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Answer to question about new pipe

Posted: Mon Aug 19, 2013 12:31 pm
by admin
Bullfrog - 08/01/08 at 4:36pm

Well . . . sort of an answer. ;)
But let me start with the "marketing hype" -- "Captain Eddie wins his class @ Washougal with new pipe!" That would make a good headline right? However the text of the imaginary article would probably mention that I was the only entry in my class . . . so its not quite so cool as the head line sounds.
Still, the pipe did seem to run well!
OK. Now for some real information. Both of the test pipes are complete. Also the necessary bracketry to test the pipes with a shorty silencer for the track and with a full (modern) spark arrestor/silencer for ISDT RR and such use.
Testing has been planned since the final week before Hodaka Days, with the intent of selecting the best pipe for "always keep the rubber side down MX use" (meaning "this thing better have some grunt, cuz I don't know what fanning the clutch means MX use") and Enduro type riding. Unfortunately, other important life factors keep getting in the way of actually doing the testing.
The pipe which is currently on the machine is a high, right side unit. It tucked in really nicely . . . and I THINK (<-- that's a BIG "I think") it runs better than the original '70's era aftermarket pipe it was "reverse engineered from". However, since I have pronounced at least one test pipe to be a great improvement prior to actual data gathering . . . and then found out that it just plain wasn't better . . . I have GOT to do the testing before making any new pronouncements. Having said that, since the pipe on the machine has the advantage of the final cone going all the way down to the proper stinger diameter AND having a decent length of stinger AND having a modern (low restriction) shorty silencer AND having a much better internal flow profile right at the exhaust manifold than the original pipe - it should run better (assuming I got the cones "right").
The second pipe was reverse engineered from the Combat Wombat pipe but was built as a high, right side pipe also. I haven't had a chance to run this one at all . . . and it is the one with the biggest "mystery factor". Did I get the cone dimensions right? Since the pipe is so long, will the extra bends required to fit the pipe to the machine knock down the performance? If it doesn't run as well as the stock CW pipe . . . which of the above factors needs correcting? Dontchaluv a good mystery?
Chehalis is coming up shortly . . . I'm hoping to get the testing done before then, but we shall see.
So, as useless as it is - that is the latest information on pipe development. Please be patient, but please stay tuned.
Ed

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sachs175 - 08/01/08 at 5:33pm

Ed,
Thanks, Thanks a bunch.
If either work well I would like the specs. Your using the stock combat piston port engine as a test bed and and a good RR pipe we could use that was quiet would be worth its weight in gold.
Given the information is not top 8) secret could you go into where you got or how you made the turning vanes up on your RR bike please. A picture would be great. The more i delve into this subject the more benefit it looks like they would add to stock engines from the time. Flat slides like the Lectron may have a similar effect on air flow as the vanes.
John D.

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Bullfrog - 08/01/08 at 6:50pm

Hmmmm, "weight in gold" . . . I might have to build a few of 'em! (out of heavier gauge than normal sheet steel ;) !!)
Did you mean tuning vanes? ie flow straightening vanes/plates in the carb throat?
Sorry, but I can't respond on the topic for a while because several rather tightly scheduled activities are shouldering in - and I can't seem to convince the clock to slow down. (preparing for a trip to meet up with our exchange student of 15 years ago for camping & fishing in Central OR, getting ready for Chehalis . . . and someone let the secret out of the bag that I run a little aviation accessory business and sales are running 50+% ahead of last year at this time).
But I can say that a flow straightening plate at the half throttle position has been a very good thing on my scooter with stock 28mm carb. I have vanes on both sides of the slide. Sorry there is no time for more comment.
Ed

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eicho1 - 08/01/08 at 11:30pm

Hi Ed,
I am also interested in your pipe testing. I need a pipe for my RR Wombat.
Speaking of the ISDT RR, isn't about time for rumor and hype to begin?
Mark

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sachs175 - 08/02/08 at 8:18pm

Ed,
I think your using something like the Scary Fast Power now and Power Now plus tuning vanes? I somehow got the idea you had also added a turning vane to the elbow in the air boot.
It would change the curve in the boot into 2 D shaped openings instead of a single O at the 90 deg bend . From what i can find out the Vane would be thin like the tune vanes but curve around the 90, centered in the middle of the O. The D shape is supposed to flow a lot more efficiently than the O around curves and corners. Finding pictures on this subject has proved to be hard. Seeing how one was built would help a great deal in finding the right materials on the first try.
Just trying to keep my R&D down to none or the very minimum Ed. Asking a lot of seemingly silly questions has saved me a lot of time and mistakes over the years .
Thanks for the work on a pipe Ed. It will help folks a lot in the end.
John D.

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Bullfrog - 08/02/08 at 8:25pm

I saw that post in one of your threads about air boxes which mentioned the "D" section turns. The concept is in the back of my head...but I've gotta finish the pipe first.

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