81 G1 exhaust question

[bisquit476]

Ok, so it finally cooled down to the point that I feel like working on the cart. Can't get the cart to run right/if at all. So, from what I've read from you fine folks here about the G1 gas, sometimes it needs the muffler BBQ, so I thought I'd try that first to see what happens. So off comes the muffler, and I, out of curiosity look in the exhaust of the engine. I see a shaft, but that is it. It has screw holes in the shaft which peaks my interest. I bring my happy butt onto the computer and into the Yamaha parts page, and lo and behold, the IPC shows a butterfly valve in the exhaust. Mine is missing. Now, I'm going to ask a stupid question (because I don't know) but will having that butterfly valve missing cause the cart not to run? I have 120psi compression, so I'm scratching my head, wouldn't my compression be low if the exhaust shutoff (butterfly valve) was missing. The shaft has a lot of play to it also. Anybody's thoughts are appreciated.

[ic746]

Hi 476 and welcome to them crazy G1's, I have had 3 of them and now have 2 a 81 and a 82 model. I took the butterfly's valves clean out of mine and they run fine. Now I do pre mix and dont run a oil tank on either one of mine. I hear the butterfly is for when idoling so it runs the right amount of oil into the engine, I really dont know but both of mine run fine without them.
Now if your muffler is clogged up it will run good after you BBQ it good and all that mess runs out into the fire. I BBQ'ed both of mine and they run strong afterwards. Years of golf coarses and running at slow speeds builds up oil in the muffler until it clogs it up.
Good luck.
Calvin

[bisquit476]

Thanks Calvin,

I wasn't sure about the butterfly, so now it's back to bbq'ing the muffler and seeing if that helps.

Thanks again,
Bill