a little advice


Gday Im a newbie to this forum I fitted a ddm dom pipe drove it around the oval a few times it slowed down and died like it ran out of fuel.now it wont start it has spark compression pushes thumb away,can you take the carb of without havn to replace the gaskets.
Thanks for the input Timmah it wasnt the plug I cooked the piston it over heated and fried it self DAMN THE DRY GRASS I know now to pull the cover of and get all the sh!t out..
hey Fritz, if you cooked up the piston, its more likely was the result of running lean, now these motors can overheat, and it will sap power as it gets hotter.
but in most cases the heat wont cause the piston/ring to crap out.
dying out from overheating is the least likely cause of a dead motor.

do you have damage to the piston. if im correct in thinking it was a lean tuneing issue, you ll likely have damage on teh exhaust side of the piston, just under the ring and it will be to the right side of the exhaust port.
on they cylinder that right bottom side of the exhaust port will also be pretty messed up looking.

Any pics of the damage?
Thanks Timmah I'll get get a pic up soon for you to hav a look at wat you described is pretty much spoton the piston is scored on the exh side.It was still set at factory turns so it should hav been rich I thought?correct me if wrong.Ive put a new topend on since then no problems so far 28.5 topend dom 8000 spring rr speed gears how many turns out is safest to run for hard bashing turning screws in is leaning fuel mixtures.
the 1 1/2 out on H and 1 1/4 out on L for the stock 23cc settings ARE typically rich, but not always. an air leak will make even the richest settings seem Lean!!

for a 28.5 with A DDM Dominator, i would start out at 1 5/8 ( or 1 3/4 ) out on the High needle, and 1 1/2 out on the low needle. it may be a female dog to start as the l may be fairly rich. so you may need to tweek the low back from 1 1/2 to get it to start.

yes. turning the screws Counter Clockwise is Richer, and turning them Clockwise is Leaner. gently screw the needles all the way in ( clockwise ) and then count the turn out to the starting settings. then start, warm up, and then start doing some tuing runs.

remember these arnt nitro motors. so very small needle movement are REQUIRED.

turning the needles on a gasser too lean even for a bit of time, will cause damage. unlike a nitor where you can lean the motor out until it wont run. do that on a gasser and it wont run, like you now know, but unlike a nitro, you cant re richen the needles and get it to run again.

Take some time and research how to tune these gassers, its not ALOT different from nitros, but enough to warrent a good understanding.

these carbs are very sensative to needle movements.

you can find some info here on tuning, and theres a SHITLOAD of it over on the HBF. www.hpibajaforum.com , which is this sites Sister Site.

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