problems:80 Honda CM 400 T/Slow fuel flow/Ignition Mis-Fire

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problems:80 Honda CM 400 T/Slow fuel flow/Ignition Mis-Fire

problems:80 Honda CM 400 T/Slow fuel flow/Ignition Mis-Fire 
Shadetree Mech. said 2007-08-19 20:23 
 
I am new to this on line info stuff !
I have two problems with my 1980 Honda CM 400 T, and I
need a good advice and/or discussion group.
PROBLEM:
Short version:
*****1) Slow flow of fuel to the Carb. Bowls
(seems like a vapor lock). If I force feed by squeezing the
the tube from tank to Carb.,engine will run. I
replaced tubing with clear vinyl tubing so I could
watch what is happening with the gas flow (great tip
for trouble-shooting). Open bowl bleed screws, fuel
flows freely into Carb. Also let bike sit for 30
Mins., fuel will fill the bowls, but it is a slow
trickle into Carb.
NOTE: Accelerator pump diaphragm
OK , no cracks & it is soft and flexible, (amazing
for 43,000 miles).
*****2) Very bad mis-fire under fast
acceleration. Idles well and runs OK under slow
acceleration until RPM reaches 4,500, then total
break-down of ignition firing.(Mis-Fire does show
up with Timing light hooked up to either plug wire)
Hope it is not the C.D.I. unit (black box).
NOTE: Stator has been re-wound &
Coil has been bench checked.
----HOPE YOU CAN CONNECT ME WITH THE RIGHT TECH HELP.
-------------Thanks, Shadetree Mech. 
 
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