What do I need to know about micro/mini swift

So just picked up the kiddos new kart to practice for next year. He can’t move up yet but want to get him behind the wheel with more power and more weight. So I got a new otk with a micro swift currently. Locally we only run mini with no micro class so he will practice micro and move to mini when I think he has a good handle with the speed. What do I need to know about the swift engine.

I’ve found the Swift engines to be very reliable and robust. If you’re at all familiar with a KA100 or other IAME motors then everything will feel/work similar as well.

The biggest issue I see people having is that the motor can be finicky to start where it can be easy to flood. If your son has “happy feet” like mine and other kids where they want to stomp on the gas while pushing the starter button then this is where you’ll see kids/parents panicking on the grid when their kart doesn’t want to start.

My advice for starting is that you need to completely choke the air box off with your hand for cold starts, do not use the throttle. Since your son won’t be familiar with this it’s important to warm the kart on the stand before going out to drive or get on the grid. Once warm, just push the start button but NO THROTTLE. If you can follow that then it’ll be a breeze.

When you’re first starting you’re not going to be tuning the thing competitively so shoot for EGTs in the 900-1000 range and just make sure it’s not 4-cycling down the straights and max RPM 14k-14.5k. When you get more competitive then push those to 1100EGT and up to 15,500 for shorter/tighter tracks with longer straights as needed.

Carb- kit every 2-2.5hrs, re-torque the head 1 hour after rebuild, keep the bendix clean if buildup happens, and clean/grease the clutch after every race or practice day.

If you’re getting competitive then top ends could be necessary in as little as 5hrs, but if it’s practice time and mid-pack just keep going as long as there aren’t issues. 10-15hrs can be done in lower stress scenarios.

Have fun!


Awesome. And yeah I found out about the choking already when getting it fired. And yeah I was just treating it like my ka.

I had heard much longer between rebuilds. So that’s good to know. For now this is just a practice motor. So no stress there. And I’ll eventually get a second motor to aid in rebuild schedule.

I appreciate all the other info. And can’t wait to see his reaction moving up from a comer kid kart.

These kids pumping the throttle like a madman and then fouling out the engine on the grid drives me nuts. And there’s always a few dads going into a full panic attack on the grid because of it.

1 Like

I cant even keep my kid’s foot off the gas when I am pulling the string on his 4 cycle…

I have found a quick pinch on the big toe usually reminds him enough. He then gives me the “sorry dad” eyes and shoulder shrug :slight_smile:

1 Like

I can relate. Sitting on grid shouting “Jerry!!!, starter!!!”

Guess I’m lucky. I have the opposite problem. I can’t usually get him to use the throttle when I want him to in grid.

We created a rule. Visor up only do what I say. Visor down it’s switch to grid steward.

But he is still 5. So I’m sure it will eventually switch away from that as he gets older.

What Chris said, but I try to keep the EGT a little lower.

The only times I had problems on the grid was when I didn’t warm on the stand. If it does flood, you can pull the hose from the carb to the engine and crank until the fuel spits out and the engine makes an attempt to start. Then reconnect the hose and try again.

Keep the battery charged. It may sound like it will fire up, but it won’t. We started with a smaller battery and upgraded rather quickly.

After a carb kit or engine swap, pull the airbox and cover the carb with your hand until fuel comes out. It will be get things flowing even faster.

Hope this helps!

1 Like

From my experience when we ran the Mini Swift (and now are in KA100), is that the Swift is just a mini KA. The biggest things to remember, is as you adjust the needles, a small turn does a lot when tuning, so don’t go crazy with your adjustments, no need to do more than 1/16th at most.

Secondly, as mentioned above, is choking the motor to start. That is the biggest error I see people doing when their motor won’t start, they try choking it more, which in turns causes them to actually flood the motor. On a typical club day, you may only need to choke it for the first start of the day. Always start it in the pit before the grid, and first attempt try without choking. If it doesn’t start, then try a small amount of choke and it should start. If you get into this habit, you’ll never need to choke it on the grid. Just don’t over choke it.

As far as rebuilds, they are robust little engines. The last Swift we ran had 20 hours on the bottom end and 2 on the top end when we sold it, and the person I sold it to put another 20 hours on it before sending in for a rebuild. Just before it was sent in, they were setting track records with it, even with all the hours on it. The builder said the motor was in great shape when he took it apart, and said everything looked great. We always ran 8 oz. to 1 gallon.

Also, I know your son is still learning on it, but the target is to keep the low RPMs above 7500 if possible, but under 15000. That’s the range the motor works best in. If I am not mistaken, the micro restrictor will cause the motor to drop 500-750 rpm on the top end, but we never ran it as a micro.

1 Like