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Lookin for a little more juice! Any help?

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Howdy fellas,

I have been a longtime 450 pilot but just acquired a 2005 CRF250. I was pleasantly surprised with the power but could always use more right?

Just rebuilt the whole motor with hot rods crank, and a JE high comp piston. it was said to have some lightened rocker arms.

Stock exhaust and stock jetting.

I would love to have a little more hit and top end.

Any must do mods? I have noticed a pesky bog also, when really crackin the throttle or a g out type situation.

I was reading that a new accelerator pump cover might do the trick?

Thanks in advance!!!

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With the bog, you can also change the leak jet in the float bowl of the carb. Along with the AP mod, it will pretty much eliminate it all together. The 06 was the most notorious year for the bog with the less than desirable linkage set up on the accelerator pump. Not sure if the AP mod needs to be done on the 05 carb, I don't have a lot of experience with the 04/05 carb so maybe someone will chime in and clairify. The adjustable leak jet is what I've used to eliminate the bog on all the other years. Roughly $100 and it takes all the guess work out of it. The leak jet in the bowl makes a tremendous difference on bogging and they are a lot cheaper than the adjustable leak jet set up. It's just a little trial and error to get it right.

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The 04/05 have the same AP linkage set up as the 06, the bog on the 06 was just more noticible due to the larger carb.

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Ah thats some good information, I had stumbled on that accelerator pump mod, looks interesting.

How about pipes? Do they make that much of a difference? or are most simply aesthetics?

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Ah thats some good information, I had stumbled on that accelerator pump mod, looks interesting.

How about pipes? Do they make that much of a difference? or are most simply aesthetics?

They do make a difference in the power delivery. You're not going to pull a bunch of HP out of one. You'll get mixed answere's on what pipe works best for certain applications. They're all pretty decent but some come at a pretty good buck. The MRD is a real nice system and you could probably get a good deal on one from ebay. Even new, they're pretty reasonable.

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to cure the g out situation your going to have to experiment with raising the fuel level in the float bowl the pump mods help a bit .

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most of the people i know including me swear by yoshimura. good customer service too i know from experience. i never rode my bike with a stock pipe so i can't say about power delivery but my friend put the same system on his older crf250 and he said it hit a lot harder down low.

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I noticed with the FMF Ti megabomb system my kid has on his 08 is that he's not on the rev limiter nearly as much as he was with the stock pipes. That's music to my ears! The location of power delivery seemed to change with the megabomb system and he's able to pull the power that he's looking for lower in the RPM range. Since I don't ride it, that's just what I observed.

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