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Hard start when hot


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Posted

Need some help here folks. Finally finished the build and fired it up. Cold start isn't great but I've got it down to having to twist the throttle 3 or 4 times(has flatslides), pull the choke and usually it will start after a couple of goes. Idle mixture is slightly on the rich side. Once it's warmed up. it's an absolute ball tearer, no flatspots and idles well. 

Problem is. once I shut it down. it's very difficult to restart. I've tried the idle mixture from slightly rich to lean which doesn't seem to help. I've tried starting with no throttle to slowly opening the throttle, pumping the throttle, slamming shut the throttle but nothing seems to work. I've checked the tank breather which is fine. Spark plugs look slightly rich but not enough to be an issue. 

Engine has a weaker than normal crank speed due to the high comp and kicks back a bit when it doesn't fire. Also has a 4 degree advancer

My other 7/11 had a very weak crank and would struggle to start but since converting to 24v start . it's been perfect since. Difference is, it wouldn't start cold or hot which leads me to believe it's a different issue with the new bike

Any ideas appreciated

Posted

Engine only has 70k;s on it since rebuild. To me it feels like a carb issue or a voltage drop issue but would be good to hear of similar experiences and opinions. Was thinking of removing the ignition advancer

Posted
On 8/8/2018 at 10:08 AM, george 1100 said:

Engine has a weaker than normal crank speed due to the high comp and kicks back a bit when it doesn't fire. Also has a 4 degree advancer

Well - a fixed advancer isn't a good idea for starting a High Comp motor. You could try switching the ign. independently of the cranking so that engine will crank with ign off and once its spinning light the sparks. Or as before use 24v starting!

  • Like 1
Posted

Yes,  might swap out the advancer as the first step then convert to 24v start and see how that goes. 24v mod certainly resolved the severe kickback  and starting issues on my other beastie. Only difference between the two is that the latest build is only hard to start when hot where as the other was an issue whether hot or cold

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