2002 CR250 set-up

[dmunro63]

I have spent countless hours trying to set-up my 02 CR250 and have finally come up with a jeeting setting that is acceptable but not perfect.

The power is incredible and smooth but blipping the throttle right of the very bottom (1/16th-1/8) is not as crisp as any of the 2002 model 2 strokes I have ridden. The rest of throttle range is perfect.

After a lot of trial and error and countless hours reading the forums on this excellent site I have come up with the following.

I ride motocross at sea level at approx 70 deg F. with stock reeds and FMF shorty silencer.

400 main
6BEY30-75 needle 2nd clip
30 pilot
Air screw 2 turns out
S8 Yamaha needle nozzle
Slide filed 0.75mm to make it a 5.0

I have tried the 76 needle and it is a little to lean with the S8 needle nozzle mod.

I dont no if the Mikuni carb is the problem and a Keihin would be better suited to this engine.

Also what silencer to do you guys prefer. The FMF shorty or the Pro Circuit R304 shorty? I run the FMF shorty with the stock pipe and I am not that happy with the silencer perfomance. I believe Honda makes great stock pipes and thats why I have stuck with the OEM version.

Which rear sprocket 49T or 50T? I am thinking of running a 50T!

 

[02'Cr Rider]

I too have been fighting the jetting on my 02 cr250.This my setup.

Head milled .010
v-force valve on low setting
380 main jet
27.5 pilot
6BEY30-76 needle on top
S-9 nozzle(have S-8 but like jetting where its at).
air screw 2 1/4 turns out.
running 50T rear sprocket
pro circuit pipe w/ FMF turbine coreII silencer
Motul 800 2T mixed @32:1

I have to run race gas.Tired pump gas but it just knocks.This bike pulls hard off bottom,strong mid,good top end,and Instant throttle response.My friend says his 02 yz250 doesn't run that powerful.Once you find the jetting,it works great. :thumb:

 

[dmunro63]

02 cr rider

Thanks for your opinion!

I run Motul 800@32:1 too but with 98 octane unleaded.

I find that the 380 main leaves the top end a little flat in my conditions.
Quite a number of people have been complaining that the top end is lacking and has no over rev but I find the 400 main the cure.

I will try the 27 pilot as well as the 50T rear.

Thanks :thumb:

 

[02'Cr Rider]

I forgot your running stock pipe.I found that the 400 main does make wonders for top end and the stock jetting does run flat on top,I do agree with you their.I bought a 50 T sprocket off ebay,check it out.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=1866580665

;)

 

[Bruster]

I am in and ride around the san diego area, sea level to 1,000'.
Here is what I have found to work in my conditions.....
Main = 400
Pilot = 27.5
Needle = 6BEY30-76 second clip
Nozzle = S8
Air Screw = 2 out
Slide = cut 2mm
Gas = pump 91 octane Mobil 1 mx2t
I have the pro circuit R304 shorty and it did hit well off of the bottom end but the fallout on the top end was too much of a sacrifice. If you want bottom end the R304 will work well.
I am now back to the stock pipe and silencer for the track I am currently riding.
Of all the jetting changes I have tried, cutting the slide made the biggest improvement. It made a large improvement in the off idle lag that the bike suffers from and also added a nice hit in the mid range. I found myself not having to use the clutch constantly coming out of corners. A nice plus.
All in all I am very happy with the bike. I have just learned a lot about jetting being the owner of a 02. I consider it a learning experience and not a problem :thumb: .

 

[jho410]

Hmmm ... just read an article in Dirt Rider where Eric Crippa from American Honda recommends the following:

> 400 main
> H272 needle in second position
> stock slide
> 32.5 pilot jet
> AS at 1.5 turns
> -8 spark plug

Anybody tried this? I am not able to find that needle either ... any advice?

PS ... I recommend a FMF Fatty for your 02 CR250. There is a fairly substantial gain in the mid (and overrev) compared to stock.

 

[02'Cr Rider]

jho410, heres some info on H2-72 needle.It opitonal for 2001 cr250.

http://servicehonda.com/HARD PARTS/OFF ROAD/CR250 2000-2001/carburetor_o_p__kit_(2).htm

 

[bedell99]

This must be the absolute hardest bike to jet. I live up in Vail Colorado and finally got the jetting right for there. The bike is totally stock engine wise. I mostle ride at approximetely 5500. Ok here it goes:

> 340-350 main
> bey76 needle in first clip
> stock slide
> 30 pilot jet
> AS at 1.75 turns
> -8 spark plug

Bike ran good, but here's my dilemma: I just returned to drove back to New York to race the KROC and some local race back here. I went to stock settings and tested at a track in Pennsylvania.(Jack Frost to be exact-1000ft) The bike ran so bad, I didn't even want to ride. I went back to 30 pilot, bey76 2nd clip, 380 main. Ran much better on saturday and Sunday in New Jersey and Long Island, but still was running fat on the very bottom. It actually runs faster at 5500. Thank God I'm going dring home tomorrow.

Erik