When I start my bike when it's cold, the left side cylinder doesn't fire. It is definitely the carburetor as I had my mechanic confirm this. Once the motor warms, the carb kicks in and the left side starts firing. Then the bike runs great. Iv'e had the carb apart several times (stripped down to everything but disassembling the butterfly valve and shaft) and soaked in cleaner, blown out with compressed air, thin flexible wires run through all the ports as best as possible and eyeballed very carefully. Everything seems in order. Any Ideas?
You've most likely got a lean condition. What's causing it is anybody's guess, but here are the most likely in the order you ought to check....
Choke Issues
@ Blocked choke orifice in the bottom of the L float bowl.
@ Choke butterfly valves not closing together
Carb Issues
@ Leaking intake hose at carb-to-head
@ Carb spigot loose in cyl head
@ Dis-similar needle heights in slide
@ carbs way out of sync
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
I would vote for the blocked choke orifice in the bottom of the float bowl, as Wobbly suggested. I have seen this more than once. I actually solved that issue for a rider one time at a camp out. I used the tiny wire from a bread twist tie and a small quantity of Maker's Mark to clear the orifice in the bottom of the float bowl. I filled the enricher's take up column in the float bowl with a few drops of Maker's and poked the tiny wire into the bottom of the choke feed column until the whiskey dribbled out and in to the bottom of the main chamber. Problem solved. I was a stone blue genius that day and it makes for a great story. If you decide to try this with a can of spray carb cleaner, be sure to wear your safety glasses. Don't ask me how I know this.
former Airmarshal, IL.
Many thanks to Wobbly and 8053. Indeed, it was the jet at the bottom of the float bowl. I removed the brass jet for closer inspection, and though it was open, there was a slight restriction which I opened up with a wire. In my previous dismantling of the carb I hadn't actually removed that part as I assumed it was ok as I could see daylight through it and blow air through it. Well, there you go.
Thanks, again,
blacktail
No prob. After rebuilding hundreds of English, Italian and Japanese carbs, I almost missed that strangely located jet in the bottom of the bowl.
That jet gets clogged when fuel is left in the carbs over the winter or other long storage, which is why I advise removal of the float bowls during that time.
Owning an old Airhead is easy.
Keeping an old Airhead running great is the true test.
Advertisement
