Author Topic: Hanging Idle: little help pod issue? (Read 11072 times)

Doggie · « **Reply #25 on:** July 23, 2011, 01:05:15 PM »

I'm following along with this post Scott, because i'm having the same problem with my CB550F. Hope we can work this out.

Doug

Nortstudio · « **Reply #26 on:** July 23, 2011, 02:37:31 PM »

I'll let you know what happens Doug. I really am obsessed at this point, but the heat is killing me. Not sure if I'll make it back across to the garage tonight, or just hit it early.

Have the boots in hand, ready for getting the pods off there. But before that, I'll go through the carbs one more time, making sure to check the needles for debris. I know they're all on the same clip number, so hopefully the stock air box and cleaning again takes care of it.

Scott S · « **Reply #27 on:** July 23, 2011, 08:04:03 PM »

Seriously...check those rebuild kit jets against the stock jets. TwoTired bent over backwards to help me tune my CB500 and it wasn't until I saw the difference in the jets that I knew something was wrong.

A lean condition can cause the idle to hang. Take another look at the pic I posted...see how small and oddly spaced the emulsion holes are compared to stock? I would NEVER have gotten it figured out without the stock Keihin jets.

Nortstudio · « **Reply #28 on:** July 23, 2011, 08:12:15 PM »

I opened up the old carbs to see what that jet was like, and IIRC the new onenis nowhere near as different as your are. They seem very similar. I'm pulling the new carbs from the bike tomorrow, make sure each jet & needles are cleaned again etc.

I went back and checked my work with the valves and timing, and everything looked good. So I'm hoping your boots on this thing, with the stock air box, will set me straight.

dave500 · « **Reply #29 on:** July 23, 2011, 10:57:19 PM »

those wrong slow jets you have scott will be for a different carb but have the same thread,someone has fitted them anyway,they look like mikuni ones?

Scott S · « **Reply #30 on:** July 24, 2011, 03:54:51 AM »

One of those sets came in the carbs when I got the bike, the other came in a rebuild kit. I can't remember where I got the kit now, but it was from one of the shops listed in the FAQ section and they were advertised/sold as kits for my carbs.

The larger jet on the left came from a bank of carbs I pulled from the junkyard.

Doggie · « **Reply #31 on:** July 24, 2011, 07:13:58 AM »

I have both kinds of jets too. This week i'll tear into my carbs again and check to see if I have the large or small ones in them.
Good luck Scott. Stay cool. Doug

Nortstudio · « **Reply #32 on:** July 24, 2011, 07:38:05 AM »

I confirmed today that the jets are the same in old and new carbs. Both are the smaller size type in scott's photo.

One thing I noticed is that although the float needles look the same, the ones in the new carbs do not allow the float to push down as easy.

EXAPMPLE: When the carbs are upside down, the floats in my old carbs push down the float needle just by the weight of the float itself. The current one holds the float up more, barely allowing it to sink from the weight. Both are measured to 22mm when just at the touching point - float tang to needle.

I'm not sure which would be best???

Scott S · « **Reply #33 on:** July 24, 2011, 08:42:39 AM »

If you have the small jets, order the correct ones from Honda or Keihin. It was an immediate change on my bike when I installed the correct OEM jets.

Nortstudio · « **Reply #34 on:** July 24, 2011, 08:54:40 AM »

Are the large ones the correct ones?

Scott S · « **Reply #35 on:** July 24, 2011, 09:09:34 AM »

Quote from: Nortstudio on July 24, 2011, 08:54:40 AM

Are the large ones the correct ones?

Yes.
Often, a hanging idle is a sign of a lean condition. Those are the jets that the engine is "On" at idle and just above. Notice the "emulsion tube" on the three jets; the small pipe with holes in it. See the spacing and size of the large, stock jet? Compare that with the spacing and size of the holes in the aftermarket jets. No matter what I did, I couldn't get enough fuel through the aftermarket stuff. Any needle clip changes, main jet changes, etc., are for different parts of the operating range and won't affect the low end idle.

Nortstudio · « **Reply #36 on:** July 24, 2011, 10:18:44 AM »

The weirthing is that I had the exact same small ones in my old carbs, and i think I was always running rich. I'm now officially chasing my tail

Just got the carbs back on the bike (again) and will see if the cleaning and different float needles helped any....

Doggie · « **Reply #37 on:** July 24, 2011, 08:18:31 PM »

Good luck Scott. I dug out 4 sets of 069a carbs that were on my shelf. I'm going to tear them apart and build a new set with the large jets. See if it makes a difference. Let me know how yours turned out. Finally got my points and timing right after buying a new advancer, new backing plate and points. Now its carb time!!!
Doug

dave500 · « **Reply #38 on:** July 25, 2011, 02:21:12 AM »

i would imagine that using the short ones itll be like you have a very low float hieght as "seen" by the idle circuit?

Nortstudio · « **Reply #39 on:** July 25, 2011, 04:20:09 AM »

That makes sense Dave.

Can anyone suggest a source for jets that they trust will be the correct ones, since these incorrect ones are coming from supposedly trusted sources?

andy750 · « **Reply #40 on:** July 25, 2011, 04:50:51 AM »

Hey Scott good troubleshooting so far and I wish you luck in getting it sorted. I also agree about the stock jets v aftermarket and went through this recently myself on the 750. What fuel level gadget thing are you using and where did you get it?

Good luck in getting this sorted!
Andy

P.S. We need to plan a NY ride!

