Tech Tip: The Truth Behind EMGO Petcocks

Tech Tip: The Truth Behind EMGO Petcocks

The EMGO motorcycle brand is a leading and popular parts manufacture within our classic British industry 

With EMGOs huge manufacturing facility located in Taiwan, EMGO supplies gas tanks, gasket sets, tail lights, petcocks and everything else in between for our traditional Triumph, BSA and Norton motorcycles 

Today, we will be covering the topic of petcocks and why we believe that EMGO petcocks are the best petcocks on the market should your tank accept a 1/4" BSPP (British Standard Pipe Parallel) valve

Lets dive in...

Early-mid 2000's 

Lets take a trip back in time to the early 2000's 

EMGO has been supplying classic British motorcycle petcocks for over 20 years, however, there petcocks didn't always receive a "positive praise" 

The older style EMGO petcocks would leak and break down in a short period of time causing gas leaks, sealing issues and "hard to turn levers" that would eventually break off  

We even experienced those issues here some time ago which left a bade taste in our customers mouths and even ours 

You might even hear some folks say "stay away from EMGO petcocks"

Although they did have a point years ago, I can safe with confidence that opinions and quality have changed since then 

The problem (then)

So what caused the EMGO petcocks to leak and break down?

It was simple, it turned out to be the internal parts that were not compatible with the modern fuel 

It had nothing to do with the brand or quality, just simply incorrect components for the specific job

Luckily, EMGO listened to the problem and came up with a simple and effective solution that is now implemented on all EMGO British motorcycle petcocks that we stock and that are on the market with other vendors 

Keep reading to find out how EMGO made a better petcock..

EMGO petcock tear-down 

There are 2 major design benefits of the "updated" EMGO petcock that make them pretty dam good and reliable in which we will cover below using an "off the shelf" EMGO petcock 

First lets cover the internal parts followed by the removable filters

Internal metal parts 


Inside An EMGO Petcock


The solution that EMGO came up with to fix leaky petcock valves and "hard to turn levers" was by simply changing the components internally

That consisted of metal internal parts instead of plastic parts that would dry and crack which would cause leaks...

Having metal internal parts would also work with the changing fuel blends that are at your local pumps

This new "updated" design is in fact nothing new, and was implemented around 2010 or so and the same process is still being used today 


Removable filters


Removable Filters


 Unlike some of the leading brand petcocks (and original petcocks) on the market, the EMGO petcocks give you an option to remove the fuel filter should they need to be cleaned or replaced 

The filter features bottom threads while the petcock features internal threads that allow this to be done 


My experience 

 Most of my Triumph's, and some BSA models that have been converted over to the 1/4" BSPP petcocks are running exclusively EMGO petcocks 

My 1968 Triumph TR6R has the "updated" EMGO petcocks which I installed back in