C51 Kid Kart racing - WHy is my kid's engine so much slower?

ZeroClient

New member
My 6-year old is having the time of his life out there! He has actually won 3x 1st place trophies and is having soo much fun in doing so. He thinks he is a professional racecar driver, "Its what I do, dad!" Oh the joy!

So, this past weekend, he did wonderfully. His lap times are significantly consistent and his level of errors is very low. We had a great time and we're very proud of his accomplishments. We're doing this also with very little outside help as the track has low Comer Kid Kart attendance, and is mostly 4-stroke track.

Then another C50 Kid Kar showed up and really surprised me. Although my son won 1st place in the race, I wanted to have a better understanding of what the heck was 'up' with this other kid's speed and his C50 engine.

SO, the other kid's father said he just had his C50 rebuilt and freshened up. I noticed at the grid that his kid's engine idle was highly erratic with a very high idle. The kid had to hold the brake to keep the kart from moving forward meaning his idle was so high that his clutch was engaging. I did peer down at this kid's idle screw but it didn't really seem to be screwed in more than my kids. Maybe twice the idle speed of my son's kart. They had some trouble keeping the engine running too. All the while my kid's kart engine was idling rock stable at about 2400rpm; this other kart was struggling at probably 4000rpm idle and it died twice in staging.

Then at the starting line I watched closely. Green flag and the gas pedals went down at the same time. Then I say to myself, what the hell??? The other kid's kart takes off from the stop like a bat out of hell compared to my son's C51. I mean, by turn #1 my son was already about 30 feet behind his contender, and this kid was keeping up with the LO206 Kid Kart (Class was put together). I mean, no way driver skill was involved here. They both put the pedal down at the same time. It was obvious the kart was faster. Then around the track the other kid was gaining more and more distance. Maybe he was a better driver? I don't know. The other kid's qualifying lap time was about 3~4 seconds faster than my kids. Then around the front straight they both pass me and I can tell the other kid's kart must have been reaching closer to 11,000rpm. Maybe more? The engine pitch was quite a bit lower on my kid's kart. At the end of the race my kid's kart engine indicated a peak rpm of 9600rpm on the tiny tach.

Now, I said my kid won the race, and he did. The reason being, this other kid who was going a lot faster was not consistent. He spun out twice, and the second time his engine stalled and a corner worker had to run and pull the cord 4 times to get it re-started. His father said that always seems to happen when kid lets off the gas coming to a stop. My kid cruised on past and made about a 100' lead and took the win, but the other kid ended up only being just behind mine cross the finish; meaning the other kid made up the gap in less than 2 laps.


So, whats up here? To the best of my ability, we are totally legal with gearing, engine, carb, 87 octane per track rules, etc.

Is someone cheating?
Gearing?
Engine seals? (This sounds like a strong possibility with the extra RPM and stalling at idle?)
Engine porting?
Clutch?

This made me think more. Maybe I should check and set my ignition timing on my engine. Maybe do a leak-down test of my own?
 
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Jimbo

A trial w/o witnesses is like racin w/o tech
He may have just spent a boat load of money to have it refreshed / blueprinted by a professional.
If you have not had this done to your Comer get used to what happened or spend less money and put a 206 on his kart.
You will spend less money buying a 206 than you will having your Comer blueprinted by someone that knows how to make them fast.
 

flattop1

Dawg 89
YUP . Blueprinted or outlaw engine both cost big money . Check Bergfelt Racing .
The complete 206 package will be less dollars and at six years old your almost aged out of the comer class .
Your engine is fine , there engine is 1,500 .
 

ZeroClient

New member
ok so more information. The dad did mention they used Ceramic bearings - but now what I read about class and engine restriction, Ceramic engine bearings are not legal? Guess we got duped!

BUT WE WON ANYWAYS so. ?
 
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OVALTECH1

Premium User
Do you have to run the pill in your carb? A lot of places require it very few run it. You should all be on an 89 rear gear. There is power to be had in getting these blueprinted as well as take off speed to be had in cutting the clutch a bit to lighten it up. What we learned and you now know.... perfect lines, tire prepped right on the edge of grip and slip so to not bog it down and momentum momentum momentum. Be smooth and you will be fast!
 

