Hi Guys,
73 CT3, Just started first time in 30 years after much work. Very little exhaust. Seems to be seeping out. I'm thinking the exhaust is clogged. I'm wondering how to inspect it. I'm sure it's not as simple as running a coat hanger or a roto rooter through it. I can work on any other component of these bikes. Never dealt with exhaust.

From what I saw in the crankcase and the carburetor, there's probable a mouse nest or something in it. Nothing visible from either end.

Help!

Tsmitty

Remove what you can out of the end & see how that looks but is probably further in. Looks like there's two parts but blockage will be in the second part. Might have a spark arresting bit down in that second part but not sure. I throw mine in the log fire. But complete system idealy need burning out in a bigger fire or gas burner to get it REALY going then compreesed air to send it through. In an ideal modern world i guess ya not meant to polute things but short of buying a new old stock exhaust i doubt any chemical will clean it like burning will. Check the exhaust port too considering how bad you describe it. Here's some pics of my various problems in the last 10 years for a laugh if i can find them. Might just be links to hit.
photos.app.goo.gl/h1NbvKpgpQXVBBVg9 Yamy 100 twin LS2 right side pipe-& left much the same.
photos.app.goo.gl/3zMaSZ4Cg3JkoTXk7 Burning something Yamy landscout i think.
photos.app.goo.gl/7rkHvm8jY4UdSRUk8 RMX250 Mouse family.
Video from when i fitted a cheapy chinese carb. Poor old girl, what a a way to be woken from hibernating. Tis a "70 AT1 with a 175 top end. Plus a clean exhaust of course lol.
Here's the fitting of the new carb. Was quite a few years ago years ago now but nothing's changed--except i've got older haha.

Sorry to clog your post up with my rubbish but hoper to see yours running good sometime.







www.cmsnl.com/yamaha-ct3-1973-usa_model8420/partslist/B-03.html

So where the exhaust leaves I removed the pipe and it looks new in there. I'll take it off tommorow and check the curved end. I tore the whole engine apart so everything internal is good.

Thanks for the post!

Remove the baffle ,( there are two parts ) , run it and see if that helps .