Whoa... what the heck is going on now....  :dunno:

The bike has lost ALL power below about 4k RPMs. This problem did not exist before installing the pingel petcock....

Floats? Jetting?  

The bike's at the shop currently.

The current jetting is bone stock ( it's a 1989 ), and I've been trying to search for recommended stock jettings.... without much luck.

So what are the recommended settings?

The bike has zero aftermarket on it aside from the pingel petcock.

This makes the bike really difficult to scoot around town, as I have to rev well above 4k just to take off from a stop.

Are the hoses connected correctly to the carbs? Are you by-passing the frame mounted valve?

Ahh, yes.

Should have mentioned that.

The frame petcock is out of the picture. It goes straight from the pingle outlet, into an inline filter, and into the carb inlet.

Quote from: TheMasterRatAhh, yes.

Should have mentioned that.

The frame petcock is out of the picture. It goes straight from the pingle outlet, into an inline filter, and into the carb inlet.

Did you cap the vacuum take-off that used to go to the stock petcock?  That air leak might cause a significant part of your problem.

Quote from: mjm

Quote from: TheMasterRatAhh, yes.

Should have mentioned that.

The frame petcock is out of the picture. It goes straight from the pingle outlet, into an inline filter, and into the carb inlet.

Did you cap the vacuum take-off that used to go to the stock petcock?  That air leak might cause a significant part of your problem.

Yup, capped that with a 3/16" cap IIRC. Tight fit, but I figured tighter certainly couldn't hurt anything.

Perhaps the process of switching petcocks at the fuel tank resulted in some dirt / rust at the bottom of the tank getting washed down the fuel hoses?

If that happened it could clog up your pilot jets and cause what you're seeing at low RPMs.

:dunno:   :dunno:

Yep, that is what I was thinking about. I just went out to look at my setup. The vacuum port on the carb needs to be capped.

Quote from: KerryPerhaps the process of switching petcocks at the fuel tank resulted in some dirt / rust at the bottom of the tank getting washed down the fuel hoses?

If that happened it could clog up your pilot jets and cause what you're seeing at low RPMs.

:dunno:   :dunno:

Hey Kerry, LTNS. hehe.

The tank has already been cleaned and sealed ( damned if I can remember the name of the product that I used to seal, begins with a P? ) a few months back, so no worries about rust there.

And btw, the problem with the bike passing emissions ended up being emissions hires morons... They were testing it as a car.... four times.  


BBIAB ppl... Being forced into an early lunch. lol.

Quote from: TheMasterRatThe tank has already been cleaned and sealed ( damned if I can remember the name of the product that I used to seal, begins with a P? ) a few months back, so no worries about rust there.

I believe you, but I'll bet at the end of it all you find a dirty jet or two.    

Quote from: TheMasterRatAnd btw, the problem with the bike passing emissions ended up being emissions hires morons... They were testing it as a car.... four times.

I don't suppose they refunded you for the pain, suffering, and GAS?  :x

Quote from: Kerry
I believe you, but I'll bet at the end of it all you find a dirty jet or two.    

LOL. Well, if it makes you feel any better I have talked to the shop and there aren't any dirty/clogged jets.

Quote from: KerryI don't suppose they refunded you for the pain, suffering, and GAS?  :x

hahahahahah. Now that's funny... No, of course they didn't. Oh well.

I don't suppose there is any reason to suspect a change in the float height(s)?  According to Srinath, too high = rich  ( = stumbling?)

Nope, no real reason to suspect the float heights ( what could cause them to change anyway? )  Just a hunch.

I really have no idea what the problem could have been caused by.. All I did was install the pingel.  Didn't even touch the carbs.  And even then, before I installed the pingel I was running straight to the carbs on the stock petcock.

Oh, btw... the pingel with on/off/res positions has some clearance issues for the selector lever on our bikes  

Where did everybody go?  :lol:

Out for dinner, actually.  

Well, I've said my piece, but I'll say it again.  Especially now that I understand you were already going straight to the carbs with the stock (fuel tank-mounted?) petcock:

* Your electrical system didn't change, right?  Must be the fuel system.

* Leaving out the carbs for a sec, your fuel delivery system has only a few parts: the fuel tank, the attached petcock, and the lone fuel hose.

* I assume the fuel hose didn't change.

* Your vacuum caps didn't change (or did they?)

* The petcock was swapped for a Pingel, which should only improve the flow.

* The fuel tank didn't change.

*** That leaves the carbs. ***

* Your original post stated that the bike doesn't run well below 4000 RPM.

* I infer that it runs OK

above 4000 RPM.  That would pretty much render the  fuel delivery analysis above ... useless.    No, let's say obvious / trivial / not worth bringing up.  (Sorry!)

* The carbs haven't been wrenched on, haven't changed externally.  Hmmm, what could possibly explain the Dr. Jekyll / Mr. Hyde behavior on either side of the 4000 RPM boundary?  The only thing that comes to mind is jetting.

* But the jets haven't changed either!  Or have they?  The mains sound OK, but the pilots ... ah, the pilots!  Those things can be clogged by the smallest solid particle, or build-up of gunk.

* Particle, eh?  Hmmm ... rust?  No, the tank has been de-rusted.[/list:u]
Assuming that the fuel hasn't had time to turn to varnish, the only answer that makes sense to me is that some kind of dirt has clogged one or both pilot jets.

"But, where would such dirt come from?"

* Have you ever filled your fuel tank when the wind was blowing?

* Have you heard about not visiting the gas station right after the tanker has refilled the underground tanks (because that stirs up the sediment in the tanks)?

* Why would anyone install a fuel filter if all gasoline were 100% "pure"?

* And isn't there even a

slight chance that changing the petcock could involve tilting the tank back and forth, allowing some of the "dregs" to get into the fuel hose?[/list:u]OK, I'm done.

Let us know what you come up with.  I won't mind if I'm totally wrong, I just like to know....  

It sounds stupid, but did you check how well the fuel flows from the Pingel petcock? maybe a gasket partially blocks it or something, causing the carbs to fill up very slowly. My bike kind of reacted the same when a fuel line was kinked. It stuttered below 5000 rpm, then took off.