Newton KT gear help

flattop1

Dawg 89
I need a starting gear for racing a KT 100 at Newton. Or a big 1/8th mile track .
My memory's failed and my notes are worse.
Thanks
Tony
 
Hey through me a bone .
A gear for a 1/5th mile .
Not worried about the piston hanging out , I'am about the rod
 
You will not get to 15,000 rpm at newton with any success. A 23/63 final drive sounds more like gearing for a 1/4 mile track.
 
It may be possible . The current standard is the jackshaft setup with a standard
2-3 disc dry clutch . Practically bullet proof . 219 or 35 your choice .
 
I turned 13,000 with my kt100 on a high bank, get off the throttle for a microsecond on entry, 1/8mi oval with 57/21 belt drive on the primary side, 35 chain/gears on a bully 3 disc with 18/66 gear combo, egt at about 1070 or so, ran right with ltd mod animals every week, spark plug always looked a tick on the rich side, never got the nerve to turn it any harder for fear of sticking it...
 
The great Don Garlets once said after red lighting, If you don't get a red light once in a while, you're not cutting it close enough"". On my dyno, without ever sticking an engine, I use to see KT EGTs at 1150 on a regular basis. Some a little lower, depends some on what fuel you run, how good your engine is. One exceptional engine I saw 1200. On a cold day I've seen higher than normal and just the opposite on hot days.
It's called tuning, and tuning is tough (Al Nunley)
The clue is; if you find a peak you're comfortable with, and you lean the top down just a little, and the temp goes down, that means you went too far. If it goes up, that's what you're looking for!
 
I agree on the EGT, its hard to remember when the air is dryer (or colder or both) the EGT should be higher since the engine is getting more air into the air/fuel mixture causing it to be leaner and subsequently making the exhaust hotter, even harder to try to comprehend that during a race and then get your mind to work with your hand to get your fingers on the carb adjuster to make the needed adjustments, but sure makes for some exciting laps on the track....
 
The great Don Garlets once said after red lighting, If you don't get a red light once in a while, you're not cutting it close enough"". On my dyno, without ever sticking an engine, I use to see KT EGTs at 1150 on a regular basis. Some a little lower, depends some on what fuel you run, how good your engine is. One exceptional engine I saw 1200. On a cold day I've seen higher than normal and just the opposite on hot days.
It's called tuning, and tuning is tough (Al Nunley)
The clue is; if you find a peak you're comfortable with, and you lean the top down just a little, and the temp goes down, that means you went too far. If it goes up, that's what you're looking for!

edit up front: Al I remember you have an issue being able to see with your eyes what you read and I spread my writing out to try to make it easier for you to read. My dry humor just told me that I also remember you having an issue being able to see with your 'mind' what you read. ... :) yes Al, I have the same issues. ... :)


Al I think I understand and agree up until maybe today just now on your advice to engage the clutch at peak torque. Today reading your post a thought hit me.

Isn't it normal for any engine because of the work it's doing when the clutch engages to drop rpm a bit? If they do then to do the work of getting going with what ever your riding be it kart, race car or everyday car, wouldn't you want to engage just above peak torque? Then when the normal slight loss of rpm occurs and you want to get up and go, you'd be at peak torque.

Otherwise if you did engage exactly at peak torque when your need to 'go' occurs you'd be below peak torque. If so, even when using a vertically mounted scale to set your clutch, when you do find the highest scale reading you'd probably want to increase spring tension some to put your start of engagement slightly above peak torque.

Seems to me in the past on here when discussing where to engage your clutch, an experience argument always came up saying to engage just above peak torque. I've never understood the why of the argument usually made but maybe this thought today is the reason experience may tell racers to do so?

Don't know for sure Al it's just all IMHO and ain't necessarily right anyway. ... :)

edit: The theory to engage at "peak torque" would still be correct, but how you get there because of the mechanics of your clutch would change.

I want to argue with myself and say the highest scale reading would still indicate a clutch set at peak torque. But now I'm thinking there probably would be two highest readings.

The first is when the engine with the clutch engaging first crosses the peak torque line while it's accelerating and you would initially see on the scales or maybe even dyno. If so wouldn't you then want to adjust the second time you would read "peak torque" to your final lockup of the clutch after 'normal' loss of get going rpm matched up with your initial peak torque reading? You'd still be matching up your engine capabilities to your clutch engagement.

Writing today I can't imagine "NOT" crossing the "peak torque" reading twice before getting maximum acceleration out of what ever your riding.

Thinking about it more the first time you cross "peak torque" you'd be accelerating and the second time the engine would actually be decelerating when you cross it and lock up occurs.

Thinking about it more wouldn't it be beneficial to cause final lockup to occur when the clutch is decelerating instead of accelerating?

I can't now imagine anything not decelerating for at least a moment, when getting going. Even if you were spinning the wheels, at the final use of maximum available grip you'd still slightly lug any engine.
 
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out of curiousity, if youre running a 9.50 final drive ratio and changed it to a 10.50 final drive ratio, approximately how many max motor rpms would you expect to pick up?
 
That would depend slightly on what was available.
If you've been racing at 11,500-12,000 then potentially 3000 rpm .
 
Assuming of course that you don't want to lose any speed.
gear change.jpg
 
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