My new '99 carb is here....so I have a question.

[SilverSurfer]

I'm not really sure about the over-rev, but it seems to run pretty clean and make great power at WOT. I am running an FMF Gnarly pipe with a Turbine Core II spark arrestor.

Ok that is where we differ. I have the FMF Fatty. Otherwise I have the same spark arrestor.

I will swap to the 190 and see if that makes any difference.

[bikepilot1]

Dumb question, but have you cleaned the filter in the tank lately? A partilly blocked one can cause a lean condition up top as it might not flow enough to keep the float bowl full when flat out.

BTW my 01 with FMF Fatty and Turbine Core II pulls very strong up top (tested this extensivly chasing a bunch of pro GNCC/Enduro guys on CRF450's around a huge grass track last summer - the straights were the one place I didn't get left behind:). Still have the mikuni carb, 420 main, S-7 nozzle and 32.5 main jet, sea level and 60 deg F its nearly perfect IIRC.

good luck

[skipn8r]

I will swap to the 190 and see if that makes any difference.

Give it a shot. But for reference, jetting is throttle opening dependent, not RPM dependent. If the bike runs great at WOT and midrange RPM but goes flat at WOT and high RPM, the problem is not with the MJ.

[SilverSurfer]

Give it a shot. But for reference, jetting is throttle opening dependent, not RPM dependent. If the bike runs great at WOT and midrange RPM but goes flat at WOT and high RPM, the problem is not with the MJ.

I agree. But down low and mid it's perfect. Up top is just has nothing. If the MJ is too small then going up on the main and adjusting the needle may be just what the doctor ordered. I can tell you this, right now I am willing to try anything to get the bike to put some power up top! LOL

[SilverSurfer]

Well I put the 190 in there and it runs worse. In fact, it was surging at idle and spewing excess fuel. Definitely a 190 is too much.....

I still think it's the crappy Fatty pipe....

[PGer555]

I also have the 99 carb on my 01 with the fmf fatty and right now im using a 180 main, 42 pilot, stock needle 2nd clip, and 2.5 turns out on as. Its still a little rich... Does anyone know what the next leaner needle is after the stock needle in the 99? im not sure on the number, ill have to check motosports oem catalog...

Also, im not sure if this could be your problem but it might be one of mine. If the float level is off, will the bike run rich? I thought i read that somewhere, but im not 100% sure...

[SilverSurfer]

I also have the 99 carb on my 01 with the fmf fatty and right now im using a 180 main, 42 pilot, stock needle 2nd clip, and 2.5 turns out on as. Its still a little rich... Does anyone know what the next leaner needle is after the stock needle in the 99? im not sure on the number, ill have to check motosports oem catalog...

Also, im not sure if this could be your problem but it might be one of mine. If the float level is off, will the bike run rich? I thought i read that somewhere, but im not 100% sure...

Yes, if the float is off it will run rich.

I'm going back to the 175 and will put the needle at the #2 clip to see if that helps. I'm going to see if I can find a stock exhaust to check. If that doesn't work I am taking it to the dealer. I am tired of fighting this bike, haha.

[skipn8r]

Does anyone know what the next leaner needle is after the stock needle in the 99?

A little background. The stock '99 needle is R1370DKA. The 13 represents the taper, and I'd leave it alone. The 70 represents the needle diameter and the D represents the clip position cut. The optional needle set for '99 includes needle diameters 68 - 72 and clip positions D and E for each diameter for a total of ten available needles including stock. You can get all of these needles directly from Honda and the SH fiche site litsts them all. Keihin has a pretty good jetting chart that shows how different changes affect the jetting.

The slow jet (SJ) and needle diameter affect jetting in the 0 - 1/2 throttle range; a smaller SJ and a larger needle diameter both lean the mixture. Clip position affects jetting in the 1/8 - 3/4 throttle range; raising the needle clip drops the needle which leans the mixture. The D represents the standard clip position cut for '99 and the E needles are cut 1/2 clip leaner than the corresponding D needles.

Now, if you want to lean your jetting between 0 and 1/2 throttle, you want to install a smaller PJ and/or use a needle with a larger diameter (71 or 72). If you want to lean your jetting in the 1/8 - 3/4 throttle range, you either want to drop your existing needle one clip or get an E needle to split the difference between clip positions on your existing needle.

