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Posted by Tfrank59
- October 15, 2018, 12:16:34 PMRob, my air box is not modified but I have done the dynojet kit and my exhaust is modified. I think it's actually a little too rich based on the way it runs and that I get this black soot coming out of the exhaust when it's cold. There are other things that lead me to believe it's not lean mainly because when I got the bike it was totally anemic and the jet kit cured that. Actually my motor runs perfectly but it does that cough thing every now and again which is more of an annoyance than anything else. As for bad gas that's a possibility of course and my last tankful I put in the ethanol free high test so we'll see if that improves things. I fill up with that like every third or fourth tankful, and especially in the cold months. I will also run some seafoam through it per one suggestion
Posted by rob f
- October 15, 2018, 10:43:38 AMSomething I found out recently playing with around with my carb, was some info from Mr Google. If your bike spits back through the airbox, the fuel mix is too lean. If it backfires through the exhaust it is too rich. Sounds like yours is too lean because it is worse cold.
I have been dicking around with my carb half the summer to gain more power. I installed a dyno jet kit and gained a tad bit. I was looking at Grampsizing the airbox but was not comfortable with the irreversable butchering of the box. Instead i invented a ram air system that had only one small screw hole drilled into the air box. Took her out for a ride and was spitting and stumbling in higher gears everytime i cracked the throttle. Came home and removed the ram air system and problem disappeared. Too much air in the fuel mix.
I am guessing that your bike is modified with different pipes,carb jets and grampsized air box? Has this problem showed up out of the blue or have you just done a recent mod? If it is outta the blue then the seafoam trick may work as you may have a plugged jet. How about water in your fuel? Could cause the same thing. If your airbox is modified, try duct taping up some of the opening and see if your problem goes away. Not a permanent fix but just a verification that it is a lean mix problem.
Rob
Posted by Pilgrim
- October 15, 2018, 09:11:25 AMAdd a big dose of SeaFoam to a full tank of gas and run it out..it will clean your fuel system. May help.
Search seafoam in the search box and see results others have had.
Posted by mittico68
- October 15, 2018, 02:26:46 AMI'm not a carb guru. And I can't help ya out.
All I can say is that sometimes it occurs to my bike, too, but it's when I try to give full throttle with the engine still cold...
Or when I try to accelerate even though the bike is ridin' at really low rpm's, in 4th or 5th gear.
Posted by Tfrank59
- October 14, 2018, 17:53:20 PMHey does anybody have like when you give it gas sometimes at an idle the thing will spit and cough for a second? And it doesn't matter if it's cold or hot but it's more apt to do it when it's cold of course. It's kind of embarrassing cuz I actually had the thing cut out on me a couple of times at an intersection when that happened. It doesn't happen that often maybe once in a 2-hour ride. You carburetor gurus what do you say? Is it a fuel-air mixture thing? I've had other bikes do it too like Honda one lungers and I never really figured out why it does it just had to live with it