I have a 1986 TRX250R and it is need of a new cylinder due to the exhaust bridge . I have been told that the best set up is a 86 bottom and an 88 top . The cost difference between the 86 and the 88 is quite a bit as the 88 is cheaper . I have been told that this will improve the compression useing the 88 cylinder but i do need to use an 86 piston with the 86 crank. Anyone use this set up ? If so how is it ?

 

The only difference between the 2 cyclinders is the exhaust bridge on the 88 and not one on the 86. The compression is the same, because that is determind by the head. Some people like the 86 lower end because 5th and 6th gers are just a little taller than the 88 lower end, 1 to 4 are the same in both. Which every crank that you are running is the year piston that you mush use, because of the pin location. But, if you have a 88 crank the pistons only go to 8th over. But, if you use a spacer plate, you can use the 86 piston and then you can go to 14th over on the piston. Many people do and don't like the spacer plates, it did work for us OK when we used it.

 

well actually, both have exhaust bridges. the 86 does not however have intake bridges, which the 88 does have. To bump compression you'll have to use an 85 or 86 ATC head gasket (CR works too but they leak often). The 88 cyl won't give you any more compression on its own

 

Thanks for the info . My 86 cylinder is toasted and i need a new cylinder to run this year and am already going to miss London Ky . Im haveing trouble finding a new one and wanted to make sure any year would work with my 86 bottom which i just reworked before the last race last year . Wish me luck and i hope to see you yet this year !

 

www.ebay.com

This place ALWAYS has cylinders for sale. Most are for 86 model TRX's.

Good luck![img]i/expressions/face-icon-small-wink.gif[/img]

 

I have an 87 cylinder and head thats .40 over... 110 shipped to your door.......

 

I also have an 86 top end, polished to like chrome finish, mild porting, piston, everything you need, bolt on and go. E-mail me at rhino99@hotmail.com if you are interested. I need to get it sold!

 

Rhino give me your email and ill contact you . Here is my email addy bowling@cnz.com you can also reach me on my web site www.bowlingracing.8k.com .

 

Sorry i seen addy after i wrote but i would like your addy on the 87 cylinder Sandgod .

 

Make sure your piston has the small holes in line with the bridge. They are for extra lube on the bridge.

Also on my old 86 250R I took some emery cloth & sanded the bridge till I could just see light between a straight edge & the bridge. I didn't have any more probs with this area after I did this.