Suddenly Lost Pace/In Search of Lost Time

I had been running at the front of my club series earlier this year, picked up two wins. A few races ago, I had an incident battling for second and bent my axle. Switched to backup stiffer axle, it was no good. Got a new axle, same stiffness as the original, winning setup. I have had no pace since the crash.

I had no handling issues and later put the chassis on a table - it is straight.

The last race I went out and had no pace at all, data from my Alfaro seems to indicate that the drop-off was all over the lap. I was too slow to keep up with juniors, +2.0 seconds from my normal pace on a 50 second lap. I retired after a few laps.

I knew I was slow from a test day the Friday before the race. Over that test day I tried changing everything on the front end, track width, axle height, the changes made the chassis feel better and better, but the pace was not there. I did not feel like I had too much grip or that I was “stuck,” I pushed the rear track to 55" and did not improve. Tires are in okay condition, MG reds with 3 races on them.

I thought it might be carb or engine related, but I switched to a backup motor and did not improve. The backup motor had a fresh clutch. I had an engine builder look at both at the track, we couldn’t tell anything was off. Carbs looked okay. I had another engine builder look at the second motor afterwards, he couldn’t find anything obvious - the idle jet was a tiny bit clogged.

I was hitting redline around where I normally do, the engines did not feel that bad, apart from an inconsistent idle. My buddies said I looked slow off the corners when they were behind me, but did not notice anything different about my driving.

I have checked the chassis on a table multiple times, it is straight and scaled perfectly. Any ideas? Could the fuel be stale? It is three months old but non-ethanol.

I also checked for cracks, could not find any.

I am at a loss to explain the utter lack of pace.

Compkart 4r, LO206 385 lbs, MG Red tires.

Did you check for small cracks at seat stays etc? Remeber my margay from hell, that was an issue that made me feel like I forgot how to race or something.

It says you did but are ya 100%

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I found a crack in the powder coat on a seat stay, wire wheeled the coating away and found a nice clean intact weld. I have checked many times. Tell me about your experience or link to a thread if you have one on here. I feel the same way, like I just am slow now no matter what I do… something is fundamentally broken.

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I’d be looking harder for cracks most likely. They’re hard to find.

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I’ll look again and post anything I find that might be worth investigating. Are there any joints that are more likely than others? Seat struts?

We thought this might be a crack, so I took the coat off, but it looks fine underneath




I just checked again, only thing I see is maybe this?

I empathize, btw. Randomly losing pace without being able to pin the source is brutal to the ol ego. We work so har to achieve competence, it’s personally insulting when it goes away due to some technical thing.

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Have you been running the same set of MG reds since youve been driving slower?

I have a practice and race set, drop off has been consistent across them. It doesn’t feel like I am lacking grip.

I cant think of anything specifically to point out that can help but I will say if you had a crack you would physically feel that you cannot drive the kart normally at all. 2 seconds a lap is a lot of time, does the kart feel slow to you through corners? Is the data showing any specific area your down or is it just over the entire lap down on your previous sector times?

It feels okay balance-wise. I don’t feel as though I am having to drive differently through the corners. The drop-off is across the lap, which leads me to believe it is engine related, but I am still hitting redline.

You eliminated the engine as an issue when you tried a different engine, imo.

I dont know much about 4 stroke motors but that is your power source and from what it sounds like your just down on power. Could be bad fuel maybe. Jump in one of your friends karts and see if you can drive those any quicker

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That was my thinking as well, but I am lost at this point. Could the fuel be stale? That would cause both motors to be slow. Derek from ghost says that wouldn’t cost me that much time though.

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Two seconds on a 50 second lap is HUGE. Even an engine leaking down 15% with a blown head gasket won’t lose 2 seconds.

You don’t always physically feel a crack and you can’t always see it.

We pressurize the tubes with air and spray all over with soapy water.

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Maybe this is something beyond my ability to detect? Maybe I should just take it to a full service shop.

New axle, is it the same Compkart axle and not like a generic medium or something?

It is a like for like swap C1.5 compkart. The only difference is the previous one was cut down to 1000mm and this one is full length at 1030mm.

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Cut it. 30mm is HUGE even if you’re at the same track width.

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