Posted February 18, 200916 yr right guys i have a dt (r?) 125, its water cooled and ive spent close or more than £400 on it getting it running, new pistons, carbs, rings, gaskets etc! It was running mint today, i left it in the garden ticking over and used a full tank of fuel, so thats the rings run it tidy, so today i went out and it was running fine, then towards the end of the day it just went buuurrrghhh and said f-ck off im not going no more! When bumping or trying to kick it over, its popping and backfiring, and im getting fireballs, i suspected headgasket, but no symptons or any sign of water in the wrong places, cleaned carb out as there was not alot of fuel going through but still the same problems, getting a lovley spark! What next?" im close to giving up im at my wits end with it! problems problems problems! thanks alot in advance!
February 18, 200916 yr Author take the head and barrel off and inspect the rings there brand new rings, it ticked over on half a tank of petrol plus a bit more, it was left about a day, failing that how long do you need to run it to run the rings in? is it 500 miles? so just stick the back end up, 1st gear and let it spin all day? nightmare!
February 18, 200916 yr there brand new rings, it ticked over on half a tank of petrol plus a bit more, it was left about a day, failing that how long do you need to run it to run the rings in? is it 500 miles? so just stick the back end up, 1st gear and let it spin all day? nightmare! 500 miles is usually correct, but you must ride it, the engine must be under load, ie riding it and keeping the revs low. Im guessing you have opened it up and the rings have nipped up on the exhaust port side, I would definately want to inspect the bore and rings if it was mine
February 18, 200916 yr Author 500 miles is usually correct, but you must ride it, the engine must be under load, ie riding it and keeping the revs low. Im guessing you have opened it up and the rings have nipped up on the exhaust port side, I would definately want to inspect the bore and rings if it was mine no more bores left eek! so i will inspect the rings tomorrow which will most likely be the cause, ill have to get some more and take my time, 500 miles is along time, how normally would rings be run in for any body else? as where i go is the mountain so that would probaly take me months to run in, going out twice a week for about 4 hours a time. so dont be hitting the power band when sitting the rings in!
February 18, 200916 yr no more bores left eek! so i will inspect the rings tomorrow which will most likely be the cause, ill have to get some more and take my time, 500 miles is along time, how normally would rings be run in for any body else? as where i go is the mountain so that would probaly take me months to run in, going out twice a week for about 4 hours a time. so dont be hitting the power band when sitting the rings in! exactly, I done the exact same thing on my dtx when i had a top end rebuild, lucky enough the piston and rings werent damged but the rings had been jammed at the exhaust port side, we were able to pluck them back out and continue running it in. its very hard not to hit the powerband but you must do it to bed the rings in correclty, otherwise your asking for trouble. take a few photos when you strip the top end so we can see what has actually happened
February 18, 200916 yr Author exactly, I done the exact same thing on my dtx when i had a top end rebuild, lucky enough the piston and rings werent damged but the rings had been jammed at the exhaust port side, we were able to pluck them back out and continue running it in. its very hard not to hit the powerband but you must do it to bed the rings in correclty, otherwise your asking for trouble. take a few photos when you strip the top end so we can see what has actually happened will do, have you a link or file for a workshop manual for one of these bikes, i had one off here before but that was 2007 and i cant find posts that date that far!
February 19, 200916 yr no more bores left eek! so i will inspect the rings tomorrow which will most likely be the cause, ill have to get some more and take my time, 500 miles is along time, how normally would rings be run in for any body else? as where i go is the mountain so that would probaly take me months to run in, going out twice a week for about 4 hours a time. so dont be hitting the power band when sitting the rings in! Hi There, I went to Yamaha's factory in 1980 and every bike I saw come off the production lines was red lined in each gear at the end of the line then ridden down to the packing dept with great haste .. when I was there I saw RD250LC's given a bending on one line as Passolas given a thorough work out on another !! Are you sure the spark is being delivered at the correct time ? The fault you mention can be just the ignition timming out... I guess the bike is a DT125LC of some form and if the CDI box or pulse coil has gone U/S the ignition timming could be well out .. hence a dry plug & misfires but I guess you need to strip the engine to see if you still have compression Regards Jim
February 19, 200916 yr will do, have you a link or file for a workshop manual for one of these bikes, i had one off here before but that was 2007 and i cant find posts that date that far! http://www.dtr125.net/workshop-manualf.htm try that, although you shouldn't really need it to remove the top end, its quite simple, let me know how you get on
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