2003 Cr250 Jetting - Giving Up!!

[CR_Dave]

Let me start with the bike specs.

2003 CR250
About 700 feet above sea level (Western PA)
Temperature about 70-75 degrees (humidity has been high)
BR8EG Plug
VP-C12 Fuel (had detonation problems on pump gas)
DEP Pipe and SIlencer
VFORCE

30 Pilot
400 Main
#73 stock needle
S9 stock nozzle
2 turn out on Air Screw
Clip - 1st position from top.
stock slide

The low and mid-range on this bike is perfect right now. Crisp and clean. The bike has the power. But I need to grab the next gear when at full throttle in order to get the bike back to the mid-range because of cracking or popping when fully revved. The plug looked lean, so I went up to 410, 420, 430. The plug went from a lean to a bit richer look. But the problem at the top end still exists. I even went the other way on the mains, tried clip positions, and exverything else I clould think of.

Feeling I might have an air leak, I checked the crank seal, re-did the vforce installation, cleaned the carb. No luck.

Most of the Pro riders in the area seem to have given up on the jetting as well and went to a Kehin carb in place of the stock Mikuni TMX. I am about to that point as well.

Any suggestions as to what I should do. If it is a new carb, what and where should I get it.

I just want to be able to feel comfortable going down a long straight and into a jump without feeling like the bike is going to seize.

Thanks,

Dave

 

[pro2k]

I'm definitely no expert but my bike is running spot on. I bought a Tom Morgan jetting kit which consisted of a different needle and that's it. I also got a book on general recommendations for the the jetting. Basically for 68 degrees and sea level altitude the bike is set at the following: 420MJ, 30pj, 2 turns on the AS, 6BEY30-74 needle, #3 clip from top, stock slide, stock nozzle. Now, using the TMR correction factor chart I came up with the following for 800 feet and 75 degrees : 410 mj, 30pj, 2 1/4 turns AS. #3 clip pos on the 74 needle.

Give that a try and see if it is any better. Mine runs pretty damn good!

 

[pro2k]

Oh, those settings were for a stock bike with v-force reeds, running 91 octane gas with redline race oil mixed 48:1

 

[mx547]

if/when i get a new cr, i will also be ordering the keihin carb. i'm not going through that nightmare.

 

[john stu]

i will not buy another cr untill the carb isues are fixed i will buy another bike before i go though this again.

 

[murphy's law]

hey john, i'm right next door in R.I. and this is waht i'm running with my 02 CR 250. The bike finally runs clean from top to bottom. I wish it had a little more over rev but i guess you cant have everything.
370 main
6bey30-76 in the 2nd clip pos
30 pilot
S-8 nozzle
v-force reed
fmf fatty with titanium sil
vp C-12 mixed wtih motul 800 @ 32:1
How close is this to your setting for your 02

 

[CR_Dave]

I have heard about running the S8 nozzle as well. Might be worth a shot

 

[shnalln]

http://www.ericgorr.com/twostktech/carbtuning.html

Check this out, I followed this on my '02 and it worked great. I'm no expert either, but from my understanding your main is definately rich, and air leaks would make you lean right? Well, good luck!

 

[whitesands26]

No problems here....400ft. elevation 90 degree temps and all I did was adjust the ariscrew and go to a 410 main..Runs clean and crisp.

 

[Zero]

I sold my 02 CR250 beacause of the carb problems. I got sick of the BS. Its not worth it. I could only get it jetted right in cooler weather, once it heated up and the humidity started to get thick...forget about it. Nothing I did to the carb helped.

I now ride blue because of it.

 

[john stu]

murphys law my cr runs good now but it took a lot of tinkering i am running a 400 main, s-8 nozzle,6beh2-72 needle in the second clip,32.5 pilot air screw at 1 1/2 turns but the bike was ported buy eric gorr and has an sst pipe with a moto tassenari reed cage so my jetting might be a little different than yours right now the bike seems to run good pulls hard and i haven't noticed it wanting to load up the plug i tried smaller main jets but it seemed best with the 400 any smaller and it didn't seem to pull as long on top but like i said our bikes have differant pipes and porting and reed valves so they will be different.if i were you i would try the needle i am running with a bigger main jet i am willing to bet you will get that over-rev you are looking for my cr revs like a 125 and im not kidding!!!but then again i do have a top end pipe and a reed valve but i still would give it a try because even stock i ran that needle and it worked better than 6bey30-76 in the 2nd clip pos as far as running clean and that made it possable to run a bigger main jet and get that over-rev try it if you don't like it put it back to where you have it now.that needle (6beh2-72)is an opional needle for a 2001 cr250 so order it for the 2001 cr 250 for you dealer.in the worst case you will be out $15 if you don't like it its worth a try.let me know how it works out if you deside to try it.

