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XRidiculous

Ron McCord's Pulse Charged Injection

15 posts in this topic

Despite what you may have read, I have a PCI unit on my '98 XR600, and it does work-in other words, it is a stupid amount of power to have in the woods!

But now I have to pass an emissions test to register in another state, and the jetting is not getting it.

Anybody know if he (Ron) is still around? I thought that maybe the database for tuning has increased, and I can make the proper adjustments to pass inspection.

Anyone....anyone?

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I'd like to find out too. I put a PCI kit on a '94 XR250 and kept the carb when I sold the bike. The aluminum tube that is bonded to the side of the carb is damaged and I would like to get a replacement.

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Well, here's the deal-and I dont mind elaborating, because this is pretty-trick.

Intake Gases (Gas and Air) are accelerated to almost the speed of sound when the intake valves open. When the valves shut, the gases hit the backside of the valves, and create a turbulence in flow. When the valves reopen, the flow resumes with some turbulence, and over and over...

PCI uses a manifold between the carb and head, with a nozzle, a measured loop, and a tube grafted to the side of the carb on the intake side.

Now, when the valve closes, the flow gets directed through the measured loop (different length on different bikes for timing purposes).

When the valve reopens the charge of gases finish the loop, and enter the cylinder.

So its a turbo, but using existing energy, not a blower.

End result-more power, worse gas mileage-but no real change to starting (easy).

The only thing I had to do was tune the rear shock, because I was not hooking up with all that power, just spraying rocks-which is not a bad thing depending on who is behind you.

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Excellent explanation XRediculous. I only tried it on the XR250, because the 400 and 600 made enough power to suit me. It was a worthwhile mod on the 250, a noticeable improvement in torque off idle right through the midrange, not much improvement in the upper rpm range. Did use a little more gas, but worth it. I stuck a 280 kit in the same bike, but with that setup, a Mikuni flat slide from XRs Only made a significant improvement over the McCord setup. Amazingly enough, after reading your post, I went through my junk and came up the literature and instructions. Here it is if you want to try:

McCord's Power Flow

854 Ginger Ave.

Billings, MT 59105 Phone: 406-248-5595

Good Luck :applause:

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Anyone try it without success ? Sounds a little like snake oil, kinda like the turbo twister thing for car intakes. Makes alittle sense about what you said but I would think a rather large tube would be needed to handle flow. Any dyno results ?

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No dyno results, just seat of the pants. For me, I just considered mods that didn't mess with reliability-and I bought my bike new in '98, and have NEVER broke the motor-not even a clutch yet.

I really cant fault the 600, and it has been the most reliable, and maintenance free bike I've ever had.

I know I'm running rich, and maybe a dyno is in my future.

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This is a variation on organ pipe tuning. The idea is to find the optimum runner length such that the pressure wave reflected back from the intake valve closing reflects back twords the intake valve just as it is opening, thus taking advantage of the energy in the pressure wave, and hopefully inducting a little more air/fuel mixture.

It isn't snake oil, but it can only be tuned for one very specific RPM. Otherwise the length of the tube has to "trombone" in and out to optimize for various RPM. It is work a bit, but not particularly practical. Formula one used nested tubes on an actuator that would shorten and lengthen with engine RPM. Tried it and abandoned it. Cost (weight, complexity, failure rate) vs benefit (small).

It sounds like this bike kit may not have a very big tube. Plus it must make the flow do a 90 degree turn each time it enters and exits the tube. Not good. If anything, this added volume in the intake runner may help to dampen pressure fluctuation and allow the carb to better flow fuel at part throttle. Don't know.

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A rather abrupt fitting on a billet manifold on the cyl head side, an aluminum u tube underseat, and a specially-crafted tube that grafts to the side of the air side of the carb.

This all was developed because Ron was wrenching on 500cc two stroke hill climb bikes, and had success there.

The specific rpm range theory would hold true though. The low-to-middle was greatly improved.

Or to put it in terms you'd understand Stamm, 2 teeth larger on the rear, 2nd gear all day, but still enough up top to do a hundred back to camp at 6 Days in the U.P.

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I think it was 189 way back when. The billet manifold is nice and shiny-and generally helps win the bench race before it starts :applause:

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bump, cause I'm interested. & I just tried a search in google with no results . (old outta business technology ?) I'll try a search in forums here .

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He has an add in the back of the JAN. 06 issue of DIRT BIKE. He has a strange looking exhaust . for sale also, I would like to see some dyno info. No website but his email is McCORD@PulseEngineering

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I did a sarech on TT & saw a little talk in Yam section . I brought it back up for grabs & not much positive feed back. If it's so good I would think most would be using. :applause:

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