Nortstudio · « **Reply #41 on:** July 25, 2011, 05:13:24 AM »

Definitely need a ride once I get this thing straight!

The gadget is just a clear hose and perfect size coupler with o-ring to go in the float drain screw. Member Duanob turned me on to it. TAS Motorsports sells it, and its listed under:

"CB750, CB550, CB500, CB360 Float Level Tester Tool"

I would think its Simple enough to make if you can find the coupler.

Got the carbs back on the bike with the wrong jet - but cleaned and rechecked thoroughly, and then the door over at the garage was busted - so I couldn't test it! Going to try to see if I can get it up and running normal today before I head out of town until Friday. If it doesn't work correctly, it will eat at me every day until then

Bankerdanny · « **Reply #42 on:** July 25, 2011, 07:54:02 AM »

I didn't replace my jets when I did my carbs, they really don't wear out.

I soaked them in carb dip, then blew aerosol carb cleaner through them, then followed up with compressed air (keep a good grip on the jet so it doesn't blow across the room).

My carbs looked like they had dried caramel in them when I started, but when they were cleaned and reassembled I had no idle issues or lean or rich running.

Nortstudio · « **Reply #43 on:** July 25, 2011, 07:58:49 AM »

I did the same. Thorough cleaning, blow dry etc...

They are back in the carbs now, and I will see if I can make them work until I can source the proper jets. The ones in there now were in my old rack, and I never ran lean, always rich (which is what prompted this purchase & rebuild of the rack I have now).

Hoping I have the same luck as you Danny.

Nortstudio · « **Reply #44 on:** July 25, 2011, 08:41:51 AM »

The garage door is still busted, but I couldn't wait. So, I fired it up (hoping to avoid carbon monoxide poisoning), and it hung for a bit again, in the very beginning. I adjusted the down, and she fell into a comfortable rhythm.

Granted, I didn't have it going too long, but it started up fine on first hit, and continued a decent, non-hanging RPM through about 10 blips of the throttle.

I even found myself missing my old friend, LEAKING GAS

. Keep in mind, this was only a test for about 10 minutes, and none of it under load, but it will serve as a relief, since I am leaving the bike for 4 days.

When I return:

A) Check float level with gadget
B) vacuum sync
C) new plugs (again!)
D) clean the uni air filter
E) many, many, many other things...

Thanks for all te help folks. I'm sure it's not completely there, but closer than I was yesterday!

Nortstudio · « **Reply #45 on:** July 29, 2011, 01:12:28 PM »

Well folks, after a few days away from the bike, I came back to try it out with the stock air box and new boots installed. Seems I am still having a few issues (shocker!), but I want to approach this as methodically as possible.

I started up the bike today several times, and took it for one ride. Sometimes it seems to have equally hot headers, and other times #4 is colder. I checked the #4 carb float level (the one that gave me the most issues) with the clear tube. The level of gas in the tube was just about at the lip of the bowl. Checked #1 for comparison, and it's the same.

At one point, after shutting the bike off, the gas came out of #4 overflow. When I put the petclock on again to fill it (with clear tube to check), it did not fill. What would cause gas not to get to the bowl at all? #3 had gas in the bowl.

Next up will be the throttle cable adjustment. I am going to try to get it as perfect as I know how, but there seems to be some issues with that as well. Since these carbs were brand new to me, I have no frame of reference for them.....

MoMo · « **Reply #46 on:** July 29, 2011, 01:33:55 PM »

At one point, after shutting the bike off, the gas came out of #4 overflow. When I put the petclock on again to fill it (with clear tube to check), it did not fill. What would cause gas not to get to the bowl at all? #3 had gas in the bowl.

It can only be one problem if the other three carbs are getting gas-a stuck float needle. To get around pulling the carbs(if tapping the body does not free the needle) I have removed the carb drain plugs and blew low pressure air into the gas line. Keep at it , you'll get it rectified...Larry

Nortstudio · « **Reply #47 on:** July 29, 2011, 03:33:29 PM »

Thanks photolar (and everyone else who has held my hand through this carb journey!).

Right now, it's been idling for about 10 minutes. All headers are hot again (knocked #4 with a mallet). Every minute or so, I got a backfire out of the right muffler (4-2). But it hasn't done it in 5 minutes.

Then I shut it off and the gas came pouring out. Checked header again, and it was hot, but cooler than the rest. This leads me to believe that it was just running on the fuel in the float, and then ran out. Sound right?

So it seems you are right. Stuck float needle (killing me!!!). This has been going back and forth for a while. Seems maybe I should try a new needle??? Is it possible to have this happen multiple times and then work from your method of blowing it out?

I guess what's confusing me is that I have always had a stuck float needle come loose, and then stay loose. Not this back and forth behavior.

Thanks for your help.

MoMo · « **Reply #48 on:** July 29, 2011, 05:47:10 PM »

Was the bike sitting for a long time? Maybe the inner spring part of the needle is gummed up, consequently the float level would change. Also, the pin that goes throught the float could be gummed up or binding. In this heat I wouldn't let the bike idle for that long without a fan...Larry

TwoTired · « **Reply #49 on:** July 29, 2011, 05:48:09 PM »

Do the floats stick parked on the center stand or the side stand?

The float pivot pins can be polished.
The float hinge sides can be polished as well as the the carbs where they make contact at the carb body.
Verify the valves move freely in the valve seat housings.

Look closely at the cones of the float valve. Is the cone "worn"? Is it still matched with the seat it has worn in to fit?

Cheers,

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Author Topic: Hanging Idle: little help pod issue? (Read 11072 times)