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Sorry for the novel. In case there's something I missed, wanted to get it all out there.
I got my bike last spring. It had been sitting outdoors for several years and needed some serious love:
Rusty tank was cleaned and epoxied, carbs were professionally cleaned and tuned. That got it running although still not all that well with serious hesitation before it would really take off and truly awful running before it was 100% warmed up. The air box snorkel was missing so that was replaced and a few tanks with some fuel system cleaner (Seafoam?) seemed to get it running better although it still had no power when not fully warm and it had a tiny lug at high speed (65+ mph).
This winter, I did the shims, replaced both the carb and air box boots and sealed the air box along with a new filter. The new filter may have gotten a little too much oil (I used motor oil) but I let it sit for a couple days, wrung out the excess that collected at the bottom and sopped up the pooled oil so it shouldn't have been too bad. Also cleaned and put new seals in the leaking timing chain tensioner.
At that point, it ran 90% better. It maybe seemed to lose a little bit of power at WOT and still had that slight lug at highway speeds. I assumed it needed to have the carbs vacuum synched after messing with the valves and boots but haven't gotten that done yet.
So here's the deal: A couple days ago I topped it off with fuel after the ride home and added a quarter cup of Marvel Mystery Oil to the fuel. My dad swears by the stuff and the internet doesn't seem to have anything bad to say about it so why not? After reading up on the lug here at GSR, I took the cover off the gas cap and blasted it out with some WD-40 although there was no visible gunk anyway. Apparently I had topped it off a little too high as the next day, there was a small pool under the bike. I cleaned it up and noticed it was a little oily and wasn't really evaporating like gasoline should, probably because of the MMO that was poured in on top of the gas. There didn't appear to be any on the bike so I assumed (and still do assume) that it drained cleanly out the overflow tube and caused no problems.
Only there are problems. On the next ride, it ran absolutely flawlessly until it got up to highway speeds and then started with that same lug. Only this time, it quickly went from a slight lug to a bad lug and then got so bad it could barely maintain speed. At 55 and below, the lug goes away. At hard acceleration or higher cruising speeds, it comes back.
It sounds like a fuel problem and the MMO makes me think some dirt or whatever got knocked loose by the solvent and plugged up a choke point, maybe at the petcock or fuel line but more likely a jet. The fuel line appears to be old so I ordered a new OEM one and will replace the newer-looking vacuum line as well just for the heck of it. I'll also pull the petcock and look it over. If that doesn't help, is it time to pull apart the carbs or is there some other thing that could be the issue?
Again, sorry for the novel.
I got my bike last spring. It had been sitting outdoors for several years and needed some serious love:
Rusty tank was cleaned and epoxied, carbs were professionally cleaned and tuned. That got it running although still not all that well with serious hesitation before it would really take off and truly awful running before it was 100% warmed up. The air box snorkel was missing so that was replaced and a few tanks with some fuel system cleaner (Seafoam?) seemed to get it running better although it still had no power when not fully warm and it had a tiny lug at high speed (65+ mph).
This winter, I did the shims, replaced both the carb and air box boots and sealed the air box along with a new filter. The new filter may have gotten a little too much oil (I used motor oil) but I let it sit for a couple days, wrung out the excess that collected at the bottom and sopped up the pooled oil so it shouldn't have been too bad. Also cleaned and put new seals in the leaking timing chain tensioner.
At that point, it ran 90% better. It maybe seemed to lose a little bit of power at WOT and still had that slight lug at highway speeds. I assumed it needed to have the carbs vacuum synched after messing with the valves and boots but haven't gotten that done yet.
So here's the deal: A couple days ago I topped it off with fuel after the ride home and added a quarter cup of Marvel Mystery Oil to the fuel. My dad swears by the stuff and the internet doesn't seem to have anything bad to say about it so why not? After reading up on the lug here at GSR, I took the cover off the gas cap and blasted it out with some WD-40 although there was no visible gunk anyway. Apparently I had topped it off a little too high as the next day, there was a small pool under the bike. I cleaned it up and noticed it was a little oily and wasn't really evaporating like gasoline should, probably because of the MMO that was poured in on top of the gas. There didn't appear to be any on the bike so I assumed (and still do assume) that it drained cleanly out the overflow tube and caused no problems.
Only there are problems. On the next ride, it ran absolutely flawlessly until it got up to highway speeds and then started with that same lug. Only this time, it quickly went from a slight lug to a bad lug and then got so bad it could barely maintain speed. At 55 and below, the lug goes away. At hard acceleration or higher cruising speeds, it comes back.
It sounds like a fuel problem and the MMO makes me think some dirt or whatever got knocked loose by the solvent and plugged up a choke point, maybe at the petcock or fuel line but more likely a jet. The fuel line appears to be old so I ordered a new OEM one and will replace the newer-looking vacuum line as well just for the heck of it. I'll also pull the petcock and look it over. If that doesn't help, is it time to pull apart the carbs or is there some other thing that could be the issue?
Again, sorry for the novel.
