pacificnw1 Posted May 2, 2016 Report Share Posted May 2, 2016 I'm out of ideas... Recently restored TY 250 runs and rides great until I run it fast - 3/4 throttle for a minute or two. Then it acts like it's out of fuel and shuts off. A minute later the thing fires and idles like nothing happened! So - new fuel delivery system complete - everything. Clark fuel tank and petcock, fuel lines, Micunni Carb, Boysen reeds and spacer - SAME thing! So - electrical. In resto I cleaned the mag case and replaced the harness from the Ignition side to the new coil, wire, cap and plug. I'm a competent solderer and again, it works great unlil it gets hot. I run 45:1 and have the oil pump blocked and line ports plugged. I have two guesses - crank seals, condenser. I don't really think they fit. Shorted stator windings at temp maybe? I was careful but I was in there. Ideas welcome - why's and follow ups welcome - I'm stuck and the machine is great - except it occasionally shut off. Didn't Volvo's used to do that? Ha! Quote Link to comment Share on other sites More sharing options...
spen Posted May 2, 2016 Report Share Posted May 2, 2016 I'd strip the carb' again and make sure there isn't a tiny bit of debris/rubber/rust/paint getting in to the main jet and then dropping back out when the fuel starts washing it out. Quote Link to comment Share on other sites More sharing options...
tony27 Posted May 2, 2016 Report Share Posted May 2, 2016 Fuel cap isn't venting properly, try a run where you know it stops either without the cap or it not fully seated Stator coil problems normally take at least 15 minutes to get a spark back after they get hot Quote Link to comment Share on other sites More sharing options...
spen Posted May 2, 2016 Report Share Posted May 2, 2016 Fuel cap isn't venting properly, try a run where you know it stops either without the cap or it not fully seated Stator coil problems normally take at least 15 minutes to get a spark back after they get hot I initially thought that, but I re-read the post and saw he'd been using a Clark remote reservoir and petcock....... Quote Link to comment Share on other sites More sharing options...
b40rt Posted May 2, 2016 Report Share Posted May 2, 2016 classic condenser failing symptoms. 2 Quote Link to comment Share on other sites More sharing options...
tony283 Posted May 2, 2016 Report Share Posted May 2, 2016 What size main jet are you running ? Quote Link to comment Share on other sites More sharing options...
laird387 Posted May 3, 2016 Report Share Posted May 3, 2016 classic condenser failing symptoms. Totally agree with Ross - only way to check is with different condenser. Quote Link to comment Share on other sites More sharing options...
searay175 Posted May 6, 2016 Report Share Posted May 6, 2016 Totally agree with Ross - only way to check is with different condenser. I vote condensor also! I had the same symptoms on the one I had and new points and condensor= no more problems. Quote Link to comment Share on other sites More sharing options...
pacificnw1 Posted May 7, 2016 Author Report Share Posted May 7, 2016 "Experience is the great teacher" they say. The condenser was in stock here in town (!) and I soldered it in on Thursday and it wouldn't start. The point gap was the first thing I noticed/guessed but the adjusting screw was 44 years old and wouldn't budge. Back together with a new screw for the points, the condenser and a host of other needed improvements and maintenance tasks that should keep her going another 44 years. It started right up and I rode it for more than two hours without the sudden death nonsense. Thanks to the kindness of strangers I am once again a happy vintage trials rookie at risk. Trials Central is skookum. (b40rt, Laird387, Tony283 and Searay175 specifically) 3 Quote Link to comment Share on other sites More sharing options...
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