Cylinder #1 is 'cold'-- Help!

[cajun31]

Thanks for detailed steps in bench testing the carbs, Ray. I'm glad these pages are archived, as I will use the bench test one point if needed. Now-- an update. I ran the bike for a while at 4K RPM, again, but for a longer period of time, as per Bikerphil's suggestion. The #1 cylinder seemed to be firing as per usual after a time. It was up to temp, in comparison to the other cylinders, so I road tested it. It seems to be running normally now. Is it possible that there was a piece of crud that worked its way through the carb? That is my only explanation. If anyone has a thought, that would be great. Many thanks to all who suggested different approaches to address my issue. I will road test again tomorrow, as the weather is supposed to be nice again. Thanks again, guys!

Glad to see you are getting it resolved. Seems that the pilot circuit was or may still be suffering from crud in there somewhere. The ride and extended rpms may have helped. I would suggest pouring about a half a can of seafoam in your tank and start and run the bike long enough to get it in the carbs. Let it sit like that overnight then go for a good ride and top the tank off with ethanol free gas if it is available to you. No one ever asked that question of you. What type of gas is available to you? If you have ethanol free gas available, always make sure to run the ethanol gas out and fill up with ethanol free before parking the bike for the winter. You also want to shut the petcocks off and run the bike until it quits. I also drain the carb bowls before parking for the winter months. By the way I would still not rule out replacing, or at minimum checking that pilot jet in the number 1 carb.

[bikerphil]

Yep, if you're using fuel that contains ethanol, it won't take long for it to work it's evil ways. Pilot circuit has the smallest passages so it is the first to go.

[MarkD]

Thanks, guys. I do have access to ethanol-free gas here in town. I use Star-Ton gas treatment, but I should start using non-ethanol gas. I've never had a problem with my winterizing method, but then again, I've never started riding so late in the year, I usually get her on the road in the Spring. Thanks for your help, I really appreciate it. Cheers!

[Socer4m]

HI Mark, glad it seems to be ok,,,,maybe I missed it in the thread, BUT,,,,it could be a hanging float that kept the needle stuck closed, that finally worked free. If there was spark, the hanging, stuck float stops all gas from flowing leading to no firing, thus no heat on exhaust from ignition,,,,anyway if it was a stuck float usually rapping on the side of the carbs can free it up. The fix is to see what caused the float to stick, usually bowl gasket not trimmed, or float out of alignment...Ride On,,,Mike in S.DIego and Pa,,,

[MarkD]

Thanks, Mike. That's possibly what happened. Seems all good so far, but another road test today will be proof positive.

[LAB3]

The only other thing I can think of that hasn't already been addressed is a hung slide.

[DiverRay]

If you have ethanol free gas available, please use it! That is ALL I put in my '79 for the past 4 years and I've not had any problems. I do use Sta-Bil in the last two or three tanks, and that keeps it going for my five month sleep time. In California it is not available, and even a six week park would bring problems.

[MarkD]

Okay-- Road Test #2, and cylinder fires as normal. Bike runs pretty well, although yesterday and today, will not idle, stalls at low RPMs. This could be due to some adjustment I may have goofed up on the cable, or it could be a cleaning issue. I could pull the bank again, clean all carbs, and reinstall. Season is pretty much over here, anyways the temps are coming down tomorrow. Any thoughts are appreciated. Thanks, again, all.

[Socer4m]

check your fuel filters, hopefully clean,,,maybe pull the plugs and check condition, ,,,add a can of carb cleaner and some stabil for the season off...run it a bit and see how it runs. If no improvement, at least you have a small project to clean carbs over the layoff. These bikes usually need a higher rpm at idle anyway, unless everything is dead on perfect,,,,I keep my idle up as I am lazy at stoplights and its easier to get rolling again...Mike in S.Diego and Pa

[MarkD]

Hi again Lab3, Yup, checked slide , one of the first things, and no hangs, or slow response. Did pull plugs after. Road Test#2, and all look as they should. So far, I'm happy with everything, except trouble at idling, so I will clean all carbs before putting her to bed.

[oldyam80sg]

I will take the carbs off my 80 SG after riding it to my storage unit next week and remove the battery and put the bike up on wooden boards to get it off the concrete floor. The carbs will be cleaned during the winter months.

[bikerphil]

Here's what ethanol can do to your carbs in just 3 months. This is in the very high humidity of a Florida summer, probably not as bad anywhere else. Of course the pilot jets were plugged.

[DEEBS11]

The alcohol level in today's fuel is hydroscopic. It loves water. Water resides underneath gasoline when separated. Carburetors are the lowest point of the fuel system. This is why stabilizers are used to keep the water from separating from the gasoline and destroying the carbs with oxidation. I always stabilize the fuel in my motorcycles and power equipment, run until the mixture reaches the carbs, and then drain the carb for long term storage. When it's time to operate the machine, I open the carb drain, then open the petcock to flush any possible remnants out of the carb. Close the drain screws and run the machine. I have been doing this for over 40 years without a problem on the over 60 motorcycles I have owned and restored during that time.

[DiverRay]

I'm lucky living in Idaho. I can buy non-ethanol gas at most Chevron stations here. It's the only thing I run in my bike and yard tools. I do put Sta-Bil in every can I fill, so I don't need to worry about how long between uses. Springtime is usually two pulls son the push mower, and about 5 seconds at most of cranking on the bike and riding mower.

[MarkD]

Good posts, guys. I use Star- Tron for winter storage. Definitely will use non-ethanol gas from now on as well. Never had a problem with winterizing before , over 50 years of riding. I think it was crap in a passage or jet.