Compared to the stock needle, an R1371EKA (PN 16233-KZ3-J11) would be one "step" leaner in the 0 - 3/4 throttle range (for a given clip position). As always, verify part numbers before ordering.

Make sense?

[SilverSurfer]

A little background. The stock '99 needle is R1370DKA. The 13 represents the taper, and I'd leave it alone. The 70 represents the needle diameter and the D represents the clip position cut. The optional needle set for '99 includes needle diameters 68 - 72 and clip positions D and E for each diameter for a total of ten available needles including stock. You can get all of these needles directly from Honda and the SH fiche site litsts them all. Keihin has a pretty good jetting chart that shows how different changes affect the jetting.

The slow jet (SJ) and needle diameter affect jetting in the 0 - 1/2 throttle range; a smaller SJ and a larger needle diameter both lean the mixture. Clip position affects jetting in the 1/8 - 3/4 throttle range; raising the needle clip drops the needle which leans the mixture. The D represents the standard clip position cut for '99 and the E needles are cut 1/2 clip leaner than the corresponding D needles.

Now, if you want to lean your jetting between 0 and 1/2 throttle, you want to install a smaller PJ and/or use a needle with a larger diameter (71 or 72). If you want to lean your jetting in the 1/8 - 3/4 throttle range, you either want to drop your existing needle one clip or get an E needle to split the difference between clip positions on your existing needle.

Compared to the stock needle, an R1371EKA (PN 16233-KZ3-J11) would be one "step" leaner in the 0 - 3/4 throttle range (for a given clip position). As always, verify part numbers before ordering.

Make sense?

All of that makes complete sense. What is bugging me is that no matter what I do, it does not effect to top end rev range.

New carb? No effect.

Bigger MJ? No effect.

Pull choke at WOT? No effect.

The ONLY thing I have not done is change the pipe to see if that is the culprit. With the 75mj and everything on the carb set to stock the throttle response was PERFECT - except on the top end where it just falls flat. No matter what I do or change on the bike, it won't pull hard on the top end like a solid 250 2 stroke should. That has me flabbergasted.

Now, if I eventually find a stock pipe to test my theory out and that works, then I have found the problem. If I do and it doesn't change the top end then maybe I will go back and check the reeds, check the exhaust valve again or I may just see if I can find a new cylinder and redo the top end.

I am really tired of this problem. Maybe taking it to a dealer will help?

[PGer555]

A little background. The stock '99 needle is R1370DKA. The 13 represents the taper, and I'd leave it alone. The 70 represents the needle diameter and the D represents the clip position cut. The optional needle set for '99 includes needle diameters 68 - 72 and clip positions D and E for each diameter for a total of ten available needles including stock. You can get all of these needles directly from Honda and the SH fiche site litsts them all. Keihin has a pretty good jetting chart that shows how different changes affect the jetting.

The slow jet (SJ) and needle diameter affect jetting in the 0 - 1/2 throttle range; a smaller SJ and a larger needle diameter both lean the mixture. Clip position affects jetting in the 1/8 - 3/4 throttle range; raising the needle clip drops the needle which leans the mixture. The D represents the standard clip position cut for '99 and the E needles are cut 1/2 clip leaner than the corresponding D needles.

Now, if you want to lean your jetting between 0 and 1/2 throttle, you want to install a smaller PJ and/or use a needle with a larger diameter (71 or 72). If you want to lean your jetting in the 1/8 - 3/4 throttle range, you either want to drop your existing needle one clip or get an E needle to split the difference between clip positions on your existing needle.

Compared to the stock needle, an R1371EKA (PN 16233-KZ3-J11) would be one "step" leaner in the 0 - 3/4 throttle range (for a given clip position). As always, verify part numbers before ordering.

Make sense?

Thank you for clearing that up!

Man i wish we had fuel injection...

[punkrock MX]

maybe your gears are slipping or something..my friends 04 yz250 had 3rd and 4th gear go out (this was a recall on 04 yz250s i believe) and the bike would miss on top like it was jetted to rich or it was cutting out

pger..just get a few smaller pilots and see what you like...42 seems REALLY lean to me..maybe my bike aint running right but it was pretty lean with the stock 48 the 00' came with..im runnning a 52 in there now (on purpose)

IMO the rich jetting softens the hit and makes it easier for me to hang on too..

