Yamaha Dt 125 R '89 Misfires and stalls under load

[zimbobrad]

Hi peeps,

I;ve got a 1989 DT 125 R and it was running fine but just keeps on misfire when I start riding. It doesn't seem to like revving at all and after a few seconds it then just dies. It idles absolutely fine but as soon as you ride it starts to misfire and stall...

I've tried a few things to get it running properly so far;

- New spark plug, Coil, HT lead and Plug Cap

- Cleaned out the carb

- Checked for broken wires found none.

I have a few ideas to what it could be;

- Piston rings ( but not sure if this would cause the misfiring )

- Possible Blown head gasket

- Reeds need to be replaced

- The Pulser/Source Coil

Any help pointing me towards the solution would be greatly appreciated.

Thanks,

Zim

[kenDAWG]

could the mixture be wrong? have you or someone else tried to set the carb up?what colour was the end of the plug you changed or the new plug after a couple of runs?

[zimbobrad]

could the mixture be wrong? have you or someone else tried to set the carb up?what colour was the end of the plug you changed or the new plug after a couple of runs?

Hi,

I've set the mixture to my manual and like I said it idles fine but any load it dies. Currently no else has tried to set the carb up as it's at work and no one else has experience with bikes and/or carb set ups.

The plug (before replacing) was black and wet which according to my manual is oil fouling? And after trying to go for a ride the plug (new plug at this point) is wet, So I'm assuming my mixture is too rich, correct?

I think I'm going to do a wet and dry compression test with a friend to see if the piston rings are gone. Will keep the results posted.

Thanks,

Zim

[Airhead]

you should check the main jet isnt blocked