 

[CR_Dave]

ok. did not give up yet.

i thought i might be chasing an air leak. i got new gaskets for the reed cage that was just put on. did everything real nice and neat and was very careful. Then ran the engine and sprayed some carb cleaner around the cage, cylinder, crankcase seal to see if the engine whined showing a leak. Nothing.

Went to:

390 main
2.25 a/s
1st clip on stock #73 needle
30 pilot
new br8eg plug
clean air filter - new
vp c12 at 32:1 with redline oil

checked the tension and adjusted the RC valve

and now..... it seems pretty good. need to get it on a track to test it. very crisp on the bottom. just hope i am not too lean. still a slight crackle on the top. might try a 380 main depending on how the plug looks.

 

[dav06]

Boy, I hate you're going through that. Sure confirms I made the right move. I spent all year tinkering with my 01 CR, I changed everything several times. I thought for sure it cant happen again, then I learned my 02 was just like the 01 only it didn't smoke the pits up when cold. First place I even started that bike, "I thought man I hope this is a temporary thing" Not. Now I have an 03 YZ250, you just can't imagine how nice it is not even having to touch the carb!

 

[IRISHCOFFEE]

dav06, i am still on a 01 cr250. how long did it take to adapt to handling differences and feel of bike? also, is the suspension easier to tune? i have found it impossible to get the harshness out of the forks without making the overall action too soft. thanks.

 

[CR_Dave]

I had a 2000 CR250 and still have a 2000 CR125 (132 by Mr. Gorr). Not a big difference. The vibration does seem to be a lot less. But I have really increased my physical conditioning and think that has really helped with the bike. I have not done anything special with the suspension, I did on the 2000 and it made a huge difference. Just playing with the clickers right now seems to do the trick. It is still pretty harsh in the fast bumps kind of stuff, but I think I can get it. So I guess the same problem that you are having does exist. My forks on the 2000 were done by Pro-Action. Did a nice job and they were local in Western PA. I still think the work done on the 2000 suspension is better than what I have today. But then again, I don't have $500 to get me new suspension fixes right now.

I kept the bike stock until now, knowing that things get banged up and beat up early in the season. I can pull holeshots over any bike with this thing stock. Had to run race gas to get rid of the detonation though.

I would keep your 2000 until the 04s come out. Hopefully we will see the new frame, but not likely. Or hold out for the four stroke.

 

[dav06]

IRISHCOFFEE,

If you are asking about adapting to the CR, I never really did. I was a local pro in my early 20's, now I'm 32. I was a die hard Honda fan, and after being out of the sport for several years my mind told me I was the same rider, so I wanted the same brand. I wanted another Honda. I went and bought my 01 without any research. First thing I noticed (except the smoke) was it felt like the ultimate 125, wore me out, beat me with harshness, and of course was terribly rich, and then everything in between while trying to remedy. I'm older and much slower now, but between the jetting, and the way the bike felt to me, I wasn't enjoying the sport. It was weird feeling remembering how I used to feel I couldn't live without it, and now this. Anyway I can't say much about the Yz yet, I've only had it two months and six weeks have been with a cast on. That's how good the bike felt, like it would hold any line, but I found one it would not :) The YZ has some bottom so I'm not having to rev it to the moon riding a controlled explosion from turn to turn. Many may disagree, but especially the 01 CR just didn't feel like a 250 to me. More suited to the rev monsters from the tiddler class who don't notice that big gap you can't "tune"

 

[IRISHCOFFEE]

davo6, sorry i was not clear. i was asking about adapting to the yammie. i have been on cr250s since 86. i had a 2000 and now a 01 and just cannot get the feel i had with the steel frame bikes. and yes, the motor is not the same either.. i have been thinking about the yz but just have been hesitant since i have had total reliability and great resale with the crs. thanks again.