[punkrock MX]

oh yea dont take it to a dealer unless you know the mechanic is smeone with a brain

i wouldnt take it to a dealership, no point in paying to get bent over at the parts counter and taking it in the rear

[skipn8r]

pger..just get a few smaller pilots and see what you like...42 seems REALLY lean to me..maybe my bike aint running right but it was pretty lean with the stock 48 the 00' came with..im runnning a 52 in there now (on purpose)

The SJ you end up with will depend on the needle you use and the '00/'99 needles are fairly different. What were the lean symptoms that made you switch to a 52?

[punkrock MX]

oops..forgot about the needles skip

umm..it ran kinda zingy off idle and the temps have dropped since summer (i stopped riding for the season last week) but before that the plug was alittle to 'white' for me and i didnt want to chance it since i do alot of sand riding and the moto tracks around' here are nice and loamy in the morning..

everything is on the rich side of the equation for my jetting, but it dont spooge

oh yea..i also heard that if you're running at high RPM, even if the main jet is big enough the pilot can still be to small which would make a lean condition (correct me if im wrong)..im not all that fast on a moto track but i can wick' it up for a lap or 3, that combined with sand, big sand whoops and more deep sand..made me kind of cautious about it. i figure the tad richer jetting is cheap insurance

[SilverSurfer]

oops..forgot about the needles skip

umm..it ran kinda zingy off idle and the temps have dropped since summer (i stopped riding for the season last week) but before that the plug was alittle to 'white' for me and i didnt want to chance it since i do alot of sand riding and the moto tracks around' here are nice and loamy in the morning..

everything is on the rich side of the equation for my jetting, but it dont spooge

oh yea..i also heard that if you're running at high RPM, even if the main jet is big enough the pilot can still be to small which would make a lean condition (correct me if im wrong)..im not all that fast on a moto track but i can wick' it up for a lap or 3, that combined with sand, big sand whoops and more deep sand..made me kind of cautious about it. i figure the tad richer jetting is cheap insurance

What are the characteristics of a bad CDI? Would the bike even run at all if the CDI was bad? Could it be possible that the CDI isn't working right in the upper RPM band and that is keeping the bike from really taking off like it should?

I really don't think it's jetting. It ran GREAT with the 175 main and the stock pilot and needle settings, it just would not rev out like a normal 2 stroke does. I tried talking to a tech today but the guy was a total jerk and wouldn't even let me finish my sentences.

I will try the WOT jetting test to see if the plug is lean or rich (or perfect) at WOT.

FWIW, the bike ALWAYS fires up on the first kick and low to mid throttle is perfect. Best throttle response I've ever seen on a 2 stroke. It just won't do much on the top end at all.

[gnarly_carl]

You might try Ebay or craigslist for a CDI or if you have a buddy with a similar bike you might try swapping.

[SilverSurfer]

You might try Ebay or craigslist for a CDI or if you have a buddy with a similar bike you might try swapping.

I don't

Is there no way to test the CDI before I go dropping more cash to fix a problem that may or may not exist?

[PGer555]

pger..just get a few smaller pilots and see what you like...42 seems REALLY lean to me..maybe my bike aint running right but it was pretty lean with the stock 48 the 00' came with..im runnning a 52 in there now (on purpose)

The first SJ i tried was a 50 and that was way too rich. I have only been able to ride by my house and the surrounding woods, and its all 0-1/2 throttle. Nothing wide open. Just from that i was getting splooge from the end of the silencer and from where the silencer and pipe meet. So i threw in the the stock 42 SJ and raised the needle to the 1st clip(thats why i asked about the next leanest needle). The splooge is alot better, but it still exists... So i guess ill have to try a 40 SJ. I also think my float level is off, i gotta check that one of these days...

[SilverSurfer]

The first SJ i tried was a 50 and that was way too rich. I have only been able to ride by my house and the surrounding woods, and its all 0-1/2 throttle. Nothing wide open. Just from that i was getting splooge from the end of the silencer and from where the silencer and pipe meet. So i threw in the the stock 42 SJ and raised the needle to the 1st clip(thats why i asked about the next leanest needle). The splooge is alot better, but it still exists... So i guess ill have to try a 40 SJ. I also think my float level is off, i gotta check that one of these days...

I have no issues with splooge. My bike runs GREAT down low. In fact from 0-75% throttle it runs and behaves like a normal cr250.

It's that last 25% of the throttle where it pulls like with about 1/4-1/2 of the power and thrust I expected. Certainly nothing like a stock cr250 would.