porting? bridged exhaust or not?

[woodsracer144]

what are the pros and cons of a bridged exhaust? I was working on a Polanda build and they dont have a bridge.

does anyone remove the bridge in a 250r?

[Rich250RRacer]

I believe the bridge is required because of the width of the exhaust port. Without the bridge, your rings would decompress slightly and they would snag on the top and bottom of the exhaust port.

[woodsracer144]

that makes sense... haha where are the gaps on the rings located in the cylinder? i cant remember... like about 8 and 9 o'clock?

[wilkin250r]

I believe the gaps are more like 10 and 2 o'clock, on both sides of the exhaust port.

Or are they both sides of the intake? Odd, I can't remember which side they're on....

[SilverLake250R]

I think they are on the intake side, close to 4 and 8 o'clock. On the 87-89 with the bridged intake, they run right on the bridges.

[profab250R]

they are there for longevity, but if you are meticulous about your machine and do atleast rings every 40-50 hours the bridge wont matter much, Especially if you have chamfered ports. A lot of the aftermarket cylinders dont have a bridge. as well as the intake side on the 85-86 cylinders. the rings will decompress more towards the ring gaps than anywhere else and they do just fine on the early model cylinders. So dont let that scare you off.

[woodsracer144]

performance wise would you gain anything out of having on or not having one?

[morse250r]

if porting numbers and shape are good it can be done mines removed and a buddys i drill oiler holes in the piston so it lubes on each side of the exhaust port (stock oilers are in the center to lube that exhaust bridge. there is a gain but you have to use good oil and take percautions on reagular mantaince

[woodsracer144]

how big of a oiler hole did you drill? 1/8th?


another question i have is could a stock trans hold up a 330?

[morse250r]

i use the same size hole as whats existing ive heard some pistons now come without i have some pistons with the mod made but its smaller than an 1/8th

stock tranny will be fine
again how you take care of it i change my oil alot and use honda trx cr red bottle lube

im at 70+ hp on a 363 with a stock trans

i have blown out 2nd gear but with anything there will be breakage as you get bigger and this trans im speaking of was brand new from honda with about 5 years of run time