Hello, first time poster here. My grandfather recently passed away and gave his 1970 CT1 to my Father. It was tuned up some a buy a local motorcycle mechanic to get it in running condition but after some riding we have an oil/exhaust leak where the exhaust pipe meets the engine. See attached pictures. My dad has basic mechanical skills, and I have close to none. From what I can see it looks like it might need a new O ring to keep the seal tight. Is that the correct assumption? If so, any recommendations on O rings?

Thanks in advance!

Look at the parts diagram.. You may need #10 or #15 OR both

www.partzilla.com/catalog/yamaha/motorcycle/1970/ct1b/exhaust

Despite the mess it makes its not serious & could even come up dry after an extended road ride if its been sitting for a long time. 15 says gasket but its a strip of string like stuff the you feed in around there. Might even pay to searate the two parts to make sure it's clean of old string & start again. Talking Oring, i know my KX125 had the Oring system & worked great--so it there's a heat resistant )ring you can find it'll be easy to experiment. Pipe might not be sitting square on the the flange so not sealing good. Could just weld it up solid so long as you can get at both screws. Re-thinking my KX was around the outside of the pipe flange so different & not end on seal. Also as 'yamahahaha' said above, number 10 would be a good idea too.

from the UK.

+1 to Yamahahaha's post.

Check out the very recent thread below.

yamaha-enduros.com/index.php/forums/1968...ffler-gasket-packing