SR 125 stalling from idle when throttle opened.

[devonjive]

Hi,

I have recently got a Yamaha SR 125 Custom (2002 model). The bike is in lovely condition but has recently started cutting out if I open the throttle quickly from idle (hot and cold). I took it for a good long run today, stopping and starting occasionally and the problem still persists.

Any suggestions would be great to hear!!

Many thanks,

Tom

[Airhead]

Tom, does it work ok if you give it some choke?

if it does, you may need to strip and clean the carb, check the main jet and pilot jet are totally clean. If you use carb cleaner aerosol, keep it away from O rings and other rubber parts.

[barkwindjammer]

Welcome to the nut-house Tom

(Devon-jive, what must that look like?)

it just keeps gettin better !

[matt taylor]

I had the same problem with my '99.

Stripped the carb ,

took the jets out,

checked all the orings..

put it all back together after a good clean.....

Tightened the pilot screw till LIGHTLY seated, then unscrewed 1 and a half turns.

Set the idle mixture right once bike was running.

Checked the air filter hoses and MANIFOLD to the head for leaks (these can be temp fixed with electrical tape quite nicely)

Re-lubricated the throttle cable

cleaned the plug and checked the gap just to be sure (0.6-0.7mm)

Could be worth you changing the throttle needle seating position (theres notches in the needle which seat on a circlip right at the top of the carb)

[devonjive]

Hi Matt,

I have just stripped the carb out to fine it squeaky clean even still ran air through all the jet holes etc. Bike still has same problem!! Plug has a good spark but I will get a new one tomorrow. Checked all the hoses etc. and cant see anything amiss. If this was a car i would look to check the ignition timing but I have no idea how to do that or even if you can on the SR!!!

This is very frustrating! Still, when I get the new plug tomorrow I will also get a tiny little screwdriver to play with the mixture while the bike is running. Sadly I odint have one small enough and dont really fancy taking the carb off every 5 seconds!!

Thanks for your help,

Tom

[2 Wheels]

Welcome Tom to the YOC

You have now joined the rest of us in the mad house !

Have you done anything to the air box or the exhaust ???

Sounds like a main jet or power jet pipe is blocked.