fasteddie14
Member
The setup now is 21x57 by 22clutch rear is 61 gear ratio now is 7.5 good top end is the clutch gear to big need to fine happy running. engine is 13,800 rpms
Running jackshaft setup need better bottom end exiting corners
- Thread starter fasteddie14
- Start date
phantomkartracer
Member
From "Racing The Yamaha KT100-S" The rule to remember is: "Pipe for top end and gear for low end, and always gear to the pipe." Brian #89
fasteddie14
Member
We have good top end so can we adjust the flex length shorter will that also help on bottom end and will that raise exhaust temps
phantomkartracer
Member
Shorter flex moves the RPM up in range, not down. With shorter flex, you will "not" have better bottom end.
Brian #89
War Dog Racing
Member
To add on what Brian Said and shedding some light from my experience.
Shorter Flex - Improves top end (But increases EGT, if carb needles stay in the same setting)
Note- If gear is correct and flex is too short it can stick a piston if you're not on top of engine temps.
Longer Flex - Improves bottom end (Helps decrease heat/ EGT, if carb needles stay in the same setting)
Note- If gear is correct and flex is too long, you'll feel the kart running out of pull/rpm during the straightaway.
If you test flex I recommend making 1/4' changes. I say 1/8' flex changes (fine tuning) are harder to feel and see unless you have a Mychron 5 2t and can capture data with a racetrack that has the same conditions. (Not realistic most of time playing on dirt)
Shorter Flex - Improves top end (But increases EGT, if carb needles stay in the same setting)
Note- If gear is correct and flex is too short it can stick a piston if you're not on top of engine temps.
Longer Flex - Improves bottom end (Helps decrease heat/ EGT, if carb needles stay in the same setting)
Note- If gear is correct and flex is too long, you'll feel the kart running out of pull/rpm during the straightaway.
If you test flex I recommend making 1/4' changes. I say 1/8' flex changes (fine tuning) are harder to feel and see unless you have a Mychron 5 2t and can capture data with a racetrack that has the same conditions. (Not realistic most of time playing on dirt)
We are changing over to two stroke...Mag95. What engine are you working with?
deznutz
Member
Kb06?
Kansas/Oklahoma
Chris Cooper
Member
Which tracks ?
fasteddie14
Member
If making flex longer should go add 1/4 inch at a time or how do you know when to stop? From the how long for the flex lenght.
Could be your kart isn’t rolling free enough through the turns. It’s bound up. Setup is very critical on a low HP engine like a Yamaha. Your tire program could be too aggressive, or are you running treads? What other engines are you racing against? You could also have a tired engine or one that isn’t properly built. For having a user name like “Fasteddie” you’re asking a lot of basic questions. Just saying.
fasteddie14
Member
Well having that name came back in the days 1970 when I ran Mac 91B1