hi , bought a dna 50 just before xmas for my boy and was ok for a week or so then oil pump failed and took out crank main bearings and scored the barrel. anyway we rebuilt the engine with new crank,main bearings, crank seals, water pump repair kit and new 50 barrel and piston kit, disconnected oil pump and run it on putoline at 40 to 1, ran great for a couple of days then started to cut out after half a mile or so, sometimes 5 miles. checked fuel pump and tap all ok, fuel getting to carb. fitted extra in line filter after finding bit of dirt in float bowl. seems to loose spark when cuts out. changed plug still the same, fitted new ht coil/cdi, ht cap and replacement tested stator and still the same!!!! there is nothing left to swap or change that i can see and cant work it out!!!when ive got it going again you rev it up on the stand and it cuts in and out as if you are turning ignition switch on and off, does not feel like fueling. has got to the point where i asked 2 local bike shops to look at it and they both said go forth, didnt want to know and 1 of them has a dna 50 in the workshop with exactly the same problem and they cant work it out either. i am seriously thinking of taking it on the moors and burning it, any help or advice very much appreciated !!!! cheers.
Check the wiring behind the ignition barrel and lookout for any trapped wires between fairings etc... Also check the air gap between the pick up coil and flywheel (should be 1mm) Have you had the carburetor off to clean? worth a go .
pick up gap is ok and i did think about the ignition switch as is only thing ive not changed, was just going to bypass it with an on/ off switch just to test, thanks for your reply, cheers nick.
