kt100 plug? and flex ?

oscarlee

New member
whats the best plug to use KT100 pipe class dirt 1/5 mile 14,600 rpm and how often replace it have used NKG, Autolite 51 and 2652(something close to this #). also Ran 13,400 with 9 1/4 flex CRE 8, 66 gear add flex or go to 68?
 
whats the best plug to use KT100 pipe class dirt 1/5 mile 14,600 rpm and how often replace it have used NKG, Autolite 51 and 2652(something close to this #). also Ran 13,400 with 9 1/4 flex CRE 8, 66 gear add flex or go to 68?
I ran a few Yamaha races back in the day, but it was a long time ago and I don’t remember the plug number. I do remember it was an Autolight, retracted gap, three-quarter inch reach and the coldest in that type. The fuel was premium leaded with 1 quart of castor to 5 gallons of gas.
Have you checked the compression pressure with a good gauge. Our Yamaha’s ran best with about 160 PSI pressure.
I’ve been told I’m wrong about this but, compression is the Holy Grail.
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.
 
Jack look back at the for sale section nippindenso w31en plugs for sale by the box of 10 or by the case. $30 for box of ten got my order in the guy had like 5000 plugs. Page 3 or 4 for sale section
 
thanks guys, so to get more rpm increase flex or add couple of teeth?
it has been my experience, testing pipes on the dyno, that all pipes have an ideal header length. Once you find the ideal, making a change greater than a quarter inch either way, longer or shorter, gives less power everywhere. Longer for low-end, shorter for high-end.
You can put more teeth on the axle, and as long as you pick up about 200 RPM for each tooth, you'll be going the same miles per hour on the top. The 200 RPM is a "rule of thumb". That number could change some depending on the gear ratio. Tell me what gear ratio you're running and how higher the rpm, and I can give you a more exact number.
 
Alvin here are the numbers
if you had given me the primary and secondary gear sets it would make this a little bit easier.
Trying to find the right gear ratio for you, is like throwing darts in the dark. Too many variables. My 1st thought would be to turn the engine titer. But the track layout and the grip all come into that. How the carb is set up? What type of plug? What fuel? Just knowing the compression of the engine would help. A good engine, with a good gauge, (Pep Boys doesn't sell a good one) should pump about 160 PSI.
Tuning is tough!! (Al Nunley)
 
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