mikuni carby idle to high

[davespitty]

Mikuni carby idling to high with idle screw right out wtf is going on (on a brand new lifan 125)

 

[my67xr]

is the cable seated properly at both ends?
is the cable adjuster on the throttle (at the handlebars) backed off all the way?

otherwise i'd be looking for a vacuum leak.
have you fitted the boot to seal the top of the carby to the cable?
do you have the plastic insulator fitted between the carby and manifold?

 

[davespitty]

yeah checked everything found a air leak fixed that got the plastic spacer on o rings good new gaskit
the throtle body wont get all the way down and cant find a siplifyed way of tuning the air mixture screw

 

[davespitty]

and the idle is pretty aratic reves up (2500) for 3-5 secs and then back down to idle

 

[Hillz]

its actually a fakuni (Fake mikuni) & can be very hard if not impossible to get right once they have started to show such symtoms

 

[davespitty]

Got it idling perfect just got a flat spot soon after take off from what ive seen on youtube just cant find any where that can tell me about the adjustment of the centre needle in the throtle body there are 4 different settings u set wit the cerclip cant find any info about its use and adjustment

 

[my67xr]

http://scootrs.com/tech.cfm?tip=tunecarb#e

http://www.mikuni.com/pdf/vmmanual.pdf

 

[davespitty]

Cheers mate

 

[davespitty]

Fixed lifted the main jet needle to its highest setting and runs like a dream