Topic: Do I have funky carbs?

[AbbyRider]

I've tried searching the answer to this with not much luck. I've got a set of PD 41B carbs on my '77 750F. At least that's what's stamped on the side. The weird thing is that it's my #3 carb that is the non-adjustable one, instead of #2. Also, they had non-adjustable needles, whereas I thought the 77's came with the grooves. I've since replaced the needles with the stock '77 grooved versions, but am having trouble dialing things in. So just want to be sure I've got the right carbs on this bike, as I've been using the '77 manual for things like float height etc.

Any info anyone has would be much appreciated. Anyone else have a #3 carb that is the non-adjustable one? Or is it possible that a PO switched just the slide assembly from #2 to #3? And if that was the case, should I be swapping it back? Is there anything that would be prevent #3 slide from working in #2 carb? And vice versa? I was having some plug fouling issues on #2, and it turns out that the emulsifying tube that leads to the needle jet was plugged. Got that cleaned out and then synced the carbs, which is when I noticed the #2/#3 issue. I was just gonna wait for a response before I get things buttoned back up. If someone says I should swap slide assemblies between 2 and 3, I'm assuming I'd need to do sync again?

[AbbyRider]

Here's a shot of the carb stamp.

[harisuluv]

Yes sounds like they mixed up where the #2 goes.  Easy to fix.  I would probably sync again.  After making similar changes I have been able to feel that the sync was changed with a drill bit or gauge. 

So yes, put #2 back

[lucky]

It is very important that the non adjustable carb be in the #2 position.
Set the adjustments (floats) for the CARB model...NOT the year of the bike.

You cannot use the drill bit trick on the 1977-78 carbs. Idle will be way too high.
The slides must be closed all the way when the throttle is off.

When you sync them you will only be raising the slide about .007 thousandths of an inch.  The #2 carb is the "master" carb.

The carbs you are using will be better that the F model carbs anyway.
Question is , do you have the F model stock exhaust?

You WILL need to re sync the carbs after moving the parts to their correct positions.
Here is why:

The 1&2 carbs are joined together with a mechanical joint that is sort of sloppy.
So THAT is partly why that when you sync you are not only syncing all 4 carb idles to #2 but at the same time you are getting 1&2 to match up with  carbs 3&4 that can get off because of that mechanical joint joining the throttle shafts.

Look and you will see.

[AbbyRider]

Yes sounds like they mixed up where the #2 goes.  Easy to fix.  I would probably sync again.  After making similar changes I have been able to feel that the sync was changed with a drill bit or gauge. 

So yes, put #2 back

Awesome. Thanks.

[AbbyRider]

Harisuluv - just looking at my carbs and your definition of easy to fix might be substantially different than mine. Unless I'm missing something obvious? Looks like I need to remove carbs and separate from the rack to be able to get the slide assembly off the rod that runs through the four of them? If that's the case I may keep them like this for a while. I remember when I worked on my 78 carbs how time consuming it was to disassemble and the reassemble.

[harisuluv]

Yes that is correct, when I read it, sounded like you already had them apart, hence it would be easy, but yes, it is a little work to do if they are still all together.