Following up on my post from awhile ago

[mgp214]

Hey guys, I just wanted to follow up on the problem I had signed up to ask about last winter: http://honda-cb750-s.456789.n3.nabble.com/Wildly-fluctuating-warm-up-rpm-td4055136.html
Due to moving and other distractions I wasn't able to solve it until just recently, and I wanted to post about it because I can't stand it when people post problems and never say what the solution was!

Turns out it was a vacuum leak! Now that it's warmer and I was able to more easily start the bike, I was able to pinpoint the leak to the throttle shaft on the carbs. Apparently, soaking the carbs in cleaner without removing these was a bad decision as it washed the oil out of the felt and created a pretty bad leak. I went ahead and replaced the felt seals and soaked them in white lithium grease and BAM leak plugged!

Thanks again for the help!

[rich]

Thanks for the update. That's good to know. I'll bet a lot of people try to clean the carbs without splitting the rack.

[Re-run]

I guess I never soak my carbs. Manual clean only, for me. I guess if I ever start doing ultrasonic, then I will split them. Still, that is good to know.

[mgp214]

I did actually split the rack (the throttle shafts are individual to allow syncing), and I mostly disassembled them—I didn't want to soak any gaskets. I guess I didn't remove the throttle shafts because I didn't realize there was anything in there that would be harmed by soaking in a solvent bath. oops!

[icerigger]

Interesting! None of the posts or available documents I've seen even mention removing the throttle shafts. Both SeanG and Mike Nixon leave them in.