XR250 porting, cams,277kit,any engine mods

[kevinfries]

Ive got a 2004 xr250, and I want to get some more power out of it. I have done gordons mods, except most of the time leave the baffle in, I dont like being loud. But my question is what should I get for my bike. I want to get a 280 kit, does eric gorr do boring on xr250's? I also want to get it ported, and would you reccomend any valve upgrades? I was thinking of a cam, I heard the hot cams stage1 cam is a good cam. Do you guys think the 280 kit, hot cams stage 1 cam, a porting job, and valve job is a good investment? Thanks, Kevin.

 

[Ol'89r]

I want to get a 280 kit, does eric gorr do boring on xr250's? I also want to get it ported, and would you reccomend any valve upgrades? I was thinking of a cam, I heard the hot cams stage1 cam is a good cam. Do you guys think the 280 kit, hot cams stage 1 cam, a porting job, and valve job is a good investment? Thanks, Kevin.

Kevin.

All good choices. Check on Eric Gorr's link on the left of the page and contact him directly. In my own experience, the ports are pretty good in these engines and only require a little clean-up.

<------------------------------------------------------------ :cool:

 

[kevinfries]

Will do, thanks. Only reason I came here is on his site it says come here before contacting him because he gets a lot of emails. But I will, thanks. Any other opinions? Anything else that could be done that isnt expensive? How much do you think this will cost, 277 kit, boring/honing, cam, and ports?

 

[kevinfries]

Wow, I just looked up the hotcam stage 1 cam, its $160, I cant afford that. My budget will be around $300-350. The piston is around $140, boring and honing from eric gorr is $50. Is what below what im looking for for porting? That's from eric gorr's site. So $140 for the piston, $50 to bore it, and $175 for porting. Thats around $365, does that seem right? What would you guys reccomend, porting or the cam?


CYLINDER HEAD PORTING $175
Includes all the same services as the head tune-up plus the valves and ports are decarbonned, the ports are textured for the optimum fluid dynamics, matched between port sets, and the valve seat is blended to the port. Some models get special valve-grinding to improve flow. All valves are lapped to the seats for proper sealing. Springs are checked for free length and tension. Aftermarket springs are installed for no extra labor charge.

 

[highmileage]

Kevin,

One of the areas that I have heard to cause some issues is the intake side. The intake boot has some problems where it transitions into the top end and doesn't always align very well. This area should not be polished smooth, however having edges sticking out just deflects intake flow. I found that as much as an 1/8 inch inside the inner perimeter of the intake boot that needed to be removed to clean it up and maximize the transition.

The stock carb/box/intake doesn't flow very well so removing the snorkle, proper jetting, and cleaning up the intake transition is about as good as it gets, unless you go full on (black diamond valves with a 3 angle grind and transitioning the shoulders with an aftermarket carb). Also a Uni filter with a high flow cage is dang near a must. Rejet as appropriate.

The exhaust side can use a bit of work, but is generally pretty good with just some smoothing of casting marks, etc. The exhaust baffle should be removed and the welds at the header openings should be examined. These welds should be smooth and not block any exhaust gas flow. Some headers are better than others, but all can probably use at least some minor attention with a dremel to smooth the welds out and maximize the intended inner header diameter.

I think for the money that the extra CC's is probably your best buy, however just the cam and some minor head work will also noticeably impact the bike.

The best money spent is kinda subjective as you don't say exactly what you are looking for in a planned improvement.

 

[kevinfries]

So do you think the cam is more worth it? I like torque, and it says the cam gives mid to upper, but will the bike still have more torque because of the 277 kit?

 

[Rich Rohrich]

, but will the bike still have more torque because of the 277 kit?

Yes, the big bore will increase the torque and move the torque peak down about 500 -800 rpm lower. The big bore and a good pipe like the Thunder Alley slip on ($250) will make a huge difference in low to mid torque and rideability. Like 89r said, the head is very good from Honda so porting is one of the last areas you'll need to look. Just keep in mind if you go to a big bore setup and increase the compression ratio you'll need to run better fuel than pump premium unless you also add the Hot Cam or an HRC spec cam. The stock cam closes the intake valve very early, which is great for low-mid torque but it also makes it sensitive to increases in compression ratio.

If you are strapped for cash the best bang for the buck is a big bore with the standard compression ratio and the stock pipe with a Baja Designs exhaust baffle ($99). You'll get a really nice torque increase and still keep the bike under 96 db.