Why Right 2 Cyl. don't 'Fire Up' ?

[Locomotiveman]

1980 XS runs out A-OK..but the right 2 cylinders don't fire now when starting the bike for first 30seconds or so. I have never 'synched' the carbs but plugs look pretty good. Wuzzup guys? Locomotiveman

[BigDick]

Check if your right side petcock is plugged, the left one is for carbs 1 and 2 the right is 3 and 4, coils are 1 and 4 and then 2 and 3. Also do you have the rubber automotive fuel line or the clear lawn mower type?

[foreda]

No fire

Are the plugs firing? If plugs are firing, then fuel and air are needed for combustion.If she runs ok after you get it started, chances are a good sync will fix this problem. Did you try starting on Prime? May be a vacuum issue or petcocks not supply fuel.

[TopCatGr58]

Hey "Loco",

Are you talking about first starting it from dead cold, and using the enrichener/choke lever!? There is a small jet down inside the float bowl that is easily clogged, and it supplies the fuel for the choke/enrichener. SO..if it's clogged, it won't allow much if any fuel flow, and so you won't have much if any for starting.

Take the float bowl off and spray carb cleaner down in that tunnel you see in the edge of the bowl, and it should spray out thru that small jet. IF it doesn't, you may need to take a fine wire to press/poke it into the jet to try to open up the crud, same for the tunnel, crud can build up down there as well!
T.C.

[John]

I would be tempted to remove the bowls and check the starter (choke) orifice for blockage. That is that hole in the front edge of the bowl that that the choke pickup tube sits in. It should be open to the float bowl. It is a very small orifice, so if you attempt to clean it out, use a thin strand of copper wire to poke around. You won't distort or enlarge the orifice that way.

[Locomotiveman]

trulyXSive TopCat...The 'Right side' no-fire issue is when not started/run for a day or so. I did replace petcock rubber seals last year...good flow. I like the idea of spray or wiring out the choke orifice first. 'Synch' job is probably due. 48K and the Yamaha wrench sez she's A-OK otherwise. Locomotiveman

[Locomotiveman]

John TopCatGR58 foreda...The 'Right side' no-fire issue is when not started/run for a day or so. I did replace petcock rubber seals last year...good flow. I like the idea of spray or wiring out the carb's choke orifices first. 'Synch' job is probably due. 48K but the Yamaha wrench sez she's A-OK otherwise. Locomotiveman