LO206 started making an odd noise

Hello Braintrust!

This Saturday, I went to the track to get in some practice laps prior to the OSKCS series starting up. I felt like my kart was running normally and actually seemed pretty strong compared to others on the track. However, in session 4 after a few laps, I started hearing this new noise. It sounded like a high pitch rattle or a buzzy sound. It was definitely coming from my right hand side and sounded like it was coming from the engine. I slowed down and brought it back into the pits. Here are some things I noticed:

  • The noise started during session 4 of the day and a few laps into the session.

  • I have not heard this sound before running my LO206.

  • Sounded like it was on the right side of me coming from the engine area.

  • The engine ran totally fine while the sound was being made. No loss of power or throttle response was felt.

  • It did not change pitch or the nature of the sound whether I was full throttle, slow speed or idling.

  • I took it back to my pit spot and started it on the stand. I could not get the sound to start again. I let the engine warm up for 5 minutes or so (and it had just came off the track). Ran and sounded totally normal on the stand.

  • The clutch is a brand new Hilliard Fury which I installed prior to this practice day.

  • The chain is a brand new EK Silver Pro and the sprocket is a brand new Rocket Sprocket split.

  • I did an oil change with the same amount and oil type as what was in it, just prior to this practice day. I checked the plugs and caps which were all snug and in place.

You can actually hear it in my GoPro video of the session which you can find here: OSKCS Practice - 3/18/23 - New Track Clockwise - Practice 4 - YouTube The link starts around where it is the most evident and continues through when I bring it into the pits and it is just idling.

For the life of me, I can’t figure out what it could be. I checked all external bolts on the engine and confirmed they were all snug. I checked the clutch drive shaft bolt and that is torqued correctly. The chain is not rubbing on any stays or the chain guard. Sprocket bolts are all tight. Engine mount is tight. Spark plug looks normal. Fuel was brand new ethanol free purchased that morning.

Perhaps against better judgement, after checking everything I could think of in the pits and not finding anything, I went back out for another full session. Sure enough, the sound started again a few laps into the session however, the engine was running totally normal and I did not feel any change in power or revs. So, I just stayed out and nothing seemed to happen for the whole session.

Do any of you have any idea as to what this might be? I really don’t want to blow anything up but am at a loss of what it could be that happens as the engine warms (ostensibly) but also does not impact the performance of the engine? It sounds really bad, so I’d like to fix something if it needs fixing.

Make sure your clutch is assembled right and installed correctly.

It is. That is the first thing I checked. Also, the noise was happening whether I was WOT, going slow or at idle (clutch disengaged) without any change to the pitch or nature of the sound. That is why I am not thinking it is the clutch.

Is it the upper heat shield over the top of the cylinder? It is only held on by one tiny screw on the clutch side of the engine.

At our track, we call that the @Matt_Geist special. He’s too lazy to fix and all his engines rattle like that.

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I’ve had a similar sound, I never figured it out and it didn’t seem to affect performance, but went away when I changed clutches so I assumed it was clutch related.

So what’s your racing record you two? who is winning the epic battle for middle aged dominance? You guys do pretty good throwing shade at each other, I hope the on track action is equally prickly.

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lol, I wish it was more crazy, but I would say he has the overall edge by quite a large margin. Maybe 2 to 1 his wins vs mine. I will never not throw it in his face when I do beat him, though.

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Middle aged? Wowwwww…

I’m older than they are… :grimacing:

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Interesting idea! I do know that plate is a bit loose on mine. It flexes around and can be shifted slightly. I wouldnt say the bolt/screw is loose though. I’ll press on that if I ever hear it happen again. That would be awesome if it was the cause lol!

Were you using a Hilliard clutch? This was my first day with one after replacing an old Stinger that came with the engine.

If it’s not the plate mentioned, take a look at the outer plate on the clutch. I’ve had them be off center and they rub the drum. Has a similar sound.

Typically happened on an older clutch.

I’ve had noises from my 206 twice. Once was the aforementioned heat shield, the little bolt had fallen out. The other time, it was the starter “legs” (I don’t know what they’re actually called), the white things that pop out and into the cup when you pull the starter cord. Mine weren’t retracting and made a dinging noise the whole way around the track.

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Yes! That’s a good one too!

If you’re using the oil grease plate thing it could be that, sometimes the little key on it shears pretty quick and it just rattles around in there and makes noise. We always pull them out, you really should be pulling your clutch to clean and inspect fairly regularly anyhow so you can clean out any grease or chain lube then.

Hilliard flame, yes.

This is the one I was going to reference, that little pull cord ding tends to come on after its fully up to temp and completely randomly.

What should I be looking for in order to diagnose this?

Pull cord ding is typically 1-10 HZ while youre driving, the sheild rattle is constant and changes pitch with rpm on the stand. Pull cord cant do much, it’lld come and go as it wants to. Shield you can put a new screw in

2 wins to his 1 when we aren’t in the same class*** just want to make sure we all know the details here

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