Is there any differnce in the 4 years that thy made the 250R quad?

I know the 86 was a short rod & then they went to a long rod.
I believe they also added a bridge to the exhaust port.
That's all I can think of off the top of my head.

The 88 and 89's came with a shorter swingarm as well. There are a bunch of little differences from year to year, but everything is pretty much interchangeable from year to year.

Also,they made the 86 models both as ATC (3wheeler) and TRX (4 wheeler) but for some reason,the ATC has a higher output motor in the 86 model. So if you can get an 86 3 wheeler engine,you get more hp than the quad version- go figure !!

So it doesnt really matter what year I get? There pretty much the same?

go here
www.macdizzy.com/trx_specs.htm

Biggest difference was '88 and '89 had aluminum swingarms that were one inch shorter. Gearing was different on the '86's, other than that, pretty minor changes.

Differences between the years;

88' and 89' had 1" shorter swingarms than the 86, 87 AND the swingarms are made of aluminum (silver). However the A-arms are set forward 1". A-arms painted silver also.

86' and 87' 1" lomger swingarms (steel), and gold colored along with gold colored a-arms.

86' no bridged intake, and thicker sleeve.

87-89 bridged intake, and thicker cylinders (aluminum part).

Different plastics on the 88, 89. The headlight is in the hood also.

Footpegs differ from year to year.

Improved clutch on 89, maybe 88 also.

Slightly different frame geometry between the 86, 87's and the 88' 89's.

Rear grab bars different on the 86/87's compared to the 88/89's.

Transmission gearing different between the 86's and the 88/89's.
Not sure about the 87' trannys.

Front sprocket on all models; 13 tooth.
Rear sprocket on 86/87; 39 tooth.
Rear sprocket on 88/89; 38 tooth.

As far as one type of motor putting out more H.P. than another, I don't know if this is true or not.

When I tore my girfriends motor apart (first time since assembled from the factory) it was stamped with an "85", meaning it had the cylinder from an 85 atc. Mind you, this was assembled at the factory this way. It still had the original piston, rings, etc, still on the stock bore.

So basically, Honda used various year top-ends from the 85/86 atc's with the bottom ends from atc's/TRX's.

There are probably a few more differences, one being the short rod on the 86, but This is all I can think of off of the top of my head. [img]i/expressions/face-icon-small-wink.gif[/img]

Along with the 86 having the shorter rod, the wrist pin location on the piston is also lower.
All TRX250Rs have same bore/stroke, approximately same horsepower.
Same weight.
Same wheelbase.
Difference in mounting hardware for seats, but all plastic is interchangeable from year to year if you accomadate the hardware.
The 88-89 have a slightly higher compression ratio, from 7.1:1 to 7.6:1.
All are 6 speeds with manual clutch, who needs reverse?
All are kick-started.
If you want to really learn about the R, check out
http://pub20.ezboard.com/bhondatrx250r
Site is dedicated to the R and more info available than you will ever need.