1100 idle problems

[Matt Padgham]

This problem could be linked to other issues so I'm looking to see what you guys think.
Bike is a 98 1100 GS, no cat, with CO2 pot.
I cannot get the bike to idle above about 900rpm, the brass bypass screws are closed, if I open them the bike runs rougher and eventually stalls.
Used a local garage to test CO2 output and the bike is running lean (0.6-0.8%), adjusting the CO2 pot made no difference to CO2 percentage. Could this be linked with low idle?
Would I be able to increase the idle by adjusting LEFT hand throttle body cable 1st then the Right as when synching throttle bodies.
I've sprayed WD40 etc around rubber seals on throttle bodies and there appears to be no leak. I've pulled off the CO2 pot and this seems to be working, can get a change in resistance as the screw is turned etc.
Am I missing something obvious?!

 

[Stewart H]

I would check the TPS voltage, also try removing the BBSs and cleaning them then doing a good synch using the BBss at idle and the cable slack adjusters at higher RPMs.
Stewart

 

[Benjah]

Sorry can you please explain what BBs are?

 

[Stewart H]

Sorry can you please explain what BBs are?

Big Brass Screws

Stewart

 

[kostas_patra]

clean your bbs with carb cleaner, like stew said. it won't do you harm, exept it it falls over painted surface, but it won't fix your problem

check collars and manifolds for air leaks, it might fix your problem, but i don't think so

try measuring tps vostage with a multimeter and you will find the root of your problem. make some marks before moving tps, then set it at 370mv and then do a proper throttle body synchr as steward suggested and 99% you will be ok

 

[Matt Padgham]

I've checked tps and adjusted it very slightly to richen mixture, now at 371mv had been 368mv. Cleaned and synched BB's and now have an idle that I'm far happier with - approx 1000rpm.
When i got CO2 output checked it is now up to 1%, still lean, when i turned the potentiometer I cannot get the CO2 output to go up or down! I've checked the potentiometer and with a multimeter across pins 2&3 and get a resistance variation so I assume it's ok. Are they known to fail even if a change in resistance occurs?!
Any more suggestions guys?
Thanks for previous replies.

 

[Stewart H]

I've checked tps and adjusted it very slightly to richen mixture, now at 371mv had been 368mv. Cleaned and synched BB's and now have an idle that I'm far happier with - approx 1000rpm.
When i got CO2 output checked it is now up to 1%, still lean, when i turned the potentiometer I cannot get the CO2 output to go up or down! I've checked the potentiometer and with a multimeter across pins 2&3 and get a resistance variation so I assume it's ok. Are they known to fail even if a change in resistance occurs?!
Any more suggestions guys?
Thanks for previous replies.

I bought a used one from motorworks to try, I believe they will do a sale or return on used bits if you are fault finding it does sound like yours is working though.
Stewart