250R Long rod

[Tecate Karl]

So I'm new to this 250r long rod/short rod thing. So I am wondering what the real diffrence is and what are the pros and cons of each I'm getting ready to put a crank in a 85R and am wondering what would be the better choice thanks.

[dcreel]

My question is if you run a trx long rod motor with the spacer can you still use the atc250r head stay? Or is that why they sell the cool heads without the head stay?

[Tecate Karl]

well Doug good Question I'm really hopping someone jumps in hear and enlightens us.

[200xranger]

i used a long rod with an 86 piston and spacer plate and the motor mount for the head lined up and i too have an 85 atc. dont ask me how but i did no mods to it for it to bolt up. from what i read when i did mine it decreases the crank volume so the motor doesnt rev as quick and gives you more low end.

[cr480r]

a spacer and longrod increases the case volume

[bkm]

I have mixed feelings about the long rod. I have never ridden a long rod engine that impressed me. I like the quick hit and reving of the short rod engine. This is personal preference though and others might like a smooth power delivery. I like a light switch powerband.

Honda went to the long rod in '87 to improve low end torque on the TRX models with the extra weight of the fourth wheel.

My opinion is that the trike doesn't need to worry about the torque because of how light it is and if it was me and I had to rebuild a short rod engine it would go back as a short rod crank.

As far as the head stay I have heard some say it will and some say it will not work. I think that most that do not work are the stroker guys with thicker plates.

[NOS_350X]

The reason for going to the long rod was to decrease piston wear. It makes a less harsh rod angle on the piston.

There really isnt much performacne difference, (if any)

When going to a long rod and spacerplate, you increase crankcase volume, Its not that bad on a big engine, but on the small one s it really hurts high rpm's (the dyno's dont show a gain down low, jsut a loss up top) but because there is a loss the bottom feels stronger.

I personally like the short rods better. But performace wise my fastest engine is a long rod. Go figure.

As for the head stay, my recomendation is to not run one, i have see them crack, on several engines.