Maintenance & Technical > KX500 Original

Exhaust valve timing..?

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John:
Mun,

Got it! These are nice graphs, thanks Mun!

Looks like the exhaust valves are starting to open at 4500RPM's and are fully open at 5500RPM's. There goes my theory of "never half-open"...

When you did these tests, did you increase the rews quick och slowly?

Do you agree with my interpetation?

//John

doordie:
You can use a extern spring attached between KIPS-wheel and  cylinder, it?s very easy to "TEST" different springrates and see what?s happens.
After that can you test with preloaded stock spring or buy
a KX250 spring. :wink:
My own test will be with my third kx500 to get so much torque as possible,
spreaded for so long rpm-range as possible. :twisted:
(fourstrokes beware)

Recept:  :idea:  
Gnarly pipe with extension part
Powerblade
D-shaped carb.
Flywheel weight
High compression(wide squish)
Low exhaustport
Reshaped scavening ports
Modified KIPS


//doordie

YUNGGUNNAZ:
great.now we rolling.we'll say openning 4500.fully open @5500.now if we open it earlier @oh 3800 say will the power now spread more smoothly, at a  greater efficently, maybe peaking a little more hp.
doordie, 1.5" added to head pipe should help torgue on gnarly.

mun:

--- Quote from: YUNGGUNNAZ ---
where did the other 2. hp go from previous graph?
--- End quote ---

Previous is with 490 main and this is with 500 main.
We start Slechten pipe with 500 main (57hp), what i use on tarmack. It's badly too rich on inertia dyno!!! (You can't find best jetting on inertia dyno! It has not enough braking to burning all fuel that you neet on track.)
Then 480 (65hp) and 460 (66hp), which was best of tested. But more smaller can be better, no time. Then MuN-pipe, start 490 (72hp) > 500 (71hp), no other :(. Powervalve testing (i quess again) we make with MuN-pipe and 500 main jet.
I remember that "powervalve OFF" mixture was very very rich.
This dynoing happend almost 5 years since and i don't remember all exactly. Some of those difference can be of dynos tolerances. Motor temp and pipe temp (it's most importing), ...



--- Quote from: John ---Looks like the exhaust valves are starting to open at 4500RPM's and are fully open at 5500RPM's. There goes my theory of "never half-open"...
When you did these tests, did you increase the rews quick och slowly?
Do you agree with my interpetation?
//John
--- End quote ---

John, your theory about "never half-open" is right. Please don't shut me, because i don't remember sure. If someone can take cover plastic of cylinder, so that KIPS moving arms is seeing. Raise rpm slovly and check what arms making. I'm so sick than i can't do now that. I last start my KX summer 2004 :(.
This dyno was PekkaP's Fuchs-dyno, http://www.pekkap.fi/fuchs.htm. That is acceleration, or inertia dyno. Pekka raised rpm slowly to 4000 and then wide open. We dynoing KX only one evening. If you want better results you need own dyno and eat and sleep in dyno room :).

Remember: My old -86 KX500 have KIPS only side exhausts, not in main exhaust.

There all rest dyno graphs:

doordie:
Mun,you have a different carburator (mikuni 40mm) than we other so the jetting is not the same.
I?m up to 205 mainjet with ovalbored Kehin (39mm) at the same hp(70+) as you. :wink:
Hope you will get better soon Markku! :cry:
This test with KIPS should be done on a water or oil braked dyno for best result.

//doordie

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