Author Topic: CB500 rich condition update: now w/ Pics (Read 10252 times)

brett_bike · « **Reply #25 on:** August 20, 2009, 08:57:31 PM »

Spanner1 - I'm Riding to Boulder From Denver and back tomorrow. I'll Check the plugs when I get to my buddies house in Boulder.

Bender01 - I forgot to mention that they have been "bench sync'ed" to the "look for light" method. When I did the carb sync, the idle adjust screw was about 7/8th of the way out.

After my ride tomorrow I'll inspect the plugs and post my findings. Thanks for all the help fellas.

brett_bike · « **Reply #26 on:** August 24, 2009, 06:25:45 PM »

Did my ride to Boulder, did a plug chop and here's what I saw.

I still have the stumbling from idle to 1/4 throttle. Also I noticed when I'm cruising (just holding my speed), I can feel the slightest hesitation. Pretty much the same sort of stumbling, just to a lesser extent. I've tried removing the Uni filter, pretty much the same. The air screws are now at 2 full turns out, if they are screwed in any further, the bike stalls when I come to a stop. It appears to me that I'm still a little rich, even though the plugs are not equal in deposits. That leads me to believe that I should probably go with a smaller slow jet (currently a #40). Any thoughts?

Thanks.

TwoTired · « **Reply #27 on:** August 24, 2009, 06:31:51 PM »

You need to find out why the plugs don't show the same deposits, before making the same changes to all four carbs.

IMO

What is it that justifies the air screws out 2 full turns?

brett_bike · « **Reply #28 on:** August 24, 2009, 06:33:02 PM »

If they are turned in any more, it stalls when I come to a stop.

TwoTired · « **Reply #29 on:** August 24, 2009, 06:47:24 PM »

Quote from: brett_bike on August 24, 2009, 06:33:02 PM

If they are turned in any more, it stalls when I come to a stop.

That does not justify the setting. It is just compensating for a problem or carb aberrant condition yet unfound.

brett_bike · « **Reply #30 on:** August 24, 2009, 07:03:25 PM »

So what it sound like is I should remove my carbs and start from square one. Not really looking forward to taking the carbs off again but, I want to get this thing running right.

Spanner 1 · « **Reply #31 on:** August 24, 2009, 07:45:40 PM »

At this point I'd double-check the valve clearances ( cold ) as you may be losing compression with valves not seating freely...esp #4...( sootiest plug ).....IMO.

TwoTired · « **Reply #32 on:** August 24, 2009, 11:55:43 PM »

It would certainly be good to be assured that everything else on the engine is adjusted to spec before final scrutiny on the carbs.

The plugs don't look that bad aside for the one on the far right. How long were these run and at what throttle position?
Which cylinder did the black one come from?

There have been some casting issues with the 627b carb I've encountered regarding the main jet mounts on # 1 position. Don't know why but they were commonly corroded which made the main jet seal problematic. If your black plug was from #1 cylinder, maybe you could examine that more closely?

Next is the air jets and the passageways to the respective emulsion tubes. While I haven't encountered it, Hondaman says these passageways can corrode and impede air ingress. This scenario certainly fits your "running rich" complaint, and might be a reason why you have to open the air screws as far as you do. Maybe the air passageways in the carb for your sooty plug is worse than the others? May have to snake a wire through there, or give it a lemon juice or vinegar bath/flush.

I don't recall. Do you have new orings in the carbs for the main jet and the float valve seat? Are they sealing properly?

Things to check....

Cheers,

brett_bike · « **Reply #33 on:** August 25, 2009, 05:46:50 AM »

1. I'm going to recheck the valve lash in the #4 cylinder, that is the one with the black plug.
2. the plugs were run about 200 miles, about 60% freeway miles.
3. Dirty plug is from the #4 cylinder.
4. All new Honda O rings in the cabs.
5. Will pull the carbs off again and check everything.
6. Beat my face against a wall.

brett_bike · « **Reply #34 on:** September 03, 2009, 08:14:33 AM »

Well, I finished beating my face against the wall long enough re-check all the carb settings. All is set at stock (minus the Mac 4 into 1) yet I am still sputtering at less that 1/4 throttle. Maybe my old plugs are contaminated from the black soot on them(is that possible?), so I'll install new ones and re-check.

What am I missing?

Holy frustrating Batman.

brett_bike · « **Reply #35 on:** September 03, 2009, 01:37:26 PM »

Update...
New plugs checked all the adjustments-still no love. Plugs are black soot again, time to try #38 slow jets.

JRK5892 · « **Reply #36 on:** September 03, 2009, 02:19:13 PM »

man i am about to be with ya! i got a CB500 all stock but running a 4-2 exhaust... have not started to tear into it but i will soon for the wife... hope that you come out on top wiht your scoot man.

brett_bike · « **Reply #37 on:** September 03, 2009, 02:49:18 PM »

Thanks JRK5892, this bike is making me crazy. In theory this should be easy, fire, air and compression in the correct amount...Go. Not so much. I've tried leaning out the mixture by lowering the needles, nope. I've had the carbs off the bike so much this summer that I could rebuild them with my eyes closed. The boots can't take much more of this, maybe I'll go to pod's. I'm already having problems, maybe that is the answer.

steamnjn23 · « **Reply #38 on:** December 14, 2009, 11:27:09 AM »

following this thread.

what was the outcome?

brett_bike · « **Reply #39 on:** December 14, 2009, 05:44:04 PM »

Sorry, I sort of forgot about this thread with Denver being in a deep freeze the past few weeks. So to follow up...

New plugs (still a tad rich, but not as bad as before)
Installed a large single K&N air filter that attaches to the air plenum for better breathing (trying to match the easier breathing Mac 4 into 1 exhaust)
All carb setting are stock

I will try to get a pic up in the next day or two showing my air cleaner setup.

The worst part is that just before it started snowing, it was running better than It has for me yet. Can't compare to new but it was pulling pretty eff-ing strong. Took her for a ride up Deer Creek canyon and dodged ice on the street on a few of the turns on the way to Morrison. Good times.

Tnutz · « **Reply #40 on:** December 14, 2009, 07:51:00 PM »

i stuck with a stock airfilter. i found with a higher flow filter or non at all the bike had flat spots...so i bought an oem replacement and all is well.

Deltarider · « **Reply #41 on:** December 14, 2009, 11:15:20 PM »

Quote

so i bought an oem replacement and all is well.

Yeah, hear, hear, hear...

yozzie · « **Reply #42 on:** December 15, 2009, 05:53:21 AM »

I had the same problem on my 500. Stock air box with stock filter, put a 4 in to 1 exhaust on because the old one was rusted out. Found that the bike had a flat spot at 5000rpm when accelerating at 1/4 or so throttle. Lifted the needles a few positions to see the result. Flat spot gone, but had the same "blubbering" or rich running condition at idle to 1/4 throttle. Had to blip the throttle a few times to clear the engine before I could take off. Used a color tune plug to see if I could clear it up with the air screws, no luck, too rich. So I dropped the needles one spot, repeat, and repeat. Runs great now.
Just take your time, change ONE thing at a time to see the result, write it down if you have to. People seem to panic and change ten things at once and then can't figure out what did what. Just my two cents.

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