82desmo Posted August 12, 2018 Report Share Posted August 12, 2018 (edited) Hi all, Well after 50 kicks the TL250 came to life! Very happy as this was the first time since I have owned the bike. There is an issue that requires attention however. The bike was idling ok even went for a short run around the yard on three occasions. However maybe just 3 minutes after starting with the idling remaining smooth down low, when I twist the throttle, it hesitates and backfires. Eventually it will stop. Kind of had to keep "micro" twisting the throttle slightly to keep it running. Starting it up not long after exactly the same sequence took place. (Prior to starting the bike, I replaced the fuel which was old, emptied the carby bowl.) Could this still be a fuel / carby issue or could it be a failing coil or something? Thanks for your opinions. Mal Edited August 13, 2018 by 82desmo Spelling error! Quote Link to comment Share on other sites More sharing options...
feetupfun Posted August 12, 2018 Report Share Posted August 12, 2018 If it runs OK once you get "above" the flat spot, it's likely to be a problem with the pilot circuit 1 Quote Link to comment Share on other sites More sharing options...
section swept Posted August 12, 2018 Report Share Posted August 12, 2018 Just draining the carb float bowl will not cure the issue. You will need to remove the carb and thoroughly clean any deposits and fuel gelling with care so as not to open up any fixed dimension passageways and jets. Thin wire such as copper could be used to gently push through any passageways and jets. Better still an ultrasonic clean by a professional or garage. Take a old look at the fuel tap too this can also get partially restricted by crude etc. Make sure the feed pipe from tap to carb is clear as well. Once you are certain there is no fault with the fuel side of things and the settings are correct, investigate the ignition further. As the engine starts and runs but hesitated to rev up this could indicate a high tension coil fault, fine when cold but as heat is generated an internal break in the coil winding may be opening up. There’s loads more to check and diagnosing from a distance is not ideal, but I would definitely go for the fuel side of things first. Good luck?? 1 1 Quote Link to comment Share on other sites More sharing options...
Tillerman6 Posted August 13, 2018 Report Share Posted August 13, 2018 Don't know if you are using ethanot in your fuel, but you might not know that ethanol eats rubber fuel lines from the inside out and deposits tiny bits of rubber into the carb where it clogs up everything. Some gas stations sell non- ethanol premium fuel and that is what I make all my 2 stroke mix out of. Also good to replace all rubber fuel lines with Tygon lines instead. also run a fuel filter just before the carb just for insurance. However, all that being said, a carb has more tiny holes in it than a piece of swiss cheeze. and they all have to be clean for it to work. 1 Quote Link to comment Share on other sites More sharing options...
82desmo Posted August 13, 2018 Author Report Share Posted August 13, 2018 Thanks guys, I will pull the carby first and break it down, soak, clean and replace. I have a fine filter in line and do not use ethanol added fuel - however I don't know what the previous owner used. I appreciate your comments. Quote Link to comment Share on other sites More sharing options...
maxwell smart Posted August 13, 2018 Report Share Posted August 13, 2018 (edited) Hello Mal, one thing u should check, on my bike when I first got it running it would start and idle well but seemed to have a major carb problem when given throttle around the house, the seat was actually blocking the airbox opening and only letting enough air to idle but not run right at speed. remove the seat and try with the airbox opening clear of the seat and ride it to see if that changes anything. I took my carb apart three times before I found the airbox opening too close to the seat bottom. one more thing, check the gascap for proper venting, either blow thru the line or remove the cap gasket and do a visual on the vent orifice to see if it is closing off from oxidation. Edited August 13, 2018 by maxwell smart additional info 1 Quote Link to comment Share on other sites More sharing options...
82desmo Posted August 13, 2018 Author Report Share Posted August 13, 2018 Hmmm, interesting Maxwell. Will have a look. Quote Link to comment Share on other sites More sharing options...
shakennstirred Posted August 15, 2018 Report Share Posted August 15, 2018 get a sonic cleaner and strip the carb down and give it 15-20 mins in the cleaner. 1 Quote Link to comment Share on other sites More sharing options...
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