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idles but wont rev

D

dlegge09

Big Wheel
I am new to the concours forum, but have view many times and fout very helpful info.

Problem: 1986 concours (california model) starts and idles perfectly.  I just rebuilt the carbs, did valve overhead.  I paid
special attention to make sure all passages in the carb were clean and carb cleaner flowed through them.  Float levels set
right at bowl part line.  The bike starts easily and idles well but will bogg and nearly die when given 1/2 to full throttle
(sitting on side stand in neutral).  Revs will climb past 4k if throttle rolled on very slowly, but engine will not maintain RPM
past 4k and this seems to me like a fuel starvation issue or ignition timing not advancing.  I've checked the diaphragms but
cannot see any pinholes, but it sure feels like its a vacuum problem.  Fuel seems
to be flowing fine no kinks or restriction in lines.

Can anyone help? 

Could it be electrical/ignition?  I am getting frustrated, not sure what else
 
Maybe the slides are stuck and the main jet needle isn't being pulled up?
I was able to test each carb individually for proper slide operation using a shop vac to pull air though them when I cleaned mine.
 
Most likely a carb issue.

Make sure none of the carb boots are leaking.
At idle spray damp start or carb cleaner around the boots and see if the idle changes.

Was the valve timing ever tinkered with? If the Inlet is timed on the wrong mark (there are two IN marks) it will do this.

Check the stator pickup gap is correct.
Fresh gas with no water in it? drain the bowls into a glass jar and check for water. 

If all that is fine then remove the carbs and get Ricks Carb overhaul article from the Cogmos library (members only) in the Fall 2006? issue of the Concourier.
 
Thanks for the suggestions, I suspected the slides as well.  I took the carbs off and used the shop air to blow from the inlet
side (held air nozzle 6" away) and all slides lifted.

I drained tank and filled with fresh gas, but it have not checked if water collected, so I'll do that and check for carb boot
leaks today.  Again thanks for the support! 
 
Checked for leaks using carb cleaner and spraying around carb boots # 3 and #4 had a loose clamp...
Tightened down clamps. The engine now revs past 4k but still boggs from 4k-6K.  It will rev past 6K now and will hold RPM
above 6K but seems to be really rich...pipes and mufflers extremely hot....melted/deformed the right side saddle bag.
I only ran it for 30 seconds to a minute at 7.5K - 8K RPM and it blued the mufflers.
I used K&L carb rebuild kits and read they require 2.5 turns out, but this seems way to rich.  I'm going to turn them back in
1/2 a turn and see if throttle response improves any.
 
I think I got it licked.  I pulled the plugs and #3 and #4 were almost black (over rich) as I suspected.  Checked the
idle air screws and sure enough some how in all my messing with the carbs taking rack off and back on again the screws were almost 4 turns out.  Set them to 2-2.25 turns and all is well.
 
[quote author= link=topic=25388.msg91692#msg91692 date=1286657379]
I think I got it licked.  I pulled the plugs and #3 and #4 were almost black (over rich) as I suspected.  Checked the
idle air screws and sure enough some how in all my messing with the carbs taking rack off and back on again the screws were almost 4 turns out.  Set them to 2-2.25 turns and all is well.
[/quote]
Sweet! Well done for figuring it out  :D

Ps please take a look at your profile as your Alias is blank
 
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