Pumper Carb adjustments... Any of you have it mastered?


I'll make this quick as I don't have much time (I'm at work). Or much needed info about specifics.

My dilemna is that I have the 'Eddy' pumper on my 650 (and I'm a rider, not a mechanic! :lol:)... and recently it's been great. However with the new motor mods, and clean filter :D, the opened up airbox/sidecover screen... and misc other things, I seem to need a small adjustment. :lol:

When decellerating, I get a pop. Not a huge backfire... but a little bit of them as I slow down using the motor as a brake. I forget if this is lean, or rich. Lean seems to come to mind.

Also... when I nail the throttle from idle, it'll barely stumble. But just past that point it runs like a champ. Or when I'm hard on it through the gears I notice it runs best at the higher RPMS... lower it seems to not have so much umpfff! It's missing that off idle snap. :devil:

Okay, so let's see.. :awww: I don't know my needle size but I can tell ya I have a airbox/sideplate mod, no restrictions, a mild cam (this was the latest change to the bike), and all stock but unrestricted components otherwise. :thumbsup:

Any ideas Carb gurus?!?! :D:lol: :lol:

not a guru :thumbsup: but here is what i would do - as for the popping start richening it up 1 click at a time(clockwise) till the popping goes away - and for the pump start at 1 1/2 turns out and play with it a 1/4 turn at at time (in or out) i do it by snapping the throttle till you get the dead spot out :devil:

this is what i did - and i ended up at 12 clicks out from full rich and 1 1/2 on the pump :awww:

my bike is stock, uncorked, HRC tip, drilled out airbox

jeff :lol:

A little popping upon deceleator is normal, but if you're getting a lot of it, then turn the adjuster on top two clicks clockwise. If WOT performance is better and popping is less, then you're a step in the right direction. As far as the AP, you can adjust this with your engine running (if you're careful). Get a small box wrench out and a standard screw driver (flat blade). While holding the screw driver in the pump screw slot, loosen the holding nut but keep the AP screw in position. Now turn the AP screw 1/4 turn CW and lock down the holding nut while keeping the AP screw in position and go test your bike. If the off idle throttle response is lazier, then turn the screw the other direction 1/4 turn and see if its any crisper. Once you find a range where the off idle response is really, then make adjustments in 1/8 turns to further dial it in. When you've got the pump set correctly, the off idle throttle response will be immediate when the engine is under a load. You've got the older version of this carb like me as we bought them at similar times from what I recall. You'll end up somewhere around ~1.5 turns out on the pump screw. If you screw in the pump screw all the way CW to find out how many turns out you currently are, do it gently so you don't damage the seat. If you adjust this while the engine is running or while its hot, be careful with your riding gloves because its easy to momentarily touch the header pipe when adjusting this :thumbsup:

You are right--popping is lean. rich it up a click or two. right is rich. make sure the throttle is wide open when you click it.

after thats done see how it hits--if its still stumbling adjust the pumper (screw on bottom on right side) -- 3 1/2 out from full closed is the norm. try it in 1/4 ot 1/2 turns. both to little squirt from the pump, and to much squirt from the pump will do what you are describing...its easy and you should have that nice 'hit' again...although your cam -- if its a big one - will make less power on the bottom and more on the top -- plus your pipe if changed will affect things as well...

also make sure the pumper needle is still there if you have opened it up as they are small and do fall out sometimes...

I got this from Mike on 650R.net too!

Okay... Here's what I found so far;

I ran the needle adjuster in 2 clicks at a time from 13 out. It never changed until I was more like 1 click out. And then it began to run rich... really rich. But the issue of the dead spot on snapping the throttle was gone. I adjusted the pump a tad too... to see if that was where I was way off. I think it was at about 1.5 to 2.5 full turns out.

So at idle with the needle adjuster at about 8-9 clicks out from full tight... it runs, but runs rich spitting some black smoke. However... the dead spot is gone.

Now I'm headed back out to adjust the pump screw in to 1.5 turns out (starting from there). And will play with that for a minute or two... (I'm suuuuuper impatient with this stuff) If that doesn't change anything I'm gonna pull the needle to see what size I have. I remember buying a couple from Barnums, but don't remember what I ended up with. :thumbsup: (Guess it's time to right these things down huh?!) :devil:

I DO HAVE in my hand (process of elimination) - 15E 17E 19E

(the only one with any wear is the 19E it looks like. So what do I have in the carb?) Hmmm...

with that info... what's your take?


