2004 cr250 powerband

[jgid723]

I just purchased a 2004 Honda cr250. It seems to have good power in low rpm range, but no hit in mid to high rpm's. Feels like it is bogging down. Could this be related to the powervalve adjustment? The bottom of the engine is an 04 with cylinder, cylinder head and powervalves from an 02 model. The servo motor is also an 04 and I noticed the 02 and 04 have different part numbers for the servo motor. Would this also cause a problem?

 

[Reesknight]

The '02 model was know for an anemic engine(down on power). This was addressed on the '03 model with a change in porting, different pipe and powervalve, and different intake characteristics such as an 8 pedal reed valve. I don't believe this completely resolved the complaints but did help from what I've read. Even the '03 had a smooth power band with not much of a hit tho. I don't know what changes they made with the '04.

 

[+30]

04

I dont own one but I heard the 04 has even less bottom than the 03, but your 04 should have a very nice strong mid to top. Something must be up. Not sure if the 02 pv setup would work for 04, there is a good thread on adj the pv on this site under 04 rc powervalve adjustment and also
http://www.he-ja.nl/hejatips.brits.htm

 

[jgid723]

I adjusted the powervalves per the instructions but I still get the same results. Could it be running too rich? Although I have ran it for probably 6 hours total over 2 days without fouling a single plug. What would you suggest to check next. Thanks.

 

[xprojectstevex]

If anything fuel related I would say it's too lean on the mid to high throttle range.

 

[crazyrydermx]

You may need a richer main jet. The main jet is used from about 1/2 throttle to full throttle. The main jet is the main fuel supply at these amounts. I would do a plug chop to figure that out...It could also be the jet needle. This is used from about 1/4 to 3/4 throttle...so if that's where you are experiencing the problem, this is most likely it.
Also, is it a stock pipe? There are a few pipes out there that make the lower hit harder but what you gain in one aspect, you lose in another.

 

[jgid723]

It has the stock pipe and silencer on it. What do you mean by plug chop?

Thanks for the info.

 

[jgid723]

Any more suggestions?

 

[Dieselhed]

I have an '04 CR250 and it doesn't have much in the low end department but the mid to top hit will rip your arms out of thier sockets. I would question the use of the '02 cylinder head and power valves. In '04 they went to the electronic PV. (And back to the mechanical one in '05) Don't use parts on the '04 unless they are made for the '04. Honda made alot of slight changes each year between '02 and the present. Do you have the service manual for the bike. If not, get one. It is worth the money and takes all the guess work out of working on this bike. I put on a Pro Circuit Platinum pipe and R 304 Shorty and Boyesen Rad Valve and this bike flat out rips. Keihin PWK coming soon. Good luck and let us know what happens.

 

[BSWIFT]

It sounds to me that you either have a non-functioning or improper functioning PV. The other option is the carb, clean it and check the size of your main jet and compare to the stock jet. Check your clip position.

 

[jgid723]

It seems the previous owner neglected to ever change his silencer packing. It looked like it had been saturated with oil at some point and left to sit over a one year period and had become as hard as a baseball bat. I replaced the packing and it runs like a champ now.