XT125r issues

[ultraculture1...]

I bought one today on the cheap, it comes fairly unloved and in need of tlc, two main issues are not idling, wont tick over and none working speedo.
I have looked on tinternt a lot and cant seem to find a definitive fix for the speedo, it seems it is a common issue yet no info on how to fix, i have zero info on screen, but all the other lights work, neutral, high/low beam etc. Should i take it off and clean it up?
Now the idling issue, i thought it may be an issue with the carb, ii thightened up the throttle cable and gave the idle adjustment screw a twist and now it will kind of idle, but i took it for a test run and it started to 'over rev'? I had to balance clutch to keep it from burning up. I may have to take off the carb eh? I would rather not as this is the first time ive tried ficing bikes and im learning as i go.
Any help would be gratefully recieved. Oh and the airbix, can i modify this to give a small performance increase or is it not worth it?
Sorry for essay, thanks once more.
Namaste.

[Suntan Sid]

Have you got any base settings for the carb, should be available in any manual?
Have you lubed the throttle cable, it might be sticking?
Get stuck into the carb give it a clean and blow out!
Have you checked for air leaks around the intake?
Get it running as standard before buggering up the air box with your Black and Decker, highly unlikely you'll see any gain in performance anyway. IMO the only performance gains will be made by shedding weight from the bike!
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