 

[motometal]

those of you talking about actually switching brands or not buying a Honda due to jetting considerations, I wish you could be here to take a lap or two on my '03.  I have spent less than $10 and just a few minutes jetting it, and everyone who has tried it out can't believe how crisp it runs.  I have yet to foul a plug.  I'm gonna throw out a bit of advice:

1.  If your float level is set too high, you will NEVER get the jetting right!  If you can make it drool by wiggling the bike when it's vertical, it's probably too high.  If your rear brake disk guard is covered with oily goo (from the overflow hose), it's probably too high.

2.  I notice I am running a leaner pilot than most people, 27.5 with air screw 2 - 2.5.

3.  If you are leaning out your jetting, I wouldn't wait until you hear pinging to start using race fuel.  This is your insurance, your safety factor.  If you are serious about it, study race fuel characteristics here on DRN and choose your poison accordingly.  Those of you trying to pin down jetting while still running pump fuel don't have a licence to whine.

4.  Honda suspension, in my opinion, has been pretty good since 2000.  One thing I noticed on the '03, the forks actually got less harsh when I turned the compression clicker in a ways.  Turns out I was diving through the first half of the travel quickly, then hitting the stiff or "harsh" part.  Find a good track and spend an hour or two changing only one thing at a time, pay attention, and document.

 

 

[IRISHCOFFEE]

motometal, i appreciate your post on the 03. i have solved the jetting thing but have found NO cure for the harshness of the forks. i have used mxtech, and another suspension guru in colorado who i have absolute faith in and am worse off than stock. i have been fortunate to ride from ms. to oregon and still feel that t east TEXAS and louisiana roots rule the forest. the work of the devil. i have heard the susp. on the 03 is better and i truly want another honda but am just skeptical. thanks for your input.

 

[whitesands26]

Wow, amazing how many switch because of jetting...Maybe I'm just lucky because mine runs extremely strong...I've even had many compliments from different individuals just on how strong it sounds at the track...And all I've down is leaned the main to a 410 and turned the air screw out...

 

[bedell99]

Motometal wrote a very good post. Before you start to even think to jet this bike, start with the basic's. Float bowl height was a problem on my CR and was a mjor cause to my jetting woes in the beginning. Also I keep my rave gas consistent with using phillips B32 (TrackTek111). It is a pain to jet this bike correctly and I also noticed, that most people where going in the wrong direction especially making it way too lean in most circuits. This bike needs to be ridden hard.

Erik

 

[dav06]

That was my thinking with 01 as well. That's what gave me my ill feelings, when the bike came out I thought I could fix it with the basics, no better with carb settings, and all the dealer could tell me was float height which I had already checked. I ended up spending that summer with the carb tore apart in the pits so much I think I could have done it in the dark. I ended up running a 400 main, much leaner needle, can't remember #, 25 pilot, the leaner nozzle which made the biggest diff, and the air screw varied with temps. Race gas of course. I'm in Fla, sea level, this worked great until that winter. My biggest gripe was just that the bike was so hard to ride, the faster you are the better it is, I'll give you that. The YZ is just broader, easier to ride. The CR feels like what I needed in the late 80's early 90's when I was coming off 125's and still riding my 250 the same way.

 

[dav06]

Oh, and the best part...My Honda dealer would not budge on a CR, or a KX either. I ended up driving 3 hours and got my YZ for $4800 OTD! Enough to sway me.

 

[CR_Dave]

After a bunch of testing and very carefull re-assembly of the reed cage and carb, I GOT IT. The power is smooth and crisp. It almost feels like it is ready to blow up, but it has not and everything is fine. There must have been an air leak I was chasing. Ended up with a 380 main, 30 pilot, 1st clip from top on #73 needle.

Hehehehehehehheheeeeee!!!!!!!!!!

 

[NO HAND]

My 03cr250 is stock right now and the stock jetting was awful too. I gave a try to the MXA jetting specs. I know very often MXA are way off, but in the case of the 03cr250 I think it was pretty much in the ball park. They say: main 400, needle 6BHY38-70, 1st clip, 40 low speed, 1.5 turns out. I found it so much better across the whole powerband, like night and day.