Carb Air Cut Valve issues
#1
01-29-2018, 09:38 PM
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Carb Air Cut Valve issues
I built a Mid Engined Trike based on a Donor 98 F3 engine that I found never starts in cold weather, but runs great when hot.
I have to use Starter Fluid to get it started along with draping a cloth over the air intake to keep it going until it warms up.
Choke which appears to but working from the outside...has little effect
Pulled the carbs to rebuild and noticed the outside Air Cut Valve hose was broken off the valve.
My research shows that the Air Cut Valves purpose is to eliminate backfiring on deceleration I found no information on it having any part of the start cycle.
My question is...can this broken hose cause hard start when cold?
I ordered a new Air Cut Valve but won't be here for a few days.
Then Carbs go back together.
Any ideas???
Thanks in advance
I have to use Starter Fluid to get it started along with draping a cloth over the air intake to keep it going until it warms up.
Choke which appears to but working from the outside...has little effect
Pulled the carbs to rebuild and noticed the outside Air Cut Valve hose was broken off the valve.
My research shows that the Air Cut Valves purpose is to eliminate backfiring on deceleration I found no information on it having any part of the start cycle.
My question is...can this broken hose cause hard start when cold?
I ordered a new Air Cut Valve but won't be here for a few days.
Then Carbs go back together.
Any ideas???
Thanks in advance
#2
01-30-2018, 01:49 AM
#3
01-31-2018, 11:32 AM
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but returning to the larger question, would the broken rubber hose that is connected to the air cut valve being open to the air and not connected cause the starting issue?
#4
01-31-2018, 11:37 AM
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#5
02-01-2018, 01:01 AM
The air induction system is half there, everything that screws down to the top of the carburetors is there but the two small rubber elbows and the top section that normally sits in the front of the motorcycle is not there due to space restrictions. But I have always wondered if that might be the issue that it is running too lean because of the larger amount of air that’s being induced. Thinking that is why I have to put a cloth over the two circular intake ports on the air box to reduce the amount of air. That seems to keep it going until warms up.
but returning to the larger question, would the broken rubber hose that is connected to the air cut valve being open to the air and not connected cause the starting issue?
https://thumpertalk.com/forums/topic...toff-valve-do/
As regards the DAI here's a mod that gets rid of the air solenoid
And
http://www.motorcycleproject.com/tex...alve_more.html
Could be the air isn't pressurising the float bowls with the solenoid in the way
Last edited by CaBaRet; 02-01-2018 at 03:22 AM.
#6
02-06-2018, 06:56 PM
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