Clutch questions

mtbikerbob

Member
I am relatively new to karting and have been perplexed by the clutch options available for the KT100. Basically you have the dry friction clutch or a wet style friction clutch. However the higher horsepower TAG karts have a centrifugal clutch that requires almost no maintenance and seems to last longer than either style friction clutch. So why does no one offer a centrifugal clutch for the KT100? My understanding of the TAG clutch is it engages at a relatively low rpm, so its basically direct drive with the ability to start and idle on the grid without moving. Wouldn't that be ideal for the KT too? Appreciate your input and ideas.
 

sundog

Member
The 3 disk Patriot Clutch from Comet Kart Sales is excellent. You can set it up with heavy weights and light springs for a low rpm lock up if low maintenance is your goal. The TAG engines have about 3 times the HP so coming up out of a tight turn from low rpm is not a problem and believe me they have clutch problems too. Axle clutch is pretty much outlawed in asphalt sprint. It would help to know which exhaust system you have, weight of class and size of track.

Sundog
 
Back when Yamaha was popular in Australia.....there was a company called STRIKE that made a friction hub style clutch for the KT100.

We used them for a little when we tried to revive Formula Y in the Midwest. Unfortunately, they were outboard mounted as I recall and we broke a few cranks. Not sure if it was a end user related failure, or a typical design flaw for that application. It never went past a second season.

Walt is spot on with his recommendation of the Patriot. You could probably even get away with a one or two disk, depending on weight, application, and budget.
 

rainman

Premium User
The JICA class (Jr 100 cc piston port class) had a spec clutch or at least one most engines came with, low engagement, and in fact if I am not wrong it was manufactured by Hortsman since that's where I used to find parts for them. Engines like the Comer P50 and P51, Parilla Swift, etc. They engaged at low roms and I never had any issues withthem. I have run one for years without any maintenance at all on my P51 running faster laps than my older reeds on an asphalt sprint track in Spain. Crank is probably better quality an Yamahas and different taper if I am right, but very low maintenance and pulls very close to a direct drive.
 

sundog

Member
Rainman, I don't think that JICA clutch fits on a KT100. As far as cranks breaking that's part of our history too from the extra large wet clutch days which is why the third bearing support arm was developed.
 

mtbikerbob

Member
The 3 disk Patriot Clutch from Comet Kart Sales is excellent. You can set it up with heavy weights and light springs for a low rpm lock up if low maintenance is your goal. The TAG engines have about 3 times the HP so coming up out of a tight turn from low rpm is not a problem and believe me they have clutch problems too. Axle clutch is pretty much outlawed in asphalt sprint. It would help to know which exhaust system you have, weight of class and size of track.

Sundog

I run senior pipe with a L&T 3 disk and that has worked well, but the regular maintenance can be a pain. My son runs juniors with a 4 hole can, he has a Horstman 5B 2 disk. It works but i haven't been impressed with the durability of the whole thing (friction disk, bearing, basket have all had issues). Our local track is a half mile with a good mix of open and tight turns.

I guess I don't know if the adjustability is a help or hindrance.
 

gary10

Member
The higher slip results in more wear but better performance. If you put a Tag style clutch that engages below 5k on a Yamaha can and raced against guys engaging the clutch at 8600 where most makes peak torque you would be down considerably. Dry clutches are lighter/smaller diameter so they accelerate faster than wet clutches. A Yamaha pipe engages a clutch around 10k and a dry clutch will not hold up very long at that rpm so a wet clutch is used. Yamaha clutches in general are very fragile and must be driven carefully. Starting the engine early and engaging the clutch in the pits, multiple slow pace laps before a start, spinning frequently, and going off track in the grass can ruin a clutch almost instantly. If you can avoid these things the clutch will last exponentially longer.
 
The higher slip results in more wear but better performance. If you put a Tag style clutch that engages below 5k on a Yamaha can and raced against guys engaging the clutch at 8600 where most makes peak torque you would be down considerably. Dry clutches are lighter/smaller diameter so they accelerate faster than wet clutches. A Yamaha pipe engages a clutch around 10k and a dry clutch will not hold up very long at that rpm so a wet clutch is used. Yamaha clutches in general are very fragile and must be driven carefully. Starting the engine early and engaging the clutch in the pits, multiple slow pace laps before a start, spinning frequently, and going off track in the grass can ruin a clutch almost instantly. If you can avoid these things the clutch will last exponentially longer.


Spot on info right here.
I'd add that an open pipe Yami can have peak torque above 10gs.
We had one engine that peaked @ 11,200. Talk about gritting your teeth until the clutch engages. ;)
Slipping a dry clutch that long will kill it before you leave the grid.



-----
Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
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30 years of service to the karting industry
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
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