250 ex mod help

[lifesun]

I have a few questions regarding some performance mods for the 250ex. Before I get a bunch of replies telling me to get a bigger machine….its for my wife, and she likes her auto-clutch!

OK, that’s out of the way. Here is my dilemma:
She wants more power; we have already piped and jetted it so I figured that we have two options.
1. Replace the stock cams with web cams or,
2. Get the powroll 250cc big bore kit with rocker arm.

Now obviously the cams are cheaper, and I would think that they would give enough to satisfy her, yet I hear that they are a bear to change. ( My service manual will be here tomorrow).
The big bore kit is obviously more expensive, but I hear that it’s easier to install and have heard good things about it except that you need to run race gas because of the high comp piston.

Can anyone give advice regarding this? The ease of installation doesn’t bother me too much with the web cams; I just want it to be worthwhile, do they give a noticeable gain? And I like the idea of the big bore kit, I just don’t want to be required to run 110 gas in it.

Any help would be greatly appreciated.
Thanks, James

[4TraxRider]

from my experience, just a cam doesn't do much for HP, it will bring an engine alive that has a high comp piston etc. Id say, go with the poweroll kit.

[WickedRider]

u have to run race gas w/ the powroll kit? that sucks.

[offroadfury]

Where did you get your service manual and how much was it? Did the pipe and jet kit help it out any? I bought one for my g/f and she really likes it but it lags a little on power and I was wondering if a pipe and jet kit is really worth it on this bike.

[lifesun]

So far you guys are leaning toward the Powroll kit. Does anyone have personal experience with this kit? I don't mind spending the money, I just want to be happy with the mod. I guess I will contact Powroll to see if indeed race gas is necessary. Any more input on this would be greatly appreciated.

I purchased the service manual directly from my Honda dealer for $50.

I forgot to mention that along with the pipe and jets, we added a K&N filter and 6 vents in the lid. It helped the machine out quite a bit on the low and mid range. We went with a FMF Megamax II, $170 from RockyMountain, and we are running a 104 Dynojet at about 800 ft elevation. My wifes friend also has a 250ex with a Graydon Proline full exhaust system with K&N and jets, and in a drag race they are pretty much the same, so I really don't think that there is an advantage to a more expensive full system on this machine. When our 250ex was stock, the piped machine would get about 4 lengths in a drag. I would definitely recommend a pipe and jet kit, it an easy mod with good results.

Any more input about this big bore kit?
Thanks again

[lifesun]

I called Powroll today and there is no need for Race gas when using the big bore kit. They recommend premium pump gas, but have also safely tested it with regular. Looks like this is the way I will go for an upgrade.

Thanks for the help guys,

[cals400ex]

i bet the cam will make you loose low end power but there will be a nice gain on top end and at high rpm's. i doubt you will notice much power gain with just a high compression piston. however, if you just bore the cylinder out and buy a high compression piston and put a cam in too, that should really wake the bike up. i don't know much about the 250ex, but in the 400ex's the cam is easier to change than the piston. good luck

[CG's]

I don't think you would need to run race gas because 10.8:1 isn't extremely high for race gas. Like said above I would run premium though. If you did the powroll I would forget the cam maybe? Your bottom end may be weaker. If you did the powroll I would carv out or cut the very end of the snorkel off so the powroll kit can get much more air. The snorkel itself make a difference on a stock 250. I couldn't imagine what the difference would be like when there 19 more cc's trying to pull air through. Anyway!

[Cody_300ex]

My friend has a 250ex with a big gun pipe a web cam bored .20 over with a 10:8:1 piston and that thing will haul *** for a 250ex. hes fixin to bore it .80 and get custom 11:1 piston made for it.