Sprint st Serging help please!!!!!!!!!

[Gunner]

I have an issue with my sprint st, Hoping someone can help. Out for first ride of year, 13 degrees celcius. Six to seven miles, all was fine. Stopped for 20 minutes, went to start and it wouldn't hold an idle. Managed to keep it running with revs up and get it into gear, if i backed off on throttle it would want to stall, with throttle loaded, it felt fine, as soon as i back off it jerks and wants to stall. While driving constant speed, it's chugging like it's out of fuel. felt like a real sloppy chain.. new plugs, new gas. Took out plugs and they were black, changed back to old ones, went out again, did it again after I stopped for gas after 20 minutes. Not sure where to go from here. Any ideas? Thanks RCR

[dolson]

You need to list the year of bike before others can help.

[Croak]

Gunner, you got some good answers on that other forum you asked the same misspelled question.

[Gunner]

the bike is a 2006 sprint st, sorry about the spelling, more worried about the issue at hand. The frustrating part is i have a trip planned in 2 weeks. I will pull thing apart again and make sure i dont have a bad connection or a bad wire. seems to be after i stop the issue starts. Thanks

[oldndumb]

Long version.

In no particular order.

Malfunctioning tank vent line. Could be pinched or the tip over valve stuck closed. That condition should cause a whoosh sound when opening the tank after running a few miles. Would not be direct cause for plug fouling.

MAP sensor not connected. This condition should throw a MIL.

Throttle body hose disconnected. Same fault as MAP sensor.

Coolant temp sensor, Stepper malfunction, TPS, Inlet air temp sensor, Ambient temp sensor. Any one of these could cause a running problem but they will also throw a MIL.

Since you do not have a MIL, the sensors are working.

Troubleshooting should then go to ensuring that all adjustments are correct. These are Throttle Body Balance,TPS adjust, Idle Speed Control Stepper adjust. A reset adaptation would be necessary after performing any of these. You would not expect these items to go out of spec over the winter, but you would need to baseline them to be able to do valid trouble shooting. BTW, what heat range plugs are you using?

Short version.

Pull tank and air box, reinstall everything correctly, do another road test. Bad gas could cause your problems. Also verify that your MIL light is working.

[Gunner]

Thanks for the info Oldndumb, MIL=engine fault light? It has been on since this issue started, Changed fluid,plugs(stock) and oil. light came on and when i went for a shake down ride it all went to hell. had it apart 4 times looking for the wire i missed and found none. Airbox off again!

bikes goin into dealer tuesday, I surrender! the triumph gods have won! I'll let u guys know. thanks for all the tips..Much appreciated!!! Gunner