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97, 03 Cr250

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I have been out of riding way to long.

Questions....

First question 97 - CR250 What is the wiring going to the carb? Air flow sensor?

Second question 03 - CR250 When did the CR 250 change to a flat slide carb?

I thought those were used on allot of european bikes early on (I'm probably wrong), and they weren't that good.

Why are they being used now, and what makes them better, if anything?

:thumbsup:

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the wiring on the 97 is the power jet solinoid , and the cr 250 went to the flat slide TMX in 2001... :thumbsup:

*edit* there are a lot of theories as to why honda went to the TMX, but the easiest answer is weight.its a few grams lighter than the PWK. my best freind is one of the honda test riders, and even he doesnt know why they switched for sure....when they were testing carbs, every test rider voted for the PWK, but honda went with the TMX anyway.....

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the wiring on the 97 is the power jet solinoid , and the cr 250 went to the flat slide TMX in 2001... :thumbsup:

*edit* there are a lot of theories as to why honda went to the TMX, but the easiest answer is weight.its a few grams lighter than the PWK. my best freind is one of the honda test riders, and even he doesnt know why they switched for sure....when they were testing carbs, every test rider voted for the PWK, but honda went with the TMX anyway.....

Wow! Sounds like my company! :applause:

Thanks :applause:

I am a person that likes to know how something works, because then you are better able to fix it or tweak it. The power jet solenoid confuses me. I'm gonna do a google search and if I can't find my answers, I may be back to bug you. If I may. :applause:

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i got this from motorcycle online...

The powerjet carb is sort of confusing in tech talk. Honda's wording is: "The powerjet starts to flow fuel at about 1/4 throttle. This is when the engine has created enough vacuum to pull the fuel up through the powerjet valve and will continue to flow fuel until 8,100 rpm, at which time the powerjet solenoid is turned on closing the powerjet valve." Basically the valve stays open whenever the revs are below 8,100, offering crisper throttle response. Though you would think with the powerjet the motor would use more fuel, Honda states it actually gets slightly better mileage.

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chris, didnt you said you can disconnect the powerjet and change the needle to get it to work properly without it?

id do that if i had one of those bikes..im using a pwk on my 01 and it runs really good..i have it jetted alittle to the rich side of the equation to help smooth power delivery and it pulls hard. that damn fmf pipes gives it a nasty hit that im still getting used

too..:thumbsup:

its too bad honda didnt stick with the cylinder-reed motor with the CRV valve instead of the case/rc valve, im sure they could of improved on the old design and mated it with the new chassis. i wonder how good the bike could of ran with TODAYS technology with the powerjet.

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chris, didnt you said you can disconnect the powerjet and change the needle to get it to work properly without it?

id do that if i had one of those bikes..im using a pwk on my 01 and it runs really good..i have it jetted alittle to the rich side of the equation to help smooth power delivery and it pulls hard. that damn fmf pipes gives it a nasty hit that im still getting used

too..:thumbsup:

its too bad honda didnt stick with the cylinder-reed motor with the CRV valve instead of the case/rc valve, im sure they could of improved on the old design and mated it with the new chassis. i wonder how good the bike could of ran with TODAYS technology with the powerjet.

yeah, most of the people that ran into solinoid problems just disconnected it, and swapped the stock needle for the 1368ns, and then played with the main jets from there...

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fmf pipes gives it a nasty hit that im still getting used

too

Which FMF pipe are you running?

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fatty + powercore II silencer..i was using a pc works pipe with a r304 silencer and it defintly didnt hit has hard..

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fatty + powercore II silencer..i was using a pc works pipe with a r304 silencer and it defintly didnt hit has hard..

I just ordered the same setup sunday night. Dang rockymountain shipping takes forever tho. I wont have it till 9/06...

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i got this from motorcycle online...

The powerjet carb is sort of confusing in tech talk. Honda's wording is: "The powerjet starts to flow fuel at about 1/4 throttle. This is when the engine has created enough vacuum to pull the fuel up through the powerjet valve and will continue to flow fuel until 8,100 rpm, at which time the powerjet solenoid is turned on closing the powerjet valve." Basically the valve stays open whenever the revs are below 8,100, offering crisper throttle response. Though you would think with the powerjet the motor would use more fuel, Honda states it actually gets slightly better mileage.

I saw this article also, kinda weak huh.

I really can't look to deep into anymore. It started bringing back memories and emotions.

The 97 is my friends bike. It sucks, because we were just cleaning out all of the bugs, and he crashed on it and then passed away at the beginning of April. :applause:

I did look at my 03 manual remembering it has the electrical diagram on it, and now I see I can learn something about the RC Valve control. I've posted up about that and have gotten different stories about it's operation. I see that it appears to have a servo motor, since there is a feedback signal from the motor. So I am going to hook up my oscilloscope to find out if the motor (and thereby the Valves) are actually linear to the rpm, or if it just opens and closes at a certain rpm.

punkrock MX

"its too bad honda didnt stick with the cylinder-reed motor with the CRV valve instead of the case/rc valve"

I agree 100%

Especially since this is electrically controlled. My question on the RC is if it starts getting carboned up and starts to stick will the electronics see the current draw and stop trying to move, or will it keep trying to operate, and then burn something up. IE..wires, servo motor,or ECU? :thumbsup:

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still kicking

sc_spode said it is linear to rpm changes..hes a guru or something..hehe

i dont think the RC valves 'timing' has anything to do with the less then stellar performance that everyone complains about, i think the actual seal it makes is where its problem lies. ktm's 250 sx is case reed and has a mechanical powervalve..the motor rips..more then a yz even! they also have adjustable powervalves that use color coded springs to govern how long it takes to open..im thinking the stiffer the spring, the harder the bike will hit because it will have to rev up more to get it to open all the way, and it'd be the opposite with a softer spring. i know the 125 has this along with another type of internal adjuster, im not sure about the 250's though. that being said..im pretty sure their PV design seals alot better.

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I saw this article also, kinda weak huh.

I really can't look to deep into anymore. It started bringing back memories and emotions.

The 97 is my friends bike. It sucks, because we were just cleaning out all of the bugs, and he crashed on it and then passed away at the beginning of April. :applause:

I did look at my 03 manual remembering it has the electrical diagram on it, and now I see I can learn something about the RC Valve control. I've posted up about that and have gotten different stories about it's operation. I see that it appears to have a servo motor, since there is a feedback signal from the motor. So I am going to hook up my oscilloscope to find out if the motor (and thereby the Valves) are actually linear to the rpm, or if it just opens and closes at a certain rpm.

damn, thats not cool about your bud...

you could try to search around for some info on the nsr250's for more tuning info, since that bike is where the rc valve came from. it worked great on the pavement, but a lot of people are still scratching their heads in the dirt.

luckily, i wont need to worry about the case reed junk. i have been acquiring parts and engines for the cyl. reed engines for a few years, and have enough now, to keep this bike fresh for a decade or two... :thumbsup:

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Ihe crashed on it and then passed away at the beginning of April. :applause:
Sorry about your friend. Man, that really sucks.
So I am going to hook up my oscilloscope to find out if the motor (and thereby the Valves) are actually linear to the rpm, or if it just opens and closes at a certain rpm.
Your own scope. Cool :thumbsup: . Post what you find.

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I saw this article also, kinda weak huh.

So I am going to hook up my oscilloscope to find out if the motor (and thereby the Valves) are actually linear to the rpm, or if it just opens and closes at a certain rpm.

I'm pretty sure they just open at a certain rpm .

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I'm pretty sure they just open at a certain rpm .

That would be in direct contradiction to what I found (and skipn8r reinforced) here.

:thumbsup:

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That would be in direct contradiction to what I found (and skipn8r reinforced) here.

:thumbsup:

hmm, I will hafe too check mine again. I belive it's lacking a little bit and don't start opening that soon. My cables are adjusted, hmm wonder how I could get it too open a bit quicker.

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That would be in direct contradiction to what I found (and skipn8r reinforced) here.

:applause:

I hear you and believe you Spode, and with the scope we can prove it!

If I can get the software :applause: to work on my laptop, I can take a screen shot of the trace!

Then we can put all the doubting toms to sleep. :applause:

:thumbsup: Now where did I put my Tach...hmmm

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my dad has a few osi-scopes, i know one of them is worth a shitload of money (30g's +?) but i think its probably at his workplace, but if i get my 03 soon i can ask him to try to take a reading

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I hear you and believe you Spode, and with the scope we can prove it!

If I can get the software :applause: to work on my laptop, I can take a screen shot of the trace!

Then we can put all the doubting toms to sleep. :applause:

:thumbsup: Now where did I put my Tach...hmmm

Update; Ok, so I get all set up Friday night to do the test. Took apart my Tach so I can connect oscilloscope to it too. I get up in the morning and there is a message on my company cell phone! :ride:

So here I am in Buffalo, NY Didn't get to make the test, or ride this weekend!! :ride:

Being a Service Tech sux!!! :applause:

Looks like it will wait until next weekend. :applause:

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