ds80, its got me fucked

[lb99]

a mate of mine brought me his ds80 coz it woudnt go, it was going fine until his boy fell off it, then no go, it will startbut dies after a few seconds, the spark is good, the carb is clean, the piston and rings are really new, and to cap it off after invesigating, we found one crank seal to be damaged, so replaced both, as well as the main bearings coz they were a bit rough and were cheap as,thinking we had it sussed, I have just put it all back togeather only to find it still has the same symptoms, it will start after a few kicks and only run for a few seconds then dies, can any 2 stroke experts help?

[cowpoos]

its not air getting in around the carb [perished rubber manifold/cracked]

[lb99]

its not air getting in around the carb [perished rubber manifold/cracked]

nah. been there it seems all sweet, it'll be something simple, I just cant see it.

kick, kick, ringadingdingdingdingbwrrrrrrrrrr dead.

[cowpoos]

when carb was clean...floats get bent...causeing fuel starving? it sounds lke fuel starving so sorts.. what happens if you leave choke on?? can you start it with choke off?

[Subike]

Have you cleaned the exhaust out?
I dont know much about these things, but could be a restricted exhaust

[lb99]

done that too, the exhaust is as open as, I even tried it without the muffler on the end, just in case.
it just got louder

[lb99]

when carb was clean...floats get bent...causeing fuel starving? it sounds lke fuel starving so sorts.. what happens if you leave choke on?? can you start it with choke off?

choke makes no difference to running, but it does start easier, I tried turning the fuel off and draining some fuel from the float bowl to lower the level, any diff it made was marginal at best

[cowpoos]

take the float bowl off and make sure the floats arn't out of adjustment..and just for the sake of it..if you have a compresser and air gun...just blow lots of air through al the major orifaces..

[lb99]

take the float bowl off and make sure the floats arn't out of adjustment..and just for the sake of it..if you have a compresser and air gun...just blow lots of air through al the major orifaces..

yeah, thats my plan for tomorrow, I have to go to work soon, I tried it with the air filter off and got a backfire thought the carb when it was running (briefly), so maybe timing, but the stator plate didnt appear to have moved, (only one set of screw marks), it was giong hard until the young fella fell off it and it hasn't run properly since.

[tri boy]

Quick elec test. Remove sparkplug cap.
Fire the bike up with the HT lead on the plug, then pull it back about 10mm.
Watch the spark, and see if it dies out while the engine dies.
This should eliminate ign fault/burnt ign coil/dodgey ign coil etc.
If spark is still strong as engine dies, the fault is probably fuel related.
Good Luck.(Plug Caps can be a frequent high resistance fault also. Should be below 5000 ohms generally).

[lb99]

I bruised my footsie from kicking it over now it hurts to walk

[Paul in NZ]

Has he got some dirt in the fuel tank vent? Try it with the filler cap cracked open a bit.

[lb99]

yeah baby

thar she blows

I went through everything again this morning, carb : strip clean and blow out, as well as set the float level, Ignition : strip clean and check components + new plug
and tried to start her up, same result.
I poked and prodded for a while, scratched my head, listened to some led zep and contemplated trial by fire.
then out of sheer desperation I decided to retorque the head and barrell studs.... IT WOULD HELP IF I TIGHTENED THE HEADSTUDS UP AT ALL , a few clicks on the torqe wench and ringadingdingding, she idles fine, and pulls the meanest wheelies ever

it just goes to illustrate the effects of extreme fatigue and working to a deadline

[tri boy]

Good to hear you cracked it.
Enjoy the wee beastie, and forget about your lapse of concentration. We all have those moments.