Box Stock

Whats your timing?

I have marked a KT100 flywheel in 2° increments, +/-30°. We had a powered timing light. We put the engine on a dyno. We observed the timing from 10,000 to 14,500 RPM. There was no change whatsoever. No advance, no retard. It makes me wonder; is the Yamaha ignition that much better than the B&S?

Makes me wonder; is there a need for an aftermarket, high-quality, ignition system for the Briggs? One that actually maintains a precise ignition timing over the usable RPM range?
 
alvin l nunley said:
I have marked a KT100 flywheel in 2° increments, +/-30°. We had a powered timing light. We put the engine on a dyno. We observed the timing from 10,000 to 14,500 RPM. There was no change whatsoever. No advance, no retard. It makes me wonder; is the Yamaha ignition that much better than the B&S?

Makes me wonder; is there a need for an aftermarket, high-quality, ignition system for the Briggs? One that actually maintains a precise ignition timing over the usable RPM range?
Click to expand...

Did you look at the timing in the range briggs uses say, 4-8000?
Likely the Yamaha timing had retarded as far as possible already?
 
I have always heard the theory of high timing was due to the junk coils we have retard timing significantly at higher RPM.

add in the plate motors with very rich jetting and to me it still sounds like we should run high timing especially if you’re Running NKA or Florida where you can’t port the head.
 
95 shaw said:
Did you look at the timing in the range briggs uses say, 4-8000?
Likely the Yamaha timing had retarded as far as possible already?
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I suppose that's possible, but "likely"? I know it didn't change any visible amount. With a KT100, and a pipe, with a water break dyno, below 10,000 RPM, the torque curve is so steep you can't get a reading between 10,000 RPM and 4000 RPM. We used to start our pulls at 14,500 and then go down. Little different from a 4 cycle acceleration dyno. If we had performed the test with a 3 hole can, we could of got down to 8000 RPM.

Strange how you can speculate on my abilities, but I can't do the same! I get the feeling that you're doing the same thing that you accuse me of doing. It's
 
alvin l nunley said:
Strange how you can speculate on my abilities, but I can't do the same! I get the feeling that you're doing the same thing that you accuse me of doing. It's
Click to expand...

I have yet to speculate on every available thread, even after being given the proper information.

Even after being given the means to sort it out for yourself, you continue.

Non of this is rocket science, or black magic.

Simple question
Does the timing at idle remain the same as in the pull range you gave?

FWIW this is the clone section of the forum.

Briggs already offers a better quality coil that does not retard timing for their engines.

That information has been available on this forum for a long time
 
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jsf74 said:
Can we revisit this a bit. So what started the high timing theory and with all the big name builders doing this it had to be for a reason? Im sure a lot of monkey see monkey do but usually these guys have dynos and can compare data accurately. How and why did this change?
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I think it started with the Nascar plate motors, back in the day of the flathead. Of course the Nascar guys were running super high compression ratios, so it was kinda like comparing apples and aircraft carriers.
A lot of guys swore by the high timing numbers, I never had all that much luck with it, and just ran it where the motor was happiest.
 
paulkish said:
How I thunk bout it.
Think about a capital V.
At lower rpm the coil can charge during the time the magnet travels across the top of the V.
When speed increases the top of the V gets closer together because there is less time to charge the coil.
To compensate for it, the now narrower V needs leaned over some so you can start charging the coil at the same time. But you still will have less time to charge the coil.
What else can help are either have a coil with less resistance making it easier to charge up or use a stronger magnet.
Click to expand...

Ok if I can quote myself I sure can reply to myself. ... :)

here's what I propose for a solution to timing retarding

It's simple. Fact: Combined magnets increase the magnetization.
Increase the magnetic force and you can charge the coil better/sooner.

Were all into centrifugal clutches ain't we?
Simply put a tube, square, round, oval or what ever and load it with an additional or additional magnets >>>> With a spring between them<<<<<

When the flywheel spins up the magnets come together because the springs keeping them apart compress.
Whaaaa Hooo the magnetize is increased because the magnets combined and you have prevented retarding.
Now how do you look at this without thinking it's retarded? ... :)
You can control when the magnetization increases by different springs and/or changing the weight of the magnets.

no?
 
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