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help! DT250 runs like crap


rasme360
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hey everyone, i just found this site! i have several early 70's enduros. i just finished a total restoration on a 72' dt 250. but i can't get the dang thing to run for crap. new top end, new clutch, new points, and set timing. rebuilt carb, good clean fuel source.........but it won't hardly get outta its own way. starts and idles nicely, but under a load it craps out, no power, and misses when gaining rpm's. any ideas? could the original exhaust pipe be plugged? could the timing be off even though it starts and idles nicely? after it warms up, it starts pinging real loud and seems to get hot pretty quickly.....anyway, i'm just frustrated, the bike is beautiful, but not much fun to ride. any help would be appreciated. thanks, rick

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hey everyone, i just found this site! i have several early 70's enduros. i just finished a total restoration on a 72' dt 250. but i can't get the dang thing to run for crap. new top end, new clutch, new points, and set timing. rebuilt carb, good clean fuel source.........but it won't hardly get outta its own way. starts and idles nicely, but under a load it craps out, no power, and misses when gaining rpm's. any ideas? could the original exhaust pipe be plugged? could the timing be off even though it starts and idles nicely? after it warms up, it starts pinging real loud and seems to get hot pretty quickly.....anyway, i'm just frustrated, the bike is beautiful, but not much fun to ride. any help would be appreciated. thanks, rick

what does the spark plug tell you?

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Hi i have a DT125 74 and having the same problems, have posted about it before under 'DT125E troubles' had some responses (thank you) and tryed them.

Still not working, same as above ticks over fine, kicks up first kick but runs like a bag of Sh**t when i open her up. boggs out and loses power.

I tryed loosening the exhaust and running with it not conected properly to see if it was blocked (you up there, hi, could try that to see if the exhaust is blocked, makes a hell of a noise tho :D ) but still ran the same.

Any ideas?

(rasme360) If i work anything out on mine will let you know tho buddy and if you do please let me know also.

Thanks

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i would say the spark plug is saying....."too lean you idiot" LOL

but does that mean timing, fuel, what? thanks, rick

check fuel flow from tank, crap in bottom or vent blocked

check timing first cause that's the easy part. try raising the main needle up 1 notch to see if that helps. ( 2nd easiest)

check float levels and use a jet kit and replace the jets and clean out carbs using an ultrasonic bath if you can borrow one.

fit an inline fuel filter now before more sh!t gets in there.

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well, fuel flow from tank is good, and i have a new in-line fuel filter already in place.

you said timing is easy to check, can you talk me through this procedure??? i completely re-built this bike, but took it to the local corner shop to have the points put in and timed. (someone told me it was complicated)

someone else told me that if the crankshaft seals were bad, it would run very poorly also. i never got into the bottom end of this engine. could this be a possibility?

i have played with each and every setting on the carb rod. seemed to make very little difference. thanks everyone for responses.......rick

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well, fuel flow from tank is good, and i have a new in-line fuel filter already in place.

you said timing is easy to check, can you talk me through this procedure??? i completely re-built this bike, but took it to the local corner shop to have the points put in and timed. (someone told me it was complicated)

someone else told me that if the crankshaft seals were bad, it would run very poorly also. i never got into the bottom end of this engine. could this be a possibility?

i have played with each and every setting on the carb rod. seemed to make very little difference. thanks everyone for responses.......rick

I'd PM mervin, the last 2 stroke I did was 15 years ago. if the laberynth seals are gone you would get white smoke from the exhaust and your gear box oil level dropping.

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i pulled the spark plug again last night.....it actually looks more "oil fouled" than anything. this is a brand new plug, and maybe a mile of riding(it runs so poorly that i don't even ride it)

but the plug is entirely black, no clean burn areas, and carboned slightly everywhere.....

i did check the fuel flow from tank again, trust me, there is NO PROBLEM there. i flowed fuel all over my hot drop light under the bike. LOL (i thought i had the fuel shut off, but was in reserve position instead) surprised i didn't burn my garage down!!

anyway, does anyone know how to check the timing on these bikes? i was told you have to pull the head, and use a dial indicator or something like that.........

thanks again, rick

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i pulled the spark plug again last night.....it actually looks more "oil fouled" than anything. this is a brand new plug, and maybe a mile of riding(it runs so poorly that i don't even ride it)

but the plug is entirely black, no clean burn areas, and carboned slightly everywhere.....

i did check the fuel flow from tank again, trust me, there is NO PROBLEM there. i flowed fuel all over my hot drop light under the bike. LOL (i thought i had the fuel shut off, but was in reserve position instead) surprised i didn't burn my garage down!!

anyway, does anyone know how to check the timing on these bikes? i was told you have to pull the head, and use a dial indicator or something like that.........

thanks again, rick

Does this have a separate 2-stroke tank or is it pre-mix? Maybe you're getting a little too much 2-stroke oil through. Are you giving the engine long enough to warm up? (I.e. is this a problem with the choke?)

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this bike still has the oil injection system in play....works fine, so no pre-mix. i adjusted the oil injection per clymers. the bike does smoke quite a bit, so i guess it could be getting too much oil.

yes, i let the bike warm up, and then take choke off. doesn't seem to matter, still runs like crap.

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