Rough throttle

[Widgeteye]

Let me see if I can explain this one.   

The idle is a little rough.
When I ride around town at slow speed there is a little bit of surging at constant throttle, in other words when the bike catches up to the throttle and is running at constant speed there seems to be a little surge, it's not something I feel but something I hear. Doing slight deceleration is rough rather than the smooth transition from constant speed to slowing down it is rough. When sitting parked and holding the throttle open it surges. But at highway speeds when under load it runs fine. Acceleration is fine.

When I bought the bike it came with after market pipes, the ones with all the seperate pipes being straight thru. It also had the after market needle kit. I removed the a/m pipes and put the stock back on (I don't like all that noise when driving a thousand miles), I also adjusted the a/m needles back to stock specs. It ran fine for about 4 years then this spring  after sitting all winter it came out of the garage with this condition.

I drove it from Amarillo to New Mexico and as I got into New Mexico it started running so rough and blowing black smoke that I pulled over to the side of the road and re-adjusted the needles. That cured the problem for the New Mexico trip except now it's doing it again. And worse.

I don't think it's the needles but I could be wrong. I finally found the stock needles and am going to re-install them today. But like I say I don't think this is a needle problem. It acts like some thing is either leaking or out of adjustment.  I checked all the vacuum lines and tank filters. All OK. I also installed new plugs, although the old ones were in good shape.

Anyone have any ideas? Would those flexible parts that hold the needles cause this if they are leaking??

Thanks
Larry

[Ricky-D]

I'd put the stock stuff back and then look at what's going on.  Some of it could be attributed to the gasoline you use, "ethanol enriched" or whatever, it changes from day to day and gas station to gas station.

The black smoke could be from a stuck float in one of your carburetors. A passing episode. Watch out for a hydrolock occurence.

If it ran good for four years I wouldn't think all of a sudden when things change, that it would be anything electrical related.

[Widgeteye]

Well I replaced the stock needles and still have the same problem. I also noticed that when I hold the throttle on at a constant RPM parked, and then ease the choke on, the RPM's increase significantly, but the surging doesn't stop. I am really suspecting a vacuum leak, maybe I missed something when I checked all the vacuum lines before. Any other ideas in the meantime? 


Thanks

[Momz]

Yep......do a complete desmog to eliminate any chance of vacuum leaks.
Get some "Seafoam" or "Techron" gas additive and run half a bottle with a full tank of GASOLINE, not E85 or anthing with an ethanol blend.

Hope that does the trick!

[bigvalkriefan]

May be dirty low speed jets. Use a whole bottle of seafoam or techron in the tank and see if that helps.

[R J]

Let me see if I can explain this one.   

The idle is a little rough.
When I ride around town at slow speed there is a little bit of surging at constant throttle, in other words when the bike catches up to the throttle and is running at constant speed there seems to be a little surge, it's not something I feel but something I hear. Doing slight deceleration is rough rather than the smooth transition from constant speed to slowing down it is rough. When sitting parked and holding the throttle open it surges. But at highway speeds when under load it runs fine. Acceleration is fine.

When I bought the bike it came with after market pipes, the ones with all the seperate pipes being straight thru. It also had the after market needle kit. I removed the a/m pipes and put the stock back on (I don't like all that noise when driving a thousand miles), I also adjusted the a/m needles back to stock specs. It ran fine for about 4 years then this spring  after sitting all winter it came out of the garage with this condition.

I drove it from Amarillo to New Mexico and as I got into New Mexico it started running so rough and blowing black smoke that I pulled over to the side of the road and re-adjusted the needles. That cured the problem for the New Mexico trip except now it's doing it again. And worse.

I don't think it's the needles but I could be wrong. I finally found the stock needles and am going to re-install them today. But like I say I don't think this is a needle problem. It acts like some thing is either leaking or out of adjustment.  I checked all the vacuum lines and tank filters. All OK. I also installed new plugs, although the old ones were in good shape.

Anyone have any ideas? Would those flexible parts that hold the needles cause this if they are leaking??

Thanks
Larry

Larry, when ya parked it for the winter did you treat the gas in the tank and run it long enough to get the solution in the carbs?

It sounds like your gas might have lacquered up on ya.  Seafoam might take it out, try a full can in a full tank of fuel and see if it clears up.  If it acts like it might of helped it, add a 2nd can of Seafoam to another tank of fuel.    If it don't clear up now, it is time to pull the carb bank and do some cleaning on the inside of the carbs, both sets of jets.

[DeathWishBikerDude]

Try some better gas.