250r (long rod-vs-short rod)
#1
#4
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
You need to understand something.
All TRX250Rs in stock form have the same bore and stroke. All are 246cc.
The 86 had a shorter connecting rod than the other years, not a shorter stroke.
When they installed the longer rod in 87, they moved the wrist pin up higher in the piston to compensate.
All TRX250Rs in stock form have the same bore and stroke. All are 246cc.
The 86 had a shorter connecting rod than the other years, not a shorter stroke.
When they installed the longer rod in 87, they moved the wrist pin up higher in the piston to compensate.
#7
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
trapperB is exactly right again[img]i/expressions/face-icon-small-smile.gif[/img][img]i/expressions/face-icon-small-wink.gif[/img]
strokedbanshee- as trapperB said the 86 was the short rod model, but still had the same bore and stroke, and you wont really notice a diffrence between the two.
Do you mean put the long rod in the 86 motor, and short rod in the 97-89 motors? if so then yes all you will need to do is to use the same styler piston. Overall the rods are 5mm diffrent. the 86(short rod) had a style piston were the wrist pin was 5mm LOWER then the 87-89 pistons which were all the same. The 87-89 pistons wrist pin was 5mm higher than the 86 piston, because of the rod.
strokedbanshee- as trapperB said the 86 was the short rod model, but still had the same bore and stroke, and you wont really notice a diffrence between the two.
Can you do a conversion To other connecting rods?
Trending Topics
#9
![Default](https://atvconnection.com/forums/images/icons/icon1.gif)
The bore and stroke is the same, they just moved the wrist pin on the piston to compinsate. The reason they did is reliability. The short rod version wore the cylinder to much becuase it was pushing the piston to much. That is why the 86 bores are egg shaped really bad on a tear down.
You can do a long rod and 86 piston setup - this is what you could consider a LONG ROD or Stroked setup. It requires a base plate spacer and some porting. THey are pretty good racers, but not your daily racer.
You can do a long rod and 86 piston setup - this is what you could consider a LONG ROD or Stroked setup. It requires a base plate spacer and some porting. THey are pretty good racers, but not your daily racer.