running good then like c--p

[oldyam80sg]

I cleaned the carbs back in February and rode the bike up until 3 weeks ago.When i stopped riding the bike ran fine.Started it up last weekend and it was good.Today it would not stay running.When i rode it on the street it was good but it wont stay running without help.Could the crappy gas have something to do with it? Seafoam to help? I was supposed to go on a charity ride yesterday but it got postponed until next weekend.

[skids]

I have a G model and occasionally the one of the floats sticks shut. It must be an issue with the vitron tipped needles in the fuel valves or Yamaha wouldn't have put that bail around the float tine. If it acts up again, measure the amount of fuel in each bowl by taking out each drain plug. The measurement does not need to be very accurate, if that is the problem, the differences in the amounts will be obvious.

[JeremyL]

I had the same problems. Drove me crazy. Pulled the carbs 3 times and kept replacing more and more parts until I eventually got it really clean, I think. But my final problem was the floats. I replaced the gaskets and put new floats on with new float jets and cleaned it all really nice. Adjusted them using a metal straight edge (little 6" one) and I hope they're set right. Old floats were getting stuck and would drop a cyl and I had an oddball one that looked rough. I know you can fine tune the floats to make it richer or leaner but I was just happy to get it running on all 4 cyl reliably.

I love Seafoam and I think it's helped me out before but if it's so bad you can't enjoy a ride then it's probably bad enough that Seafoam won't help. I always tried it anyways because I hated pulling the carbs but it's usually true. It'll really help minor problems sometimes like a rough idle or flat spot and COULD break loose a big hunk of crud but more than likely cleaner won't help. But again I still try it just hoping I'll get lucky since it does often, not always, for minor problems especially when I use a lot (like 1/3 can per tank) and let it run through then shut off and sit a few days.

[oldyam80sg]

When i started it and actually rode it-was fine.I'm going to add the Seafoam and let it sit for a day and try again.Its got to be the gas.All the pipes and plugs were fine-no carbon fouled plugs.

[LoHo]

You need to get the SeaFoam into the carbs to let it work. Drain the gas from the bowls, tap the carb bank with a soft hammer to loosen float/valve sticking, and switch the tank to prime. The SeaFoam should flow in and dissolve any varnish or crud. Once it runs well enough to ride, take her for a spin. If it wasn't too dirty or having mechanical problems, all should be well.

[skids]

I love Seafoam and I think it's helped me out before but if it's so bad you can't enjoy a ride then it's probably bad enough that Seafoam won't help. .

The thing about fuel system cleaners is that they don't clean the air pilot jets or other air passages. They do what they do...

[skids]

You need to get the SeaFoam into the carbs to let it work. Drain the gas from the bowls, tap the carb bank with a soft hammer to loosen float/valve sticking, and switch the tank to prime. The SeaFoam should flow in and dissolve any varnish or crud. Once it runs well enough to ride, take her for a spin. If it wasn't too dirty or having mechanical problems, all should be well.

True statement. I have done this to "wash-out" particles that make the float valves leak.

[BA80]

I cleaned the carbs back in February and rode the bike up until 3 weeks ago.When i stopped riding the bike ran fine.Started it up last weekend and it was good.Today it would not stay running.When i rode it on the street it was good but it wont stay running without help.Could the crappy gas have something to do with it? Seafoam to help? I was supposed to go on a charity ride yesterday but it got postponed until next weekend.

How old are the plugs?

[tarzan]

Are you sure it isn't just bad gas. You mentioned that in your top post. I helped a guy a few years ago that went through his carbs and had no luck,then he borrowed a good rack from me and still had the same problem. I finally went to his house and messed with it too for a couple hours before I decided to drain and replace the gas. It ran great after that.
The kicker was that it was running great in the first place and he was low on gas.So he stopped and filled it up, and the gas he got was bad. I think it had water in it.

[oldyam80sg]

When i started the bike the last time prior to my issue,the fuel light came on.I took the gas can and went and filled it up.That is when the problem started.I finally got my registration renewed today so i started it and took it for a ride.It had no problem riding but when i slowed down,it wanted to die.I got it home and i increased the idle so now it doesn't stall.I'm thinking maybe got bad gas as there was not a problem before.I didn't get Seafoam yet but thinking i should get some dry gas.I took out the plugs and they are a light tan and pink so I'm thinking there are a lot of additives in the gas.

[BA80]

I've been having some real strange problems with mine lately too.

Misfire on take off, dying at lights, stutter. I've adjusted carbs and replaced plugs and it's not too bad now but it just doesn't seem right yet.

No apparent problems I can see though. Bike ALWAYS runs good up till about 2 weeks ago.

[oldyam80sg]

Thinking it is the crap gas.it was fine until maybe 4 weeks ago.

[BA80]

It wouldn't surprise me a bit if it was a fuel quality issue with all the other stupidness going on.

[oldyam80sg]

I took apart the carbs totally at the beginning of February/March of this year.I cleaned everything as it was a mess.I don't think the crabs were ever this clean.I use fuel filters and don't see any crud in the lines.I even cut the lines shorter today thinking that they were too long and the fuel has to travel upward.

[donebysunday]

With out Stabil blue ethanol treatment, Lucas or seafoam your ethanol gas is good for 3-6 weeks. How old was the gas when you put it in ? ? ? Flush it ! Got a fuel injected car ? Put it in the car ! But if it's really bad flush it don't use it in the car, I did but got lucky, car coughed and sputtered for 4 blocks and ran fine after the fuel injection pushed the water through. That happened at 37K ran fine and sold at 99K. By the way I would suggest the Stabil Blue Marine Ethanol treatment over the others. I'm no longer running ethanol, again I'll go 30 mi. to get good gas.