86 250r bore size?

[tp250ratc]

when i bought me r i didnt know much about it except a decent ebay description and photo. now about a year later i decided to freshen the top end. when i pulled it apart it had an oversize bore much to my surprize. the piston was a wiseco stuffed into a 71.something mm. bore. stock bore being a 66 mm. i believe. i wondered whats up here ? the local honda shop bored and honed it and got me another wiseco piston through la sleeve. the bore size is now a 72mm. this r rips pretty good to say the least. does this setup
make it a 300 cc kit ?



86 honda 250r atc
86 suzuki lt250r quadracer

[monster 84r]

no, there isnt a performance increase from boring it out, it jsut fre up the motor. any power increase would be too small to feel, a true 300 kit doesnt just open up the cylendar walls.

[Hornetpowerspor]

when i bought me r i didnt know much about it except a decent ebay description and photo. now about a year later i decided to freshen the top end. when i pulled it apart it had an oversize bore much to my surprize. the piston was a wiseco stuffed into a 71.something mm. bore. stock bore being a 66 mm. i believe. i wondered whats up here ? the local honda shop bored and honed it and got me another wiseco piston through la sleeve. the bore size is now a 72mm. this r rips pretty good to say the least. does this setup
make it a 300 cc kit ?



86 honda 250r atc
86 suzuki lt250r quadracer

Yes you have what they call a 295cc kit. You will notice a great increase in torque and HP. To figure out your engine displacement on a single cyl motor, use the following formula.
Bore x bore x stroke x .0031416 diveded by 4. Using this formula, You will then see what your engine displacement is. Hope this answers everything for ya

[monster 84r]

nvm i was wrong then, i didnt read his post clearly. sorry.

[TeamGeek6]

Depends on what piston was installed also. If it has a higher dome, the compression will be higher.

[tp250ratc]

a 295cc kit, thats pretty cool, i'll consider that a bonus to have that in the r as the trike seems to run real good set up this way. the wiseco piston is a standard dome and the head is stock too so no big compression difference is noticed.

[OldSchoolin86]

Depends on what piston was installed also. If it has a higher dome, the compression will be higher.

You must be thinking of a 4-stroke, you don't get domed pistons for 2-strokes.