Kt100/L&T clutch

I have a 4 spring wet l&t clutch that I’m having problems with. I ordered some clutch oil from cometkart sales and when I put some into my clutch the back wheels on my go kart are stiff to spin. Sometimes while spinning the back wheels, the piston moves. I’ve already cleaned it out multiple times and I’ve installed the clutch many times too. The only time the back wheels were able to move freely and fast without moving the piston was when I cleaned out the clutch and applied wd40. Every time that I turn on my engine, it revs all the way up and doesn’t stop so I have to turn it off. There’s no way of controlling the speed, as soon as I start it the engine revs at its peak.
please help

Welcome Patrick. Please add your last name to your profile

I’m guessing you’ve already ensured the throttle is closing as it should. If that is the case, then you likely have air leaking into the engine or perhaps
It’s just too lean on the low speed screw on the carburetor.

Common air leak sites include: Head, base gasket, carb/engine manifold, the carb itself and crank seals.

KT100 clutches can be finiky until you figure them out.

What’s the air gap, have you messed with the adjusters to try to increase the stall speed?

edit L&T does have all their user manuals online to help guide you

Ive already messed with the stall speed on clutch and also the low and high speed on carb

the engine runs fine without the clutch but once I install it and when I turn on the engine, the engine revs and has no idle or anything. its like if I was giving it full throttle. I have to choke it in order to stop it from accelerating and to completely shut it off.

I’m not sure what you have going on but the clutch simply can’t cause the engine to run away like that. Don’t expect it to idle. There are reasons for the engine to run away like that, usually a severe air leak. But it isn’t the clutch.

The only thing I can think of… and it’s pretty distant scenario …

A combo of worn crank seals and main bearings such that the weight of the clutch is pulling the crank down enough to allow air to leak in.

Wow, that’s a stretch

1 Like

I dont believe it is the engine because it was recently rebuild by an older guy who raced back in the day. I had the bushing on the clutch drum replaced because it seemed to be cracked and it is still doing the same thing. The piston moves very slowly when i move the back wheels and it turns the engine after maybe 3 to 5 spins on the back wheels. only time the wheels were able to move freely was when the clutch was comepletely cleaned out with wd40, and the piston wouldnt move at all. I was maybe thinking that the clutch oil’s consistency is way too thick or something but im not sure at all. The engine ran well when I removed the clutch. i was able to control the rpms and rev it as if it was in good working order when i would step on the pedal. Also there is not any vetical play on the crankshaft and all seals are new.

In my opinion it sounds like you have two issues. A clutch that is sticking so much that when you spin the back wheels will not cause an engine to run away. Do you have the crank spacer faced the correct way and is it the correct thickness. They make different crank spacers (thickness) for wet and dry clutches and also different sprocket sizes. Also what you could do is remove the clutch and make sure the friction disks “float” or have wiggle room inside the body of the clutch itself.

The engine running away sounds like a stuck throttle. Have you physically taken the air box off started it up and looked at the carb butterfly to make sure it’s not staying open after you start it?

Thanks for your help, Bryan, I will be looking at the butterfly today in the afternoon and I will also check my clutch internals for wiggle room. For the spacer, I have the flat side against the clutch drum. How do you check and measure that you have the correct thickness for the spacer? The spacer i currently have is .102" I believe

When you tighten down the starter nut it should lock the clutch to the crank, but the drum (with the sprocket on it) should still spin freely. If that’s not the case it’s usually because the spacer is the wrong thickness.

I run L&T dry clutches so my setup is a little different but i’m pretty certain the same philosophy still applies.

1 Like

Im curious as to why you want to run a wet clutch? When i raced kt100s back in the day it was a big thing to only run dry clutches.

I can’t speak for him but I ran a wet clutch in our heavy class. A wet 3 disk L&T clutch. They are bullet proof for the most part. I could run my clutch the whole season with zero issuewhile the Sr. Class was rebuilding there’s 2-3x the season. They were just a bit slower out of the whole because of the fluid.

Back when I ran karts last(2005) the wet clutch was used for pipe. Experienced can drivers ran dry. New can drivers ran wet because the extra heat handling capability was good for those learning. L and T has a manual online. It shows the air gap for the friction plates to be .030 to .035. Use a feeler gauge to measure. I think shims are available if needed. I am not sure. The gap between clutch and spacer should be .010 to .020. Again user a feeler gauge. Either one of thse too tight and clutch will not spin freely

1 Like

Hi! I had the same issue and the problem For me was the spacer. Make sure it’s oriented the correct way and grind it down on the flat side or get a thinner one on order. The last L&T I ordered, I had to reduce the width of the spacer for some reason it was too thick. It now works fine.

1 Like

So after going through everything and trying to find my problem, I found out that my my clutch has warped frictions disc, I’m not sure of this may be the cause of all of this. I also found out that the throttle cable does get stuck at times because of a slight bend it has. Does anyone know where I could buy parts for my clutch, I have a L&T 4 springs 3 disc wet clutch. I don’t believe the spacer was my problem because the clutch has enough play to where the clutch drum moves freely without grabbing. Thanks for all of the replies and help

Comet Kart Sales, https://cometkartsales.com/L-and-T-KT100-Clutches/

Heat will be the biggest source of causing problems, either excessive slippage, low oil or wrong oil.