I took her apart. Or actually the carb off the bike and found only a tiny squirt of fuel would come from the pump tube. Hmmm... I looked further and noticed more dirt and material around the pumper diaphram. When I really got down to it, I see the brown diaphram may have a pin hole in it. I'd be able to squirt fuel from it and not the brass tube in the carb. But it's not too apparent. I mean, it doesn't stare ya in the face. And it's so slight the fuel almost dries before you can find the spot. It seems like it's enough to keep it from priming or pressurizing.

Hence the no squirt into the carb, and the dead spot when the throttle is stabbed.

I'm calling Eddel now to order parts. :thumbsup:

After calling... talking to Jason, he said to look at the needle in the bowl, and that it may be 'stuck'.

I'll be checking it now. :awww:

Man... these carbs are great, however they sure are finicky over a stock vacuum carb. :thumbsup::devil:

Jason at Edelbrock says, "that's not it... it'll still pump fuel normally. That's just a dust shield."

Now... after even more investigation, I noticed there is a small 1/8" round by 3/8" long dowel missing out of my bowl. It's supposed to also regulate fuel. Jason mentioned that it may be stuck... uhh, stuck? No, how about not even in the hole??!!

That darn Mex gas sure eats up metal components! :devil: j/k'ing! Now I'm beginning to wonder how long it's been missing. I've only ridden the bike a few times in 10months... the other times (ahhhh, you all know the story. :awww:

I'll get a new diaphram, rod, and misc parts from them on Monday. Hopefully this will fix it. And I looked... it's an 18E in the carb for a needle.


I'm not sure where you are Alt wise but is that the needle it came loaded with when you bought it? Also I think I remember reading that from the factory its 2.5 turns out from full in? Ok just to check myself I pulled this up

Hey DWD.

I would be glad to give you info about your carb or anything ells that you may need help with. I will try and make a fast suggestion to you right now .

First thing that you should do is check and see where you are with the click settings.All settings are done from full rich "that would be all the way to the right" Then count counter clockwise you should be around 12 to 14 clicks out to start.

The second thing that you should do is set the pump screw 2 1/2 turns out from full in. Too much pump and the bike will bog not enough and it will do the same but when you have to much pump the bike will not have good bottom to mid power and feel slow. If you do not have the side panel open you will not recive the most out of the carb it needs air flow. This is a mod that I strongly recomend to you.

If I was you I would lean the carb clicker untill it felt good up stairs if you have to be out on the clicks say around 25 then you will need to go to the next leaner needle and then have a richer setting. The same goes for the other way if you richen it and it runs better up stairs then go to the next richer needle. This is a fast way to check out what the motor wants. This is the same for any carb not just Edelbrock carbs. Buy the way the carb should come with a 19 or a 17E it depends when you perchased the carb. If you need more help please feel free to call or email me Thanks...

...we'll stop there but it can be found at Edelbrock tuning, please help

Anyway When I screwed with the pump on my own and messed it up I went back to 2.5 out and it works well in woods where I love the low end snap!! I'm sure if I spent an afternoon working with it I could fine tune it but I'm too impatient for that, too! :thumbsup: So I guess basicly try b/w 1.5-2.5, (I don't have open airbox either)


I bet that brass valve is stuck in the bottom of the hole-and that it just looks like it is missing.

Thats happened to me 3 times...i even went to the point of calling Rob Barnum for ideas--when-sure enough-the vavle was simply stuck in the bottom.

Take a closer look, and try tapping the carb upside down to get it to come out...

Well... since I forgot to order the part today anyway, I'm gonna go and spray some WD or something in the hole. Let it sit and see what happens. Jason at Edelbrock told me to do that anyway... so we'll see.

It just seems when I put an allen head down the hole, that it contacts a sort of hole with a beveled edge. Like as if it was drilled then countersunk. Which made me think something was missing.

We'll see. I'm gonna spray it now and will try it later tonight.

Thanks Mike, I see your able to post now. :thumbsup:

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