Topic: Carb help-'81 650c CV carbs

[cgswss]

Ok this bike was not run for many years.  Got her running on starting stray- turned on gas,  took a few min but cleaned up and ran very well.  Idle was way to fast so i tried to bring it down, bike drops to 2 cylinders.  Figure I have carb problems (was going to clean carbs anyway- just couldn't resist taking her for a blast up the street.

OK carbs off 1 and 4 look terrible, but I get them cleaned up good. 2&3 look great- but polit jets and idle jets are clogged solid.  Spraying carb cleaner down the ports no results, socked in acetone no good, soaked in lacor thinner no good trying to use tip cleaners (for welding torch)

What I'm wondering about is the feel.  Right now I go thru the jet and maybe 1/4 or less I hit a solid "wall".  I'm guessing the port makes a turn or something.  Now If I get the Guitar string,do these passages turn?  I'm unclear how you use the string to unclog the passage (jets are now clear)

Another odd thing.  Is there some other way of marking jets?  when I took off the bowls the jets were #1 70, #2 75, #3 70 #4 70.  First that seems way too low-I was expecting to see something around 100 and the stagger of sizes seem weird.  I changed them to put the 70s on the outside and the 75s in 2&3.  The bike felt good the little I rode it- little week to about 3500 then pulls like a race bike past 9000 ( I shifted at 9K, but the bike was still pulling great)

THe bike is stock- original exhaust and original air box.  And seemed to run great except for the low RPM issue.  Has anyone seen a 650 running that lean of jetting, or is there some other scale of jet sizes I don't know about?

Thanks!

Craig

[fmctm1sw]

There's a couple of good CV carb threads here.  I think F16viper had one.  Compressed air is what I used along with a individual strand from a wire brush.  One thing I always recommend is note how far the wire travels down the jet before it stops.  If the jets are clear, the wire should travel the same distance.  If not...

[cgswss]

SO you put in the wire, you feel the jet, you get the wire in hole in the jet, it goes about 1/4 inch further and thats it?  I'm sure the jet its self is clear.  I just wanted to know if it ends there because I'm that far a day ago and they still don't flow anything.  I wanted to know if there was an air passage behind the jet-if I should keep trying to go down- it feels like I'm down against the body of the carb.

[cgswss]

OH WELL.  I gave up.  the carbs are soaking now.  Even if they don't work, they will be shiny clean and smell piney fresh.

I also visited the Honda Dr. (Phil) in Waterford today and picked up some little parts including the "right" fuel line (at $3 per foot)  He told me that if I brought in the stripped down rack it would be $50 to $100 for him to get them done for me.  We'll see in a couple days... Been looking on-line at ultrasonic parts washers.  one big enough (12X6X6) is about $250.  wait... That means I could buy a NEW TOOL!

[fmctm1sw]

I just wanted to know if it ends there because I'm that far a day ago and they still don't flow anything.  I wanted to know if there was an air passage behind the jet-if I should keep trying to go down- it feels like I'm down against the body of the carb.

I believe the passage takes a 90 degree turn soon after the jet.  Other than compressed air, I don't know how you would get at that area.  My memory is coming back on this.  I pulled the air (fuel?) screw out, put a tube on it and blew air through it.  If you put a finger over the idle jet, you should hear a difference in the tone of the hissing when you cover and uncover it.  Did that make sense?  I should have taken a photo...

[fmctm1sw]

I should have taken a photo...

Looks like I did. Slip a piece of tubing over the idle mixture screw port (far right).  Blow (with your mouth) air into the tube and listen for the hissing sound of air flow through the idle circuit.  If you cover and uncover the idle jet (near the middle) while you are blowing into the tube, there should be a faint but distinct change in the sound.  You have to listen closely.  No change in sound means no air flow through it.  That's how I found mine.  Then it's a matter of unclogging the jet...

[cgswss]

Thanks- that make a LOT of sense to me! 

Now on to the next adventure

[cgswss]

Well after 3 days of soaking and multiple attacks with the air compressor, blaster, carb cleaner,  and guitar string, I still have clogged jets.  Damn I hate this!

[Tugboat]

Buddy of mine here in Nashville is having this exact same problem. He's cleaned his carbs - dip, ultrasonic, poked, compressed air.... - but his idle jets still seem to be clogged. Bummer. The bike will start and idle but you can't give it any throttle or it just dies. Hope you figure it out!!

[cgswss]

Found a new tool in the carb clean fight.  Disposable syringes with needles.  The needle goes inside the jet and you can get a good bit of force to break up the gook.  Worked for me!