Topic: pods 4-into1 with idle surge VIDEO POSTED help

[b5rider]

I.assume this is the crankcase breather. Should smoke be coming out of it?

[b5rider]

here is a link to the video I made today

[DaveBarbier]

OOOH, OK. Thanks
anyone know the size of the screws/adapters I might need?
Also, where would I find the air mixture adjustment screw on these PD carbs?

thanks!

The adapters are M5 .8 pitch. They should come with the carb sync tool like the MotionPro Sync Pro, for example.

On these carbs there is only an IMS which controls the amount of fuel. They don't have an air mixture screw.

As for the video, I see the surge. Mine was a lot worse. Sync the carbs like Cal suggested and report back.

EDIT: I think it's normal for the crank case breather to smoke a little. I'm not certain, though. There's always blow by past the rings which makes it's way out the breather. Normally that hose is routed back into the air box for re-burning. But for those of us with pods have to add a filter like this or something similar.

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1978 Honda CB550K

[b5rider]

Thanks Dave. Where is the IMS screw located?

[DaveBarbier]

The idle mixture screw is a brass knurled screw underneath the carb body set in with the bowl. You can't see them in your pictures. In for lean, out for rich. Blip the throttle after each half turn.

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1978 Honda CB550K

[flybox1]

Thanks Dave. Where is the IMS screw located?

#4 in this picture is the IMS/air fuel mixture screw.....

http://forums.sohc4.net/index.php?topic=137858.0

[b5rider]

Found it. If I get the carb tuning tool that looks like a long screwdriver with a bent tip I wont have to take the tank off, right?

[flybox1]

ok...you have confused a few screws 

the IMS, which you are pointing at in the above picture, adjusts the air/fuel mixture while the bike is at idle.
Your IMS needs to be set per the manual, if you have the stock intake and exhaust, and then left alone (for the most part)

the carb sync (vacuum) screws, near the top caps of your carbs, adjust carb throat vacuum.  they do not adjust air or fuel supply
The vacuum screws you will adjust when you are doing a carb sync, and yes, you'll have to take your tank off for this.....

[b5rider]

Ok, thanks.
So, sync carbs first or adjust the IMS settings?

[flybox1]

The 1-1/2 turns are on the screws under the bowls per Flybox's picture. The knobs Dave refers to are under the bowls that you're pointing to for adjusting during the vacuum synch.

calj737...these are one and the same

if you have a stock airbox, filter, and exhaust, there is no need to adjust the IMS during the vacuum sync if they are set to stock settings.
set them and forget them.
Use the vacuum screws with the long screwdriver tool to adjust the vac sync screws during your carb sync...these screws are NOT the IMS, they are on TOP of your carbs. 
IMS are on the bottom, #4 in the picture i posed and pointed at by you in your last picture.

[flybox1]

vacuum (slide) adjuster(sync) screws as indicated by yellow lines in these pictures.
http://forums.sohc4.net/index.php?topic=110114.msg1234181#msg1234181

[rb550four]

but he has pd's

more stuff
http://images.cmsnl.com/img/partslists/honda-cb550k-1978-usa-carburetor-components-78_bighu0056e431801_09ce.gif
some hints
http://forums.sohc4.net/index.php?topic=5608.0
  still looking for a tutorial with pictures

[b5rider]

OK. On my '78, I have the PD carbs, which have an internal vacuum set screw. It would be the top screw in the picture with the locknut, correct?

When I sync the carbs, do I need to put the caps back on while making adjustments?

Also, I backed the IMS screw out to 2 full turns to remedy what I thought was a lean idle (causing the intermittently high idle), but the high idle continues.
Just waiting for the adapter tubes to come in the mail from Amazon and I'll sync them

[rb550four]

I just saw this....even more to chew on.
http://forums.sohc4.net/index.php?topic=124332.0

and of course, put a fan in front of your machine while syncing so it can stay cool while you dial it in.

Sorry, couldn't find the tutorial with pictures.

[flybox1]

OK. On my '78, I have the PD carbs, which have an internal vacuum set screw. It would be the top screw in the picture with the locknut, correct?  CORRECT

When I sync the carbs, do I need to put the caps back on while making adjustments?  NO...they need to be off to make adjustments of the vacuum screws based on what your vac sync tool is telling you.

Also, I backed the IMS screw out to 2 full turns to remedy what I thought was a lean idle (causing the intermittently high idle), but the high idle continues.
Just waiting for the adapter tubes to come in the mail from Amazon and I'll sync them

how do you know its a lean idle?  what do your plug deposits look like?

