Really struggling here...

Hey guys, having trouble getting my bike to run smoothly, or at all. Some back story...

Ive got a 77 xs360 with Mikuni BS38's. ive owned the bike for about two years and done fairly minor work on it, mostly just cafeing it. I usually commute about 10 minutes to work on it and never have any problems. I went on a longer ride a few weeks ago with no problems, but when i got home noticed i was getting low on oil. i did an oil changed as per usual.

I had been feeling like my air fuel ratio is off, so i also adusted that as well as changed the needle position back to the middle (i had it one click more open to account for pod filters and custom exhaust).

Anyways, since all of this i havnt been able to get the bike running smoothly. I can start it, and it will idle okay, but if i try to ride, it spits and sputters when i open the throttle at all.

since having these issues i have changed the carbs back to how they were, needle possiton back, and air fuel mix back... no luck.

Ive also had an issue with gas overflowing the float bowl and coming out of the air intake. cant figure out why, i adjusted the floats and soldered a small leak. no luck on that either.

any help is appreciated!
Thanks!!

What kind of gas do you run? Are the carbs gummed up ?

I only run clear gas in mine I had issues with an 1100 I had.........rebuilt the carbs and the bike was running great..........sits one month and ran like crap pulled the carbs and gunk everywhere..............

Have a few 400s that sat over a year.........over hte 4th they both fired right up and ran fine.........both have clear fuel in them.............

spectra said:

What kind of gas do you run? Are the carbs gummed up ?

I only run clear gas in mine I had issues with an 1100 I had.........rebuilt the carbs and the bike was running great..........sits one month and ran like crap pulled the carbs and gunk everywhere..............

Have a few 400s that sat over a year.........over hte 4th they both fired right up and ran fine.........both have clear fuel in them.............

Click to expand...

I run high octane no ethanol, cleaned the carbs multiple times, as i keep pulling them off to mess with the floats and needle.
Wondering if maybe i unlodged some gunk when i adjusted the air fuel mix as i hadnt touched it before.

You may need to go larger on your pilot and main jets.

Why would you need to change jets if the bike ever ran fine before? No.

If the carb overflow hit the plugs then the plugs may well be shorted down the porcelain from the flooding, they will likely miss a lot after that. new plugs. The fuel hitting porcelain then burns into a coating that shorts out easily, the spark takes that route instead of the gap.

You may think it is high octane with no ethanol but it might have some in it. It is cheaper for the oil companies to add octane with ethanol than it is with the standard chemicals for doing it due to the gov't subsidy on it. They commonly do it local right there too as the ethanol is pretty much kept separate from fuel until the last minute due to the problems it causes.

Here in Texas the 'high octane' is made by adding more ethanol. It's pretty much garbage fuel.

amc49 said:

Why would you need to change jets if the bike ever ran fine before? No.

If the carb overflow hit the plugs then the plugs may well be shorted down the porcelain from the flooding, they will likely miss a lot after that. new plugs. The fuel hitting porcelain then burns into a coating that shorts out easily, the spark takes that route instead of the gap.

You may think it is high octane with no ethanol but it might have some in it. It is cheaper for the oil companies to add octane with ethanol than it is with the standard chemicals for doing it due to the gov't subsidy on it. They commonly do it local right there too as the ethanol is pretty much kept separate from fuel until the last minute due to the problems it causes.

Here in Texas the 'high octane' is made by adding more ethanol. It's pretty much garbage fuel.

Click to expand...

ive got some new plugs, that would be so amazing if that was the issue. thank you,

as for the fuel, is it even that way when advertised as ethanol free? its a local gas station and all of their locations advertise ethanol free premium.
If not that, what fuel do you use?

I for one live in the D/FW metroplex, you cannot get non-ethanol fuel without going like 100 miles to do it. I would kill for the option to not use it, as I have unbuilt hot rod 2 strokes I planned on getting together before I die, they pretty much require non-ethanol fuel.

FYI, if your non eth fuel fuel comes from a common pump that switches to ethanol type too, then be aware you may get a certain small amount of the ethanol in your supposedly 'clean' fuel if the persons before you used it. Testing here showed that a single pump pumping all mixes tended to crossmix at least some, the plumbing being full of the previously used fuel.