Mikuni RS Carb and Petcock Question

Can anyone tell me if the choke set up should stay "on" when pulled out on the Mikuni RS series carbs (RS 38 flat slides)? If I let go of the choke lever it automatically returns to the "off" position. It seems there should be a set screw or something for tension but I don't see anything. Anyone familiar with these carbs?

Also, on a related note - I am set up to run (2) pingel single-outlet petcocks (one on each side of the tank) but was wondering if (2) are necessary? I would think that one hi-flow pingel should supply enough fuel, but would like some opinions, please. I'm thinking of going down to (1) petcock and using a "Y" to feed both inlets on the carbs. My current set up is 1260cc, 10.5-1 comp, .425 cams, o/s valves, ported head, and obviously a 4-into-1 header and individual air filters. Any thoughts?

Thanks!

Mine do the same thing and I don't know why either.:dry:

Mine do the same thing and I don't know why either.:dry:

Forgive a wild guess -- is it possible the interior tank shape separates the fuel into both sides which are inaccessible to one another at low fuel levels, thereby requiring a petcock on each side to fully drain both sides?

Patton wrote:

Forgive a wild guess -- is it possible the interior tank shape separates the fuel into both sides which are inaccessible to one another at low fuel levels, thereby requiring a petcock on each side to fully drain both sides?

No, but that's a good thought. It's just a stock MKII tank that had a fitting welded onto the right side in the same location as the stock one on the left.

Here's a bad picture, but it's the only one I have...

Damn picture posting!!

Here we go again...



Post edited by: 79MKII, at: 2008/01/13 21:45

kenskz1000 wrote:

Mine do the same thing and I don't know why either.:dry:

Yea, I think something must be missing from ours. Why would they not stay "on". It's gotta be pretty hard to start the bike AND hold the choke on.

Maybe WiredGeorge will chime in...

Nobody using RS carbs? Anyone? There must be a way to lock the choke??

You boy racers are on your own on this one... I don't know a lick about RS series carbs. I am having problems following the problem here... You have to hold the choke on those things manually? That doesn't sound right. Most Mik carb assemblies with an enrichener circuit have either a detent on the choke arm where there is a bb underneath that is spring loaded or if there is a rod with a pull knob, there will be some very small spring loaded BBs under the rod that fit into hollowed out spaces on the back of the rod for a detent. If I had a set of the carbs, I could tell you which type you had but I bet there is a BB missing somewhere because when you take them apart and don't know they are there, they tend to get lost.

My hopes are shattered - I thought you'd know for sure George!

Yea, the problem is that you have to hold the choke on. I realize this can't be right, I'm just not sure what I'm missing. I've gone over the parts diagram and just can't find anything that would hold them open. The RS series do have the choke rod with a pull knob as you mentioned, no lever as is found on earlier carbs. I'll look things over again and try to find where a missing BB might go. Well, thanks for chiming in anyway!

Well, they call the choke rod a "starter shaft". I guess because it's for the starter circuit. Anyway, I was able to find a "spring/starter shaft" and "ball/starter shaft" on the parts list. I'm guessing that is what keeps the choke out. I still don't have a clue where it would go and the diagram is no help at all. At least now I know what to look for. If I can find out where those parts go, I can double check to make sure they are missing and order them if necessary. Thanks for the tip George!

Now, what's your opinion of a single pingel petcock feeding those beasts??

I just bought this ones, is 36mm, but i think they are similar to yours.



Where the red arrows are, with nr 1 and 3, there is a little gap in the underside of the chokerod, and there are a ball inside the carburator pushing on the choke rod when you pull it out.



You can see the little gap/hole in the chokerod if you look closely.

Post edited by: RoyNor, at: 2008/01/15 18:51