Hi,

My sons dt has started having problems starting .new plug fitted ,not the best spark I've seen but should be enough. I've stripped the carb and cleaned the pilot and main jets .shes firing on the starter but won't catch and pick up . If I keep her spinning long enough with the throttle open she will catch and run. As soon as you let the revs die she cuts out . Any ideas as I'm running out of obvious ones before I think about big uns like crank seals

Leave the plug out overnight. In the morning tip a little 2 stroke oil down the hole and with the plug still out turn it over a couple of times. With a clean plug back it, try and start it again.

I would also recheck and set the carb, a different plug and fix any issues with a weak spark. Normally seals will have the bike running at high revs and then slowly coming down until the engine dies. If it is reving high and not returning to idle (especially when hot) then I would say the crank seals are shot.

You may want to say hello in the new members section. First post questions are often ignored. There are a lot of 2 stroke lovers and, I would say, experts on the forum.

Thanks, I've just picked a new plug cap for it and have noticed it actually starts better with the side stand up . Can't really figure that out yet as it should only affect the running if you put it in gear with the stand down . I'll bypass the side stand anyway for now , also tried a different cdi and doesn't make any difference . I'll have a play with the mixture settings

The sidestand switch is just an earth so the bike should spark or not depending on this.

You can wash out the bore with trying to start the bike so the compression may need the oil like I posted earlier.