some questions

[250R_SV]

hey my friends I have a couple of questions maybe you can help me out:
-With a 70.00 piston what dome is recommended?
-When is it that you need a spacer in the reed?
-the spacer in the cylinder is only used when you have a long rod(88-89) and long piston (86) ?
Thanks

[1promodfan]

Originally posted by 250R_SV
hey my friends I have a couple of questions maybe you can help me out:
-With a 70.00 piston what dome is recommended?
-When is it that you need a spacer in the reed?
-the spacer in the cylinder is only used when you have a long rod(88-89) and long piston (86) ?
Thanks

Most guys use the reed spacer to take up the gap when using a CR250 stlye boot. Sometimes the carb. doesn't reach so a reed spacer can come in handy. There is a couple other uses, but thats another theory.

If you have a long rod crank and you're using a '86 cylinder/piston, thats where the spacer comes into play. The pin location is different on the piston which allows the stroke for the long rod......(not to be confused with a long rod motor)

[deathman53]

a 70mm piston, what is that 140 over? Talk about taking a cylinder to its last useful point, that sleeve has got to be really thin!!! You need a special head gasket, the bore is bigger than opening in gasket.

[Dave83]

More like .160 over---WOW!!!

[deathman53]

I didn't think they made a piston more than 140 over(69.5), or he's using a yz piston and 3mm spacer plate

[jcs003]

im pretty sure that is a big bore. isn't 70mm 265cc???

[Honda 250r 001]

Originally posted by jcs003
im pretty sure that is a big bore. isn't 70mm 265cc???

70mm = 295, he has a 310 big bore prolly.

[86 Quad R]

its the 72mm bore that makes a 295. a 70 would be a 277. :cool:

[250R_SV]

Yes the cylinder is in its last bore, its really thin. Its a suzuki piston, it makes it around 270cc. Its without spacer plate. Really nice pull. Lots of compression. Custom made gasket. Stock dome.