Kawi2strokes.com Forum

Joe Byrd on this board (battleax) had this idea of using a velocity stack of sorts to change the power characteristics of H1's and H2's.
viewtopic.php?f=2&t=606
I am in the middle of experimenting with another version that I am anxious for someone else to try as it is so cheap and easy.
I originally used PVC schedule 40 elbows and thought they softened the hit too much probably due to the smaller ID; have since bought some schedule 80 elbows and will try them next.

Now for something simple:
My 72 H2 with stock carbs and Denco's now has Fernco rubber plumbing connectors for 1 1/4" pipe and are 3 1/4" long.
The hit is still softened but much like Joe's post, there does seem to be more bottom and a smoother transition. Am wondering of the power is still there but spread around, and, that the loss of "coming on the pipe" confuses the butt dyno.

Since these couplers are only a few bucks a piece I thought someone else might to give it a go.
I screwed up my old pods while playing with PVC and Rube Goldberg adapters and just zip tied them on the end of the Ferncos. For a quick try, one could run it with no filters (although I can't bring myself to with all the grit on the roads here).

Be prepared, this is ugly:

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

Yes, I have outlined doing this for a long time now, years, in fact. There are many hardware store goodies that work nicely on out bikes.

If there is a positive result of X length, would it be the same if the length was added to the intake boots instead of the bell side?

John

Dave,
I had originally included your name in this as you had mentioned this years ago but figured no one would remember.
Do you have any basic advice as to where to start with length of runner and whether straight verse curved makes a difference?
Also curious to know how to determine how much air filter is required.

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

All right you non-experimenting, TV watching, I'm content with the way things are, don't need better, varmints.
No one into experimenting for cheap any more?
No one here want to tell me it's a crap idea?
Are you guys feeling well; not even a decent insult?
Don't you want to make your bikes better? (OK, you total restore guys get a hall pass on this one)
I think some of you have gone soft (and no blue pill is going to fix that)

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There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

Hey, if it works for you, then hey, cool! I would think most guys like the "rush", or maybe it's a bit too "shade tree" looking for some......

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Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

I was planing to try it, but am going to play with some reeds instead.

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If it surges, that's normal, upshift.

I'm just looking for butt dyno confirmation
Much less hit but really feels stronger in the 2500 to 4000 band
Find myself barely revving the bike and after a few easy shifts I'm at 50 mph.

Jim, Cody is running reeds with a ported motor and big carbs and reports his extended runners were a welcome addition.

JA, was going to refine the design with some polished tubes (maybe with hiddes foam) once I was satisfied that the additional bottom end didn't adversely effect the top end.
Would be interested to see you try them on a road race course and compare lap times some day.

_________________
There are only two types of motor sport racing:
Nitro and everything else
(Sometimes referred to as fast and slow)

_________________
Twist the throttle, tilt the horizon, and have a great time. What triples are all about...........

Watch out, folks, the dreaded, and useless dyno info is coming.

Yup, distance is the key in the inlet system, and a curvature isn't the best to do, but, it doesn't hurt all that much. I will state that a nice, well designed air box, with a still air area, K&N filter inside it would be a lot nicer than those household washing sponges, but, the best thing is their length extentions, those work.

As far as length, the ONLY dyno that will tell you conclusively what does and doesn't work is the "seat of the pants dyno". That is the dyno that was used for the statement about the helping in the 2.500 to 4,000 rpm range.

Please don't get me wrong, a properly addressed and used dyno is a FANTASTIC development tool for things like balancing factors and crankshaft weight mass inertia, porting, head shape, exhaust pipe configurati0on development, but, the end game is strictly sitting/riding on the seat.