Smoke and poping on 1980 xs1100sg

[tdsmrs]

I have a 1980 yamaha xs 1100 sg that has a 4 into 1 exhaust no other mod. have been done to my knoldge is it normal to smoke alot after it warms up i just bought it

[mason79]

how many miles?

do you know the maintenance history?

what color is the smoke, black is rich,dirty air filter?

blue is oil, stucky rings? ride it and reseat them....

i would check the compression and give everything a once over

mine blew smoke fore a while and know it seems to be ok, for now

[tdsmrs]

It had a stuck float in the number 2 carb I fixed that then when it runs for a min it starts smoking and poping smoke is black it has 18000 miles

[mason79]

pull plugs, maybe one or all are rich, how does it run? throughout the rpm range? and discribe popping, decel? acel?

[tdsmrs]

During acel. only its life a backfire in the exhaust

[TopCatGr58]

Hey Tdsmrs,

You say you fixed the stuck float. Did you happen to notice what size the main jets were while you were in there? Also, did you remove all four bowls and check the float height? Should be about 23mm. Also, had the P.O. done work on the carbs before you got it, like rejetting it since he put on the 4-1 pipes?

Many folks have reported having problems with K&L brand carb kits due to not knowing what style of pilot jets to order, and so had the wrong style which run very rich to the point of fouling the plugs, black sooty plugs, smoke, etc.!

Also, are the brass caps on the top front of the carb bodies still there? If so, you can't adjust the pilot/idle mixture screws until you remove them. I'll find the instructions I just posted on how to do that, and add a link to this reply in a minute!
T.C.

[TopCatGr58]

Just posting the instructions for removing the brass caps!

If those caps are still there, you can drill thru them just about 3/16" thick, use a small bit, and put tape up around the 3/16" point to show you where to stop, or ease up so that when you break thru you won't damage the pilot screw heads. Then screw a sheet metal screw into the cap, and use some pliers to wiggle and remove the cap and throw away!!!
T.C.