1fasttiller

Member
Is there any tech at this track? Maybe the dad knew there wasn't and put an outlaw motor on. Obviously it didn't matter and was too much for the kids talent level anyway. Thats the bad thing about karting and racing in general, there will always be someone with an unlimited budget willing to spend thousands to get the $10 trophy but as I've witnessed, only about 1% of them have the talent to go with it. We pull up to the races in my truck, one chassis and 2 sets of tires and outrun karts every weekend that spend 10X as much. Its a quick way to make enemies especially when they pay to tear you down and find you are 100% legal :)
 

ZeroClient

New member
The track does have tech but its one guy who also does the announcements. He doesn't unbolt anything really. I think they're checking moreso for safety than anything else. For the main races they re-tech usually the top 5 karts. Thing is though, they're not really looking much at the 2-stroke engines from what I can tell. They do look for security tags on the LO206, and of course they are looking at tires and chassis safety. I think they gloss over the kid kart stuff.
 

flattop1

Dawg 89
In all honesty , you do not really want full tech . they will disassemble your engine , not often will they reassemble it, if ever .
Do not forget you are there for fun . winning is a bonus .
Stressing over who is cheating will make ya go bald .
Keep doing what you are and enjoy .
 

Jogreene29

New member
Not cheating. $299.95 blueprint package and blue printed carb. Also have light brakes and sprocket. Figured I was pretty open and even showed you how I took out some rolling resistance. My son has a year’s head start in racing. 4-5 seconds a lap comes from seat time.

He didn’t spin out twice, he stalled twice in same corner, (which is why I’m searching this forum) Seems to stall halfway through most sessions. Tried multiple fueling tricks with longer lines, in line filter, New tank and valve, cap is properly vented. Always stalls on lefts hand turns about 3 minutes in. Stall is pretty abrupt coming off corner. He has pumped the pedal and saved it a few times on video. I have had some success when I run a freshly cleaned carb. Running castor 927 at 8 oz to gallon. Any help is appreciated.
 

ZeroClient

New member
As I mentioned at the track, I thought you might have leaking engine seals the way it was idling very high and a bit erratic. I've seen this happen a lot on 2-strokes with failed crank seals. Hard starting, bouncing around, loss/gain in power, eraticness. And yes, it would allow more engine air in, and possibly go faster but the tune could be falling dead-flat when off the throttle due to mixture problems. It could be going way lean at WOT, and way rich when off the throttle; which would foul a plug and stall, or the opposite --> lean to mis-fire and stall.

Its easy to pressure test +5psi, and then -5in/hg vacuum. Needs to holder as long as possible. Spray engine seals & gaskets with water mixed with 3 drops dish detergent. Any small leak should bubble obviously.
 

Kartiac Arrest

Comer 51 Engine Victim
Your clutch shoes...do they have a lot of meat on them? If they do. Sand them down and leave a little meat on them. That would help you on your start.

We had legal engines and could get a start like an l206. It takes practice and you need to keep clutch engagement speeds up. It is probably the driver and not the engine.
 

Kartiac Arrest

Comer 51 Engine Victim
Not cheating. $299.95 blueprint package and blue printed carb. Also have light brakes and sprocket. Figured I was pretty open and even showed you how I took out some rolling resistance. My son has a year’s head start in racing. 4-5 seconds a lap comes from seat time.

He didn’t spin out twice, he stalled twice in same corner, (which is why I’m searching this forum) Seems to stall halfway through most sessions. Tried multiple fueling tricks with longer lines, in line filter, New tank and valve, cap is properly vented. Always stalls on lefts hand turns about 3 minutes in. Stall is pretty abrupt coming off corner. He has pumped the pedal and saved it a few times on video. I have had some success when I run a freshly cleaned carb. Running castor 927 at 8 oz to gallon. Any help is appreciated.
Replace the fuel needle. Anytime they form a ridge toss them. Don't ask me why or how. It just fixes the issue. Makes no sense. Lol.
 

Kartiac Arrest

Comer 51 Engine Victim
ok so more information. The dad did mention they used Ceramic bearings - but now what I read about class and engine restriction, Ceramic engine bearings are not legal? Guess we got duped!

BUT WE WON ANYWAYS so. ?
Ceramic bearings on his axle and wheels which is legal. Not likely in his engine.
 
You all seem to mention right and left hand turns, so I will assume sprint racing. A decent Comer will turn 11k, the real expensive ones will turn over 12k while being WKA legal. Get into that Bergfelt stuff and you will be broke and illegal. Just get a LO206 and work on your driver.
 

Kartiac Arrest

Comer 51 Engine Victim
You all seem to mention right and left hand turns, so I will assume sprint racing. A decent Comer will turn 11k, the real expensive ones will turn over 12k while being WKA legal. Get into that Bergfelt stuff and you will be broke and illegal. Just get a LO206 and work on your driver.
I had cheap comers that ran well at 11800+
:)
 
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