Motor/Tranny info needed.

[busted]

Hi all, I am looking to see if anyone can point me in the right direction for some info. I just bought an 86 250r that I am going to go through the bottom end of. I am trying to find all the info out I can about the different year motors. I have been riding R's for quite a while but have never gone through the bottom end of one. Since I am gonna be in there I might as well replace a few things.

So what I am looking for is any info I can get my hands on about the difference in the gears. (I have always heard the gearing in an 88-89 was better then an 86). Also I would like to find some info about the crank and rod. IE long rod vs short and which years they came from.

Also if anyone has a suggestion of a setup that works well for them that would be great also. I mainly ride dunes, with some trails if that helps at all.

I hope I have not made myself sound stupid in here but thanks in advance for any info provided.

[Tom TRX250R]

The 88-89 transmission is preferred due to lower 5th and 6th gear which the motor can pull easier unless heavily modded. On the other hand, Beerock for example, opted for the 86 gears to provide more top end. You have to have a well built motor to pull 6th in the dunes with an 86 though compared to the lower geared 88-89.

The long rod crank was produced in the 87-89 R's while the short rod was made 85-86. When I replaced my 86 crank I swapped to an 89 for several reasons. 1. It provides more crankcase volume (when used with 86 piston) which produced more low end 2. It provides longer piston life because there is not such a drastic angle on the cylinder skirt to wear out the piston sooner.

It is a good thing to learn the knowledge of rebuilding your lower end. Just a tip, buy a flywheel puller, its only around $12. Also, when your rebuilding the lower end replace anything questionable including clutch, clutch basket, and any bearings/seals. Good luck and let me know if you have any questions, I live about 15 minutes from you so could help you if you have any questions, just buy a case a beer! I have rebuilt 4 250R's lower ends and know them like the back of my hand now:p