01 cr250 falls on its face up top

New to me, new top end, gnarly pipe, new Q silence, new clean airfilter, new plug. stock carb/jets which are cleaned spotless. This thing starts and idles great, has a very very very brief mid range and nothing on top, just sputters almost like the choke is on. could this be a clutch slipping issue?

I did search, i know i should do the airstriker swap and play with jetting, but this thing should have at least a hint of top end even if it is jetted poorly for the pipe/silencer combo.

The stock carb has worked fine. i had a cr125 and never had to touch the jetting. I do not race and i do not need it jetted for max/perfect power. just need it to run harder than the 125 i had, right now it doesn't.

What do you think, change the main jet, change the pipe combo, how would i tell if it's something completely different... like the clutch?

Sorry this is so long, i had it layed out alot nicer the first time but it logged me off.

Thanks in advance and if you would rather me just continue searching i most certainly will....you've all pretty much answered every other question i've had by lurking and searching, that's why i don't have any posts, thanks again.

jd jet kit should be in your future i think, or that"new" top end isn't so new after the 150 hours they put on that piston:smirk:

cracking and sputtering and shit i would think that you need to drop a few sizes on the main jet. If its bogging your too lean and need to go richer.

jd jet kit should be in your future i think, or that"new" top end isn't so new after the 150 hours they put on that piston:smirk:

Ha, right on....that's what i would think also accept, i had the honda shop do it. They don't have any room in their lot to really run it, they told me it runs great....i don't think so.

cracking and sputtering and shit i would think that you need to drop a few sizes on the main jet. If its bogging your too lean and need to go richer.

No bog, just goes totally flat. So this does sound like a jetting issue only? Not clutch or pipe combo? I will just get the airstriker if i have to start playing the jet game.

have you taken the power valve innspection plug out of the left side of the cylinder and check to see if the power valve is openning. start it up, it should be lined up with the L straight up and when you rev it it should open and point to the H towards the front of the bike. if it does not opening the motor will have power down low and just go flat when it start to pick up the rpms.

have you taken the power valve innspection plug out of the left side of the cylinder and check to see if the power valve is openning. start it up, it should be lined up with the L straight up and when you rev it it should open and point to the H towards the front of the bike. if it does not opening the motor will have power down low and just go flat when it start to pick up the rpms.

i read that on a search, but blew it off assuming the shop did this, they said they cleaned the pv. I will check it out, sounds simple enough. would be great if that was the problem. thnx

Just dropping your main jet a couple sizes down from stock should help. According to what I can find the stock main is a 420 and fmf recommends 400 main and the needle in the 2nd position, stock for the needle is 3rd position. Get a leaner main and move the clip and see how it rides.

my bike did the same thing the other day.....ran perfect down low and in the mid range. Then once you crack her wide open it ran like balls...it was too warm outside. Dropped the main jet from a 460 to a 450 and it ran way better; then dropped to a 440 and it ran perfect.

did you get her fixed?

I brought it to a local shop, they are doing the forks. They also have a dyno. I will check out the power valve, see if that's working properly, then will prob just dyno tune with some different main jets.....unless someone else has some other ideas. I don't really want to pay $50 for the dyno, much more fun to just ride it and tune it. But, i'm kinda curious to see what she dynos.

Any other suggestions, before i waste the $50 bucks? thnx

About 8 years ago when I first got my 97 CR250 it would fall completely on its face and it was because the shop it was at didn't properly assemble the power valve. I would just check it before you do anything else. Just one plug to remove to check for proper operation. Very quick check.

if the actuator fork on the bottom of the cylinder doesn't get aligned on the rod from the lower end the power valve won't open. it is possible to assemble the engine and misalign this and it will f your bike up.

look under the cover on the right side of our cylinder where the PV linkage is. There is a vertical shaft coming up through the PV arm and on the top there is a hair pin clip through it. the hole for the clip should facing straight out towrads you. if it is angled towards the back then the fork and pin under the clinder got assembled wrong

ok, so the left side plug just comes off to make sure the line is moving 90 dgrees, from L to H or vise versa. and i can just take the cover off the right side to check the actual pv without messing anything up? I actually can't wait to look at this stuff.....i hope it is in there correct. i will be really bumbed if the Honda dealership messed it up.

Taking the covers off won't mess anything up. the left cover has a 17mm nut but does not need to be torqued like a 17, just enought to seat after compressing the o-ring and then a little more.

Don't be bummed if the Honda shop messed up, just let them fix it. It'll only take you a minute to check normal operation of the PV. Hopefully they didn't install your piston backwards...either way it sounds like they are on the hook to correct it.

yup somthing isn't working right .. that thing should pull your arms off mid- top mine dose !!!!!!!!!

Same symptom I had, turned out to be a partial clogged carb. Clean out the carb and see if it fixes it.

have you taken the power valve innspection plug out of the left side of the cylinder and check to see if the power valve is openning. start it up, it should be lined up with the L straight up and when you rev it it should open and point to the H towards the front of the bike. if it does not opening the motor will have power down low and just go flat when it start to pick up the rpms.

Ok fellas,

I let it warm up, took the left side pv cover off. I see the groove(screw driver like groove) it is horizontal, facing the "H" when i give it rpms, it does not move at all, stays horizontal.

My service manual says it should be facing the "L", start the engine, increase engine speed, exhaust valve should turn 90 degrees to the "H" mark. If mine is on the "H" and never moves through the increase in rpms, am i correct to assume something was installed incorrectly by the Honda shop?

Am i missing something, seems too easy? And it seems like the Honda shop should know how to install this thing correctly.

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