KZ2 Kart Loses Power in Left Turns

Hey all!

Me and my friend recently bought a gokart together - A KZ2 with a TM K8 engine. We took it out on track first time today, after a couple of weeks of restoration and tweaking. Everything went surprisingly well, considering the kart is 12 years old.

The only thing that’s bothering us about the kart, which we’re both completely unable to understand why it’s happening, is that the engine completely loses power in left turns. It doesn’t stall however, it just idles and drags the kart along at low speed.
After a couple of seconds, it springs back to life again.

This happened everytime in low-speed left-hand corners, never ever turning right. In the mid-speed left turns, you could keep it from bogging down if you didn’t release the throttle completely.
Apart from that, the engine itself was working flawlessly.

We’re at a loss here. Me and my friend are both very new to the world of karting, so our experience won’t get us very far on this strange problem. We would very much appreciate all the help we can get!


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Check to make sure the axle isn’t shifting/moving and dragging on the brake.

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Perhaps see if you can replicate the problem on the stand in case tie rods or something strange are kinking fuel lines or such.

Then if it does not occur on the stand the problem can be isolated to something being affected by the grip force such as carburetor or axle

It does sound like a fuel starvation issue, for whatever reason. Very strange.

If you can’t find anything in the lines I’d see if you can borrow a carb to try and isolate, or have a carb rebuild done. Maybe something’s busted and moving about inside the carb under left turns. Just a stab in the dark though lol.

Strange one

Call or email IM-USA about it.

I just had the same issue. The needle valve in the carburetor is sticking. The needle valve that I am talking about is the one that looks like a cartoon bomb with the red tip.

On mine the “T” shaped tip was binding when it moved in and out which affected the float and fuel delivery.

John K

It might sound silly but I’ve seen this problem a few times only to find out that the drivers uniform was covering the inlets to the airbox on left hand turns.

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Sounds like a float height thing to me. First thing to do would be get the carb cleaned/rebuilt. This is doable yourself, just download a dellorto manual or if someone is around nearby that can do it have them do it.

If the floats are set too low then the fuel sloshes up the side of the float chamber and the pickup can’t get any fuel. Once you’ve slowed down enough or are going in a straight line again the fuel sloshes back down and it takes a few moments for it to work back through the system. Other less likely possibility is the fuel pump isn’t able to provide enough fuel to fill the float chamber adequately. Fuel pump rebuild is also easy, just need to buy the kit.

Beat me to it. I remember someone racing experiencing exactly that on KT100 years ago. Scratched his head several sessions before figuring it out

These ones can be a pain to resolve… Add to the list to check that the fuel pickup in the tank is in fact free to move both directions. In the past I’ve setup a gopro to video the fuel line as it leaves the tank.

The K8 is a great engine, but it’s over 20 years old I think?

Didnt want to start a new thread, but have exact same issue but ONLY hard fast right turns. Ive tried everything with the carb. Chsnged needles, jets. Cleaned out.

The only thing i never did anything to was the floats. Not sure how to check them. They do move freely but not sure how to measure heights and how to adjust.

How long has it been since you changed the sinker line in the fuel tank?

Look up IM-USA & ring them up. They’re tight with the TM factory in Italy & know TM KZs thoroughly.

Long time…that was on my list of items to change

I did pull it out 2 weeks ago and looked free and clear. Had it running perfectly fine before with the cr125. Then got a good deal on the k9b

I did today. But they didnt give much info because he wants to see it run first and what not. One of the guys actually comes to our track quite often but he wasnt there today.

Id go to IM but borders being closed doesnt help

IM has ops in Sumas, WA & in BC, so if you’re up north, you can still take it to them.

The USA site has listed emails that might help finding out how/where to meet with them.

What system are you using for feeding the carburetor on the TM?

When I ran one, the best solution was tank sinker line → fuel pump inlet → fuel pump outlet → fuel filter → tee mounted to the Nassau panel : one way leading to the tank return : one way leading back parallel to the two other lines → to the carburetor. That kept the carburetor fed with fuel at about 300mm (12") of pressure head. Satisfactory running was attained by using a #200 needle and dinking with the float height until it stopped spraying fuel out the breathers or bogging off of corners.

If you’re using the CR125 pump-around, normally the float bowl is kept full at all times, but that’s an easy system to flood.

so i have a TM K9b running the Mikuni pump. followed the steps online on how its supposed to be run, checked with other setups at track and all the same.

sinker line, comes out to fuel filter —> main pump inlet ----> out on the two ports coming to Y connector —-> going to T connector. One leads back to fuel tank other end going to carb.

My floats look crooked. One seems to be bent, thy move freely. I just ordered all new floats and few other parts for the carb. Will order new sinker line. Fuel pump is brand new, there are a few tight bends on the fuel line so i cut some longer new ones and putting a new fuel filter…

If it still doesnt work then ill set it on fire lol

I may try the longer fuel line running to the carb.

Also do the floats need to be sitting level when holding the carb upside down with float bowl off. Mine sit slightly tilted downwards. Others ive seen sit level.

Just wanted to update, i did end up fixing the bogging down in right hand turns.

I changed a few things but im 100% it was my fuel filter. When i was cr125 i never changed it then came to the k9b and never changed the fuel filter so i always had this issue. I was barely able to blow through the old filter.

I also changed my floats, made sure all my jets in the carb were clean, checked the height of the floats to make sure they were even. Everything runs awesome now!