. In some engines, a longer rod is needed for the piston to clear the crank since the piston is traveling further down.

Are the 86/87 cranks different from the 88/89 cranks in stroke length?

[OldSchoolin86]

Right but don't forget if you stroke it and lenghten the rod you'll need a piston with the pin moved too so you don't ram it through the top of your motor.

[dogger]

O.S. I want ot clear up a little bite. the deck highs are the same on all the trx motor's they are not hight on the 88/89's the reason for teh longer rod is they moved the pin hole in the piston I think like .5mm the reson for this is to make the piston more stable and reduce teh wear on the skirt. the deck highs reman the same as does teh stroke but because teh wrist pin hole is moved they had to get a longer crank. this also is why 86/87 piston's are differnt from 88/89's. they are also some other differnces in the front supsension. not sure exzactly but I think it's the a-arm and the spindle. also there are some small gearing changes through the year's but it ain't realy much differnce there. all in all any year trx isa good one. the diffences are to small to nit pick over and you like something better on one then the other there is almost always a way to change them over.

[OldSchoolin86]

That makes sence. Sorry for the false info.