[mrbreeze]

I'm not a 500/550 guy so I'm not sure where the mixture screws,vac taps,slide adjusters are on these carbs but a couple of things jumped out at me while reading this whole thread.
1. I get the feeling you don't have a manual for your bike. If you are gonna do the work on it you need a book. Its like going out of state to a place you've never been without a road map. You kept asking where this and that were on your carbs. I salute you for doing the work yourself. Lots of people get on here that are scared to death to do their own work. These bikes are fairly easy to work on but when you take them to a shop without knowing anything about the place or the guy doing the work you're just asking to get ripped off. Lots of shops won't work on the older bikes anyway.
2. As already mentioned I wouldn't believe it was synched just because someone told you it was. Especially if it were exhibiting the symptoms you described. I see that Chicago isn't that high above sea level so compared to So Cal. it probably won't be much of a factor. I brought my 750 from Wyoming (5000 ft.) to Modesto (90 ft.) in 2004. Then I swapped it over to pods and 4 to 1 from stock. I had to start from scratch as far as tuning it....jets needle settings, etc. I bought a Morgan Carbtune for $120 and never regretted that decision. One or 2 carb synchs at the shop would cost that much.
   Anyway.....you came to the right place if you love these bikes. Never be afraid to ask questions....there will always be somebody in the know to help you out or steer you to the right place for parts.

[DaveBarbier]

OK. On my '78, I have the PD carbs, which have an internal vacuum set screw. It would be the top screw in the picture with the locknut, correct?

When I sync the carbs, do I need to put the caps back on while making adjustments?

Internal vacuum set screw...is that what it's called? Anyway, yeah it's the grub screw with the lock nut. All it does it raise and lower the slide, increasing or decreasing vacuum. When syncing you have to keep the top caps off, otherwise you won't be able to turn the screw! .

Oh, and just know there are (from what I understand) two types of PD carbs for these bikes. PD46C and PD46A. I am almost certain you have the C like I do. But normally it's stamped right below the PD on the carb body.

What sync tool did you get?


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1978 Honda CB550K

[iron_worker]

Does applying some choke help to cure the idle surging? If so, that should clue you in to the fact that it's lean.

You may not even have enough range on the Idle Mixture Screw with the existing pilot jet to get the proper air fuel ratio you need.

IW

[b5rider]

I'm making my own sync tool
I take the choke off after its warm.

[iron_worker]

Yes as a test you can try applying some choke. If it helps the situation then that probably points to a lean condition being the root cause of your issue as applying choke is enriching the mixture.

IW

[b5rider]

No changes with the choke. Decided to just take it in to the mechanic

[AlekStooge]

I'm going to be rejetting, sync, adjusting etc, my stock 78 PD46C carbs soon. The idle jets have to be drilled out, in order to remove them correct? I was told at the Honda dealership that you leave the idles alone. Despite following Denny Zander's guide for a 4into1 with pods in Chicago elevation telling me go up one size. To change idles or not to change?

[DaveBarbier]

I'm going to be rejetting, sync, adjusting etc, my stock 78 PD46C carbs soon. The idle jets have to be drilled out, in order to remove them correct? I was told at the Honda dealership that you leave the idles alone. Despite following Denny Zander's guide for a 4into1 with pods in Chicago elevation telling me go up one size. To change idles or not to change?

Worst case drill them out, but try pulling them out with pliers first. On both my racks they popped right out pretty easily. Squeeze and pull straight out. Even if you want to keep them the stock size, definitely pull them to be sure they're clean.

My pilots are stock 42 with pods and 4-1. I'm at 500ft ASL.


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1978 Honda CB550K

[DaveBarbier]

No changes with the choke. Decided to just take it in to the mechanic

The carb sync didn't help?


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1978 Honda CB550K

[ANDY W]

I'm going to be rejetting, sync, adjusting etc, my stock 78 PD46C carbs soon. The idle jets have to be drilled out, in order to remove them correct? I was told at the Honda dealership that you leave the idles alone. Despite following Denny Zander's guide for a 4into1 with pods in Chicago elevation telling me go up one size. To change idles or not to change?

the higher u go in in elevation the less fuel u need not more, less air less fuel. Chicago is not that high anyway. stay with the stock size. i tried the next size up, which is a 45, so i wouldn't have to turn my ims out so far. it didn't work. ran to rich at idle even with the ims turned all the way in