TY250D carby issues

[cwilson]

I have picked up a TY250D that doesn't idle or run well without the choke on. can anyone recommend a bike mechanic in Sydney to get it running nice or any simple things to try I'm not up to speed on jetting etc.

[David Lahey]

The symptoms sound like the pilot jet is probably blocked. This is a fairly common problem if a bike has been sitting for a while with fuel left in the float bowl. The fuel turns into a gummy residue over time. Pilot jets have a tiny hole for the fuel to go through and so the gum blocks them very easily.
To clean it out you will need to take the bottom section off the carby.
Any motorcycle mechanic would be familiar with this issue and be able to fix it easily.

[JimsShed]

If the carby clean doesn’t fix the problem then it’s likely you have a vacuum leak. Commonly, the crankshaft seal under the magneto will need replacing. A leaking seal will cause it to run lean, hence the need to use the choke. Regardless, any Yamaha dealer can fix your problem.

[cwilson]

Thank you I have cleaned out the Carby and jets seem clear. It only dies on idle now, it revs fine when throttle is open but dies as soon as the rpm gets down to idle. Only idles with choke on any suggestions?

[David Lahey]

Have you set the idle mixture screw and set the throttle slide stop position?
Usually about 1.5 turns out from fully in for the screw and turn the slide stop screw inwards (lifts the slide) until it idles.
If there is still some junk in the pilot circuit, you will still have a problem at low throttle openings

[cwilson]

Thanks - got it idling better it must have been the pilot jet I found it finally and it was blocked - I was previously looking at the wrong jets!

[David Lahey]

Excellent