Bigger Carb and Ported Heads

[cobia182000]

Please give some advice. What kind of gains can be expected from a port job and say an xr200 carb upgrade to a stock 250ex? Is it worth it. Would a full pipe be mandatory at this point. I dont see much feed back from guys that have done the carb upgrade.

Would the combination above greatly benefit from a higher compression piston?

With strictly performance in mind and keeping it to the top end of the engine. What is truley the best combination to maximize the power potential a 250ex has to offer? Would it be the combination above.

I don't mean to sound repetative. I did read the performance thread but still a little unclear. Thanks for your help.

[ryanh250ex]

I replied to your email, but this post gives me a little more info to work with.

The 22mm carb that the 250 comes with is too small. I never went to the swap, I just made the discovery that bigger carbs will work.

The big carb , let alone headwork is relatively uncharted territory. I never got around to doing either. I sold my bike at the end of last summer. But, knowing what I know, there is alot of room for improvement. The 250 is a relatively low tech motor. Yes, get a full exhaust.

For that reason above, yes, a hi-comp piston would also help alot. Stock IIRC is 9:1? I don't feel it is necessary to go up, although if you have the money, go for it.


The 250 motor is in such a state of tune that you could do basically anything to it to improve airflow in and out and you will see gains. I always tried to do things with a budget in mind, and with that said, I'd leave the piston stock, but I'd go with the biggest carb you're willing to work for , and port the head (see my email, I do porting on the side), slap a full exhaust of your choice, tune it, and let 'er rip. You'll have a bike that moves, for not alot of money and hassle spent, plus you can burn 87 pump gas all day long.



Originally posted by cobia182000
Please give some advice. What kind of gains can be expected from a port job and say an xr200 carb upgrade to a stock 250ex? Is it worth it. Would a full pipe be mandatory at this point. I dont see much feed back from guys that have done the carb upgrade.

Would the combination above greatly benefit from a higher compression piston?

With strictly performance in mind and keeping it to the top end of the engine. What is truley the best combination to maximize the power potential a 250ex has to offer? Would it be the combination above.

I don't mean to sound repetative. I did read the performance thread but still a little unclear. Thanks for your help.