trouble starting when hot

bikeman · 07-25-2019, 11:30 AM

Hawk 250 is running great. I have stock everything, including carb, but with two needle shims and a 110 main jet. I kick start it cold at half choke, and runs fine with no choke.

If I stall the bike when HOT or shut it down, I have not been able to get it restarted by kicking until the bike has almost completely cooled down. This takes 30 mins to an hour. My battery is currently dead/wont charge so kick starting is the only option. Realize that it takes only one kick to start from cool.

I have considered throttle positions, and have tried no throttle, full throttle, half throttle, just cracked throttle but nothing works. I have considered vaporlock, and have ensured no pressure differential from tank to carb by removing gas cap. I shortened the fuel hose from tank to carb to make a straighter path for fuel. Nothing works. I do notice that the tank outlet is almost level with the inlet on the carb. But still a downward path from fuel. Gravity should be at work here.

Could the A/F mix be off? I am currently running 1.25 turns out from seated at 0ft elevation. Again, the bike starts EASILY cold,cool, or warm. There is no rich exhaust odor or NOx lean odor from the tailpipe.

Upon manipulation of the throttle, I will achieve a "popping" noise on an attempted kickstart. I know the spark plug is firing, thats been tested. It must be a fuel/air delivery problem.

Anyone have experience with this, besides generic 4 stroke motorcycle advice? I know how to kickstart a bike. (Just maybe not THIS bike) I have had dirtbikes before but none have been as difficult as this one to start hot. Advice, questions, concerns, Bueller?

Thanks in advance.

07-25-2019, 11:30 AM	#1
bikeman Join Date: Apr 2019 Posts: 26	trouble starting when hot Hawk 250 is running great. I have stock everything, including carb, but with two needle shims and a 110 main jet. I kick start it cold at half choke, and runs fine with no choke. If I stall the bike when HOT or shut it down, I have not been able to get it restarted by kicking until the bike has almost completely cooled down. This takes 30 mins to an hour. My battery is currently dead/wont charge so kick starting is the only option. Realize that it takes only one kick to start from cool. I have considered throttle positions, and have tried no throttle, full throttle, half throttle, just cracked throttle but nothing works. I have considered vaporlock, and have ensured no pressure differential from tank to carb by removing gas cap. I shortened the fuel hose from tank to carb to make a straighter path for fuel. Nothing works. I do notice that the tank outlet is almost level with the inlet on the carb. But still a downward path from fuel. Gravity should be at work here. Could the A/F mix be off? I am currently running 1.25 turns out from seated at 0ft elevation. Again, the bike starts EASILY cold,cool, or warm. There is no rich exhaust odor or NOx lean odor from the tailpipe. Upon manipulation of the throttle, I will achieve a "popping" noise on an attempted kickstart. I know the spark plug is firing, thats been tested. It must be a fuel/air delivery problem. Anyone have experience with this, besides generic 4 stroke motorcycle advice? I know how to kickstart a bike. (Just maybe not THIS bike) I have had dirtbikes before but none have been as difficult as this one to start hot. Advice, questions, concerns, Bueller? Thanks in advance.
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