Engine squelling at start up

[sboricic123]

66cc Skyhawk.
Yesterday my bike engine started up and ran fine. Today when I start it up, it has a squelling sound somewhere but quiets down after getting it up to speed. It currently has 470 km's on it and I broke it in at 24:1. I'm running it at 32:1 now. Any ideas what the squelling might be? Could it be the clutch needing adjusting?

 

[crassius]

could be clutch slipping, but have you greased the bucking bar lately?

 

[sboricic123]

Is that the bar that fits in the chain sprocket on the left side? If so, I did that today when I first noticed the squeling. After greasing it it still squelled. Once I get moving and stops or becomes quieter that I can't hear it over the engine. It does it with the clutch engaged and disengaged.

 

[2door]

Remove the right side engine access cover and look for signs that there is interference between the cover and the clutch. There have been reports of the clutch cross shaft shifting toward the right and allowing the clutch to hit the inside of the cover.

You'll also want to lubricate the gears under that cover. Dry gears won't cause the probelm you're having but they need to be lubed. Just a dab smeared on the surface of the gears will suffice. Too much grease will cause the clutch friction pads to slip.

Tom

 

[crassius]

I had one once that did that noise - looked under the clutch & one of the case bolts was loose and had ground its head off on the back of the clutch.

 

[sboricic123]

Remove the right side engine access cover and look for signs that there is interference between the cover and the clutch. There have been reports of the clutch cross shaft shifting toward the right and allowing the clutch to hit the inside of the cover.

You'll also want to lubricate the gears under that cover. Dry gears won't cause the probelm you're having but they need to be lubed. Just a dab smeared on the surface of the gears will suffice. Too much grease will cause the clutch friction pads to slip.

Tom

Well I removed the cover and didn't notice any wear. I lubed the gears as well. I took it for a spin this morning and it still squeled after checking the cover. So I thought I'd check the cylinder head bolts while I was out. After tightening them I didn't have the squel anymore at start up. When I got home I removed the head bolts, added more Loc-Tite and torqued them to 10. A few hours later I took it out again and it was fine.

 

[2door]

Typically a leaking head gasket doesn't cause a squeal but a popping or tapping sound.
Nevertheless we're glad you've found and fixed the problem. Keep a watch on those head bolts/nuts. They usually require tightening after a few heat/cool cycles. I'm assuming your "10" is in foot pounds. That's on the low end of the recommended scale. 12 would be better. If you use an inch pound wrench 120 to 140 inch pounds is what we usually recommend.

Have fun and ride safe.

Tom