ty 175 wont run & will run?

[uk steve]

Hi again i got my ty 175 running today after a rebore she fired up on the third kick and ran fine for a minute then started to back fire which it did before the rebore so i put in a new condencer and set the points at .040mm this stopped the back fire but makes the bike hard to start.tighter the points easier to start but i get a exhaust back fire and it dies.i gave it a run around the yard it pulled like a train with the points set at .040 ran like it should great idel speed then after five minute it wanted to cut out so i put on the choke and it was ok again then put choke in and it died help the wife will kill me many penny's wasted she said?

[David Lahey]

It sounds like there is a restriction to fuel flow causing the fuel level in the float bowl to go too low. Likely causes are blockage of the fuel tank vent line or a restriction in the fuel flow path. You can test for both these by disconnecting the fuel hose from the carbu and running fuel into a container. The flow stream should start strong and stay strong till the tank empties.
The way you are setting the ignition timing is dodgy. The gap when fully open does need to be approximately 0.4mm as you have said, but more important is that the points start to open at the correct position of the piston relative to the top of its stroke.
Its a bit of a story how to set the timing and you may have it close already so one step at a time.

[uk steve]

thanks dave i will fit a new 6m fule line and new points on monday.Now if i measure 1.8mm before TDC is this the correct point for the points to start to open. can i gauge it here or do i just look for the break in the circuit at the measure of 1.8m from TDC.Thanks your agreat help as always.can you email me at [email protected] so i can foward my pics.i re sized them as you said but i cant up load them to the site. i have only a 49.kbps slow connection this is a problem @ times with up loads thanks again

[David Lahey]

I'm not sure what you are asking about the setting of the timing. There are many ways to get the timing right. Using an ohmmeter, light bulb or buzzer across the points is fine. The important thing is that the points open at the right piston position.
You say that you are fitting a new fuel line. The fuel line is usually not a problem for fuel flow problems. Likely spots are the filter inside the fuel tank above the fuel tap, any filter in the fuel line, and the fuel tank venting system.
Yes I'll send an email to that address.
Regards
David