dsb2014 Posted February 28, 2014 Share Posted February 28, 2014 hi again every 1 im having another problem with my dtr i got it sparking there's good compression but all its doing is back firing does any 1 know any reasons this may be happening and not starting ??? Link to comment Share on other sites More sharing options...
slice Posted February 28, 2014 Share Posted February 28, 2014 To much fuel not enough air would be my first guess, adjust the air flow and fuel flow. Link to comment Share on other sites More sharing options...
Moderator DirtyDT Posted February 28, 2014 Moderator Share Posted February 28, 2014 Clean the carb and reset it. Clean the plug and reset the gap. Check the timing. Leave the plug out for a few hours. Pour a spoon full of 2 stroke oil down the spark plug hole. kick over a couple of times. Pour a spoon of fuel down the spark plug hole, repalce the plug and HT lead and kick the bike over with no throttle. Link to comment Share on other sites More sharing options...
Moderator Airhead Posted February 28, 2014 Moderator Share Posted February 28, 2014 Try a new plug Link to comment Share on other sites More sharing options...
dsb2014 Posted March 1, 2014 Author Share Posted March 1, 2014 thanks guy i will try today. ive got a new plug for it and its still the same.cheers i will update later on Link to comment Share on other sites More sharing options...
dsb2014 Posted March 9, 2014 Author Share Posted March 9, 2014 well a quick update had to get a new air fuel screw got it fitted OK so iv reset it the carbs been cleaned a new plug and nothing just a good back fire the bike was running fine wen i got it all ive done is put a servo on full dep system new air filter piston and rings and full bottom end rebuild check the plug after a few back fires theirs fuel and oil on it so theirs fuel going through there's good compression and spark so im stumped. check the timing i through dt125r were set and couldn't be changed, im desperate now more than ever as im going to Spain in two weeks for a biking holiday and i need her lol Link to comment Share on other sites More sharing options...
dt502001 Posted March 9, 2014 Share Posted March 9, 2014 Pull the nut off the flywheel and check the key hasent spun. Link to comment Share on other sites More sharing options...
dsb2014 Posted March 9, 2014 Author Share Posted March 9, 2014 Pull the nut off the flywheel and check the key hasent spun. how do u mean spun pal ??? Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 9, 2014 Moderator Share Posted March 9, 2014 the mag can shear the woodruff and spin on the crank. causing the timing to change Link to comment Share on other sites More sharing options...
dsb2014 Posted March 10, 2014 Author Share Posted March 10, 2014 the mag can shear the woodruff and spin on the crank. causing the timing to change are right i get it now lol. So basically the the fly wheel is not tight on the crank hence it not spinning where it should be cheers fellas i will check today Link to comment Share on other sites More sharing options...
dsb2014 Posted March 11, 2014 Author Share Posted March 11, 2014 well today i have had the fly wheel off and took the woodruff key off looks ok. So i took it to my local garage and they said it looks fine. I have put all back together and tried again no joy ive double checked all the rubbers around the carb are fitted tight but still no joy the plugs wet so fuels getting through Link to comment Share on other sites More sharing options...
Moderator drewpy Posted March 11, 2014 Moderator Share Posted March 11, 2014 can you reset the timing or is it a fixed electronic type? Link to comment Share on other sites More sharing options...
Moderator Cynic Posted March 11, 2014 Moderator Share Posted March 11, 2014 Have you removed or loosened the stator plate, (the bit with the coils on in the mag). If so did you put it back EXACTLY where it was to begin with? If that plate has been put back out of position by more than 3 or 4 mm she will just backfire. Link to comment Share on other sites More sharing options...
dsb2014 Posted March 13, 2014 Author Share Posted March 13, 2014 ive had the stator off twice and just put it back where the holes lined up for the bolts i think the timings set with the eletronics and wen ive rebuilt it the balancer cog and the other 1 both have woodruff keys on so they can only be lined up 1 way arrrgggghhhhhhhh Link to comment Share on other sites More sharing options...
Moderator Airhead Posted March 13, 2014 Moderator Share Posted March 13, 2014 Have you got a haynes manual? Have you got a multimeter? Have you tested all the resistances of the coils both the HT coil and the stator coils, as per the spec in the manual? If the answer is yes yes yes then maybe the cdi is u/s Link to comment Share on other sites More sharing options...
dsb2014 Posted March 14, 2014 Author Share Posted March 14, 2014 the bike was running before i had the full rebuild. it was running sweet. could the piston be a fault and causing back fire ???? Sent from my GT-S5360 using Tapatalk 2 Link to comment Share on other sites More sharing options...
dsb2014 Posted March 14, 2014 Author Share Posted March 14, 2014 had a idea that the reeds may b in the wrong way but does any 1 know if they can be ??? Sent from my GT-S5360 using Tapatalk 2 Link to comment Share on other sites More sharing options...
Moderator Airhead Posted March 14, 2014 Moderator Share Posted March 14, 2014 is there an arrow on the piston crown? if there is it should point to the front of the bike Link to comment Share on other sites More sharing options...
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