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Help out w/Powerjet ?'s

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Hillclimb#42:
 :-D Yeah its a 200cc Class. It just worked out for us, so far. The bike has some cool history. It was my Teammate Paul's first Hillclimber, and he now is rippin up a Triple. He basically gave it to us to fix up. It took alot more than I thought, but we got it together and I was the only person who wanted to ride it. (I'm the lightest) Its my first stretched bike to race. It is a total Frakenstein. Every spare part from Honda's and Kawasaki's that we had, were thrown at it, and everyone got a hand in on working(and paying) on it. We chased the carb problems around with spare parts, too. The Cr500 carb that we tried first was from a Pro Hillclimb cr500 set-up to run alcohol. Its been in a box since the 90's. We of course, switched to standard jets, but think the needle may have been worked on to add to fuel flow. This other carb from a 250, was a spare from another buddies bike, who swapped it out for a Lectron. Its kind of a low budget, high labor project, I'll admit. The 250 and the 500 are less of an experiment by nature.
  thanks for the advice, Don. We are gonna keep our ears open for a 125 carb, 36mm. We noticed that the carb was closer to the cylinder, and am glad that you agree with what we thought that did to perfomance. I am used to lots of mid range, but some people build for top end, others for bottom. Its revving good, so far, but there's always more...

DoldGuy:
#42,
I have a PWK 36mm willing to swap out for the 99 KX250 carb if interested.

Don,
The 93 KX125 (in my opinion) is the strongest motor for topend they have made and they came with a 36mm carb, as mentioned earlier, running a 39PWK on my 93 and it runs pretty strong. I don't think Kawi has ever put a 38 on a KX125 from the factory, but has used the 35mm for a couple of years ( maybe good for #42 & his KDX200?)

Hillclimb#42:
Thanks for the offer, Doldguy. We are sticking with this one for now. We put in some new clutches and springs, geared up from 13-45 to 14-47, and plan on being in the hunt this weekend. The 200 is running well. It has been sounding just like a 250, but pulled like an old mule. We thought the clutches were slipping a little, since it was screaming sounding, but not an abrupt launch. If it was, it was hard to test, but we bought new clutches just in case. We discovered that the new springs were at least 1/4" longer. Now the clutch lever has the spring tension, it should have.
--- Quote from: DoldGuy on June 02, 2009, 12:30:07 PM ---#42,
The powerjet circuit solenoid is in an open position at all times until it gets a signal from the CDI to close at about 8500 rpm (if memory serves me) to lean out the motor producing a hotter Exhaust Gas which in turn speeds up the reflection wave in the pipe allowing the short circuited charge time to be stuffed back in the cylinder before the piston closes the exhaust. If you notice the heighth of the dump tube of the PJ it is set at approx 1/2 slide height (midrange) and that is where most motors have the biggest load & needs the most fuel. If you are currently using a lectron (PJ installed?) start the motor & watch the PJ fuel line to see the fuel start moving at about 1/2 throttle as it uses the same principal. I would think (?) a tuned 200 would take a 38mm carb as I use a 39 on a 125 (& yes it has NO bottom, Great mid & top) that is used for drags, but maybe you guys need a much broader power spread. Another good thing about the PJ PWK is that you have an additional jetting capability with the PJ (has it's own jet) circuit eve with out it hooked up electronically. Hope  some of this helps out in using what you have.

--- End quote ---
 
doldguy, 
The PJ must be activated by the frame mounted diode/rectifier. The test is supposed to give voltage rising in relation to the rpm's when tested at the diode. What are you saying about the powerjet circuit? It still affects performance even though its not hooked up? What's it doin without being hooked up? The PJ concept still has me confused, not discounting your info.
  There is small amount of powervalve pre-load adjustment. Would it help anything to keep the powervalves closed a little longer to recover some of the lost bottom end? Thanks again for your input.

Hillclimb#42:
Got a couple more ?'s. We got the Mikuni back out and was talking about testing the differences between the Kehin and the oem mikuni. After a closer look, we noticed that the Carb has been bored. It looks to be about 2mm bigger than it was originally. Then we also noticed the slide has been machined. The bottom angle has been changed to a steeper angle.
 We were advised that the fast 200's on the east Coast, all ran their Airboxes, so we wanted to try that. For those of you not familiar with the old KDX's, they mounted the Air box at a 90 degree angle to the carb. The air intake is right up under the seat. How would you guess that more air restriction would help make it faster? What does changing the slide angle do to performance? Boring the carb out will help top-end, right? With these mods, am I better off running this Mikuni?

don46:

--- Quote from: DoldGuy on June 05, 2009, 01:33:00 PM ---#42,
I have a PWK 36mm willing to swap out for the 99 KX250 carb if interested.

Don,
The 93 KX125 (in my opinion) is the strongest motor for topend they have made and they came with a 36mm carb, as mentioned earlier, running a 39PWK on my 93 and it runs pretty strong. I don't think Kawi has ever put a 38 on a KX125 from the factory, but has used the 35mm for a couple of years ( maybe good for #42 & his KDX200?)

--- End quote ---

Can't remember if it was the 93, 94, or 95 that came with a 38mm carb, but they did and also had a 6 petal reed cage, whatever year they were rockets, in fact I bought a 38 carb and the matching reed cage and used it on all the future 125's until they added a powerjet in 99, then I had them bored to 38's

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