Snubber - couldn't make it work.

[BOZ]

Seemed like a good idea, so I purchased a snubber from Chemiquip Products Co. (Brass, 1/8" npt, 12B, HXX) and inserted it in the petcock vacuum line with the proper fittings on each end. It didn't allow any vacuum to the petcock and stopped the gas flow. Just to make sure, I reversed it and still no vacuum to the petcock. Is this the wrong snubber or is there another problem? The petcock (and gas flow) works fine without the snubber in the vacuum line. At this point, it seems to be a wasted purchase for my Valk. Any thoughts?

[John Schmidt]

Boz, I'm a bit confused as to what a "snubber" is, and what purpose it might serve in conjunction with the petcock. Judging by the number of times the post has been read with no comment, I'm probably not alone. Can you shed a little more light on exactly what it is, or is it possible it's a European term we're not familiar with. No harm in that, we just need a bit more to go on.

[Garland]

A snubber is a like a vacuum valve-I have one on the tube going to the vacuum canister on my cruise control. I think he is using one on the petcock to avoid gas running down the tube to the carb in case of a failure in the petcock.

I would think you could suck on either end of the valve to verify that it works and orientation/flow.

[Ricky-D]

The concept of using a snubber in the vacuum line that runs to the petcock is to reduce the pulsation the petcock experiences with the motor running.

The result would be less wear and tear on the petcock diaphragm and a  more reliable and steady stream of fuel to the carburetors.

If you have any experience trying to synchronize the carburetors with vacuum gauges, snubbing the vacuum lines is a necessary step to eliminate the pulsations that cause the needles to widely fluctuate.

Regarding the snubbers, I simply replaced my OEM petcock with a Pingle and eliminated the need for any vacuum hose, Period.

***

[Patrick]

I'm also a big fan of changing to the Pingle petcock.. If the snubber didn't work[I didn't think it would] and you're still concerned about the pulses, then just tie several intake vacuum lines together and run them to the petcock..Almost any auto supply store should a variety of vacuum connectors and tube..

[Larry]

Boz, I'm a bit confused as to what a "snubber" is, and what purpose it might serve in conjunction with the petcock. Judging by the number of times the post has been read with no comment, I'm probably not alone. Can you shed a little more light on exactly what it is, or is it possible it's a European term we're not familiar with. No harm in that, we just need a bit more to go on.

See this thread from a few weeks back:
http://www.valkyrieforum.com/bbs/index.php/topic,7231.msg54893.html#msg54893

[John Schmidt]

I didn't happen to read that post so wasn't familiar with the term. Seems kinda strange after all the years working on various means of transportation.  A Dampner...yes, guess it's a different name for the same item.

[John U.]

I installed dampers/snubbers on two Valks this past spring. They came from McMaster-Carr, and are listed as "pulsation damping snubber with filtering disc, brass, 1/8 npt connections, 0.5 micron, 3000psi",. They cost 8.69 each plus about 5.00 for barbed adapters. They are working fine. Whether they will increase the life of the petcock remains to be seen.

[mikeb]

i am suprised they work at all there must be a way for the vacum to leak off or the petcock cant return to the off state. so that tells me there working more like a dampner than a valve

[98valk]

3k miles on my install, have not had any problems.

did u use teflon tape or similar for the end fittings to ensure no leaks? I also tie-wrapped all hose connections.

[BOZ]

If it works for you, then I must have done something wrong on my install. I'm going to install the snubber again and double check to make sure I've hooked everything up correctly.

Your original idea and follow-up input are much appreciated. Thanks. 

[98valk]

i am suprised they work at all there must be a way for the vacum to leak off or the petcock cant return to the off state. so that tells me there working more like a dampner than a valve

the snubber I used has an approx 3 second delay to bleed down or to open the petcock on initial startup. during shutdown from the intake manifold up into the carb is an open path to atmosphere which allows bleeddown.

[BonS]

A snubber is a non-directional flow restrictor. Any small leak in your petcock diaphragm or associated tubing will turn into a bigger problem when you add a snubber. The limited flow through the snubber may not be much of a match against even a small leak. An HX (1 micron) or G (2-5 micron) will do better against a small leak but will allow greater pulsations so is counter productive to the life of the diaphragm. Eliminating all leaks is best.

[mikeb]

i am suprised they work at all there must be a way for the vacum to leak off or the petcock cant return to the off state. so that tells me there working more like a dampner than a valve

the snubber I used has an approx 3 second delay to bleed down or to open the petcock on initial startup. during shutdown from the intake manifold up into the carb is an open path to atmosphere which allows bleeddown.

same thing i said its not a valve then