SMOKES after cleaning

Correctly servicing the Carburettors on these bikes is paramount to good running and fuel economy so any work done will pay back in better mileage :)
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SMOKES after cleaning

Postby <742d.html?mode=viewprofile&u=706">saltwatersurf » Fri Jun 18, 2010 1:06 pm

So I delayed a trip for a day, stayed up till 3 in the morning and got the carbs good and clean with drill bits, CLR, carb cleaner etc. It eliminated the extreme stutter and cutting out it had. Now it runs really well except for two things. The idle can't seem to stay constant. It idles at 2 or 3 thousand or it just wants to idle at nothing and you have to keep it going with the throttle. Oh and it runs really rich, smokes and the plugs are black. Any quick tips before I take it on the trip?

Air fuel screw is out 1 5/8 turns. Messed with the idle screw a bunch. Checked throttle cables for binding. Choke is operating correctly.

THANKS
riding: 78 CX500 21,000 miles,
restoring: 79 CX500, 80 CX500 Custom
Rolling the pavement without a payment.
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Re: SMOKES after cleaning

Postby Gman » Fri Jun 18, 2010 1:26 pm

High idle usually means an air-leak around the card boots.
Spray Carb cleaner/WD or Hairspray around the boots whilst trying to hold the bike at idle.If the engine speed changes in either direction there's the problem.
If in-line fuel filter fitted re-check flow direction.
Re-check Primary and Secondary main jets have not been reversed.78 into carb body.112/115 into Brass emulsion tube.Be sure black small bungs are on the middle tube hole between the two jets.
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Re: SMOKES after cleaning

Postby <742d.html?mode=viewprofile&u=706">saltwatersurf » Tue Jun 22, 2010 1:02 am

Re-check Primary and Secondary main jets have not been reversed.78 into carb body.112/115 into Brass emulsion tube.Be sure black small bungs are on the middle tube hole between the two jets.

I'll double check this tonight.
I did spray around the carb boots and couldn't tell if it was racing because of the spray or just doing what it normally does which is the problem. It seems to sporadically change idle speed for no reason. Sometimes it idles at 4K, sometimes at 2K, and sometimes it won't idle unless you blip the gas. It will even change at mid idle.
riding: 78 CX500 21,000 miles,
restoring: 79 CX500, 80 CX500 Custom
Rolling the pavement without a payment.
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Re: SMOKES after cleaning

Postby Gman » Tue Jun 22, 2010 11:29 am

That still points to either an air-leak or incorrect float heights but also see this thread,
http://choppercharles.com/cs/forums/202 ... spx#202991
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Re: SMOKES after cleaning

Postby <742d.html?mode=viewprofile&u=706">saltwatersurf » Tue Jun 22, 2010 10:50 pm

Whew. Finally I got it. I swapped some idle jets (#45) from another CX and it ran perfectly. Apparantly I used too big of a drill bit when cleaning the jet. The local shops can only get the 112 or 78 jets. Is there anywhere in the States this part can be ordered?
riding: 78 CX500 21,000 miles,
restoring: 79 CX500, 80 CX500 Custom
Rolling the pavement without a payment.
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Re: SMOKES after cleaning

Postby Gman » Wed Jun 23, 2010 1:24 am

I know there have been recent threads supporting Larry's method of cleaning however he is meticulous and careful.I NEVER use metal into any jets.In 30 years of servicing carbs I've never found a need to.I use several methods all none harmful

1:A thick nylon brush bristle will do and not harm to the soft brass jets.
2:Boiling the brass parts/jets and emulsion tubes out of the carbs in a pan with some washing soda crystals or washing up liquid and let simmer for half-an-hour.
3:Ultrasonic cleaner if you can afford one.

All blown through afterwards with my compressor.


Note:This is NOT the same as using say a needle or guitar string through the emulsion tubes side holes as these are not jets and so long as you are careful their diameter is not critical if done with care.
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Re: SMOKES after cleaning

Postby Gman » Thu Jul 08, 2010 1:32 pm

There should be no extra lubrication used in the slides of the Constant velocity carburettors used on these bikes.
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Re: SMOKES after cleaning

Postby Randall-in-Mpls » Mon Aug 02, 2010 4:19 am

Did the vacuum pistons get swapped, maybe? If the pistons and covers don't stay matched, they might stick a little.

R
1978 CX500 - Black Grub
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Re: SMOKES after cleaning

Postby Gman » Mon Aug 02, 2010 10:31 am

Randall-in-Mpls wrote:Did the vacuum pistons get swapped, maybe? If the pistons and covers don't stay matched, they might stick a little.

R



Good point.I clean/polish my slides/pistons with some metal polish and then clean off.Not to a mirror finish but enough so they are smooth and clean and then check they slide up and down easily. without catching.
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