Topic: ignorance is bliss........

[welnamark]

TwoTired....

I'm just replacing them because i suppose it doesn't get any cleaner then new.  I'm hoping to only take the carbs off once.  At least this year.   

I found the pilot jets at Sirius Consolidated Inc.

http://www.siriusconinc.com/search/show_result.asp#

-mark

[welnamark]

Do you think I should have gone bigger?

[Gordon]

TwoTired....

I'm just replacing them because i suppose it doesn't get any cleaner then new.  I'm hoping to only take the carbs off once.  At least this year.   

I found the pilot jets at Sirius Consolidated Inc.

http://www.siriusconinc.com/search/show_result.asp#

-mark

IMO, it doesn't get any better than clean, stock jets.  After market carb parts can (and often do) have slight differences when compared to OEM parts, so if you have the original jets, it's best to stick with them. 

[TwoTired]

TwoTired....

I'm just replacing them because i suppose it doesn't get any cleaner then new.  I'm hoping to only take the carbs off once.  At least this year.   

I found the pilot jets at Sirius Consolidated Inc.

http://www.siriusconinc.com/search/show_result.asp#

-mark

The pointer just gets me a microsoft SQL error message.  So, I can't tell what you bought. But, I assume they are Keyster kits.  No direct experience with these.  If mine were corroded or damaged, I'd use replacements.  Otherwise, cleaning the ones I had now would be a better option.  There have been reports of issues using after-market parts not subject to Honda quality control.  Are you going to measure the orifice diameter before installing them?

It's a safe bet the carbs worked well enough when driven of the Honda floor.  And slow jets don't wear appreciably by have fluid pass through them.  Carb cleaners do a fair job of removing foreign matter that can accumulate in 30 years.  Why, with your totally stock bike, do you think a larger slow jet is required when Honda engineers did not?

Besides, I have the same bike in my garage working well with the original #42 slows.  With those jets clear and proper choke adjustments, I don't see why your bike should be as cold blooded as you describe.  Shouldn't be any different from mine.

Suit up, get on, pull the choke knob all the way up, start up, Find a new choke position that keeps it running, and drive off.  As it warms, nudge off choke incrementally as you drive, until it is all off and will idle at about 1050 RPM.

Do you need instructions for carb removal?  You have to bewary about those rear rubber couplers.  You can't buy new replacements, anymore.  And, they can easily be damaged during the carb removal and installation process.

Cheers,

[welnamark]

TwoTired......

I wasn't considering changing the pilot jet size originally.  I just figured it might be easier / better to install new than to worry about getting the old pilots perfectly cleaned.  I assumed that when you asked me why i was replacing the original #42 pilots with the same size that you were implying that a larger jet might be a viable option.  Now I assume that you were merely asserting, as Gordon did, that there is nothing more desirable then clean OEM jets.

I will stick with trying to clean the original pilots rather then replace, like you and gordon recommend, unless they are corroded or damaged.

I've taken the carbs out of my prior cb550, the memory of which is primarily the reason why i've been putting this job off for so long. 

thanks again all.

-mark

[welnamark]

I'm back with a report and only one bloody knuckle.  As always there is good news and bad news.  The choke idle advancement cam system was not adjusted correctly and therefore not functioning contributing to cold starting difficulties.

The carbs were not synchronized well, even by bench standards.

The insides of the carbs seemed extremely clean (must be all that seafoam i run through them).  That's not to say that I didn't dislodge some gunk from somewhere in the idle circuit but i certainly didn't see any gunk and all the jets were squeaky clean.

When i put the carbs back on it fired right up on full choke, I backed the choke off to half after about 10 seconds, and totally off choke after another minute and it idles near perfect at about 1200 rpm.  The cold blooded / idle problem seems to have been solved!!

The BAD:

A leaky float bowl.  I figured it was likely that i had pinched a bowl gasket, so i removed the bowl while the carbs were still installed and refitted.  I've always had trouble getting the bowl screws tight enough with the carbs installed so overtightening wasn't really on my mind and I stripped a bowl screw hole.

So the carbs need to come off again.   

I've done some research and it appears that others have drilled out the offending hole with a 11/64 bit and tapped for a m5 x 16 screw.  Can anyone confirm this info or advise about this procedure.  I've never tapped before.

Again, I'm working on a 78 CB550K with PD carbs.

It always seems for me that working on my bike consists of trading one problem for another.......

It sure does run nice now though.......

-mark

[Rdkng]

I was just looking for the fix for the same problem you had.  What is the choke cam and how do I make sure that it is set up right.  My bike is also a 78 cb550k I love it but it won't idle I hope you can help me with this problem.  My wife is worried about my mental health. thanx

[welnamark]

Rdkng,
If you take off the fuel tank and operate the choke you'll be able to see how the choke idle advancement cam works.  There is a lobe or cam at the base of the hinged lever that the choke cable attaches to between the center carbs.  When the choke is fully engaged the cam should "bump" an adjustable screw that advances the idle slightly.  Once you see how the system works pull the choke cable a couple of times while watching the idle set screw.  The flat rest on the idle cam should just barely come off the idle set screw with the choke fully closed (I'd guess a millimeter or 2).  On my bike this results in an idle of about 2000 rpm when the bike is on full choke.  I'm not sure what the spec is for this though......Maybe others will chime in. The set screw for the choke idle advancement is fairly easy to adjust with the carbs on the bike with a short flathead screwdriver.

If you're not getting an idle advancement on full choke this system might be out of adjustment.  It certainly helped by bike with cold start.

-mark

[welnamark]

I got the new float bowl gaskets in, replaced the float bowl screw with allen heads, and reinstalled the carbs last night.  The bike's starting and idling is much improved and I have no fuel leaks.  The tap seems to have been successful.  I think the engine would still benefit from a vacuum synch as I still have some clutch rattle but I consider the project a success.

Thanks to everyone who contributed.

WHAT I LEARNED:

Be careful with overtightening float bowl screws (or any screws for that matter).  A stripped thread adds alot of work to any job.

On carb installation watch that hinged choke lever (where the choke cable is attached to the carbs).  If it's down when the carbs are installed it's impossible to get it back up (where it needs to be) with the airbox installed.  I didn't realize that mine was down untill i connected the choke cable (which i did LAST) and had to take the carbs out again!!  It's also much easier to attach throttle and choke cables before the airbox and battery tray go back in.

I will never remove float bowls again without new gaskets.  It's not worth the trouble.

[Frankenkit]

welllll as long as the rubber gaskets are NEW and not 30 years old, they should be fine for reinstallation, that's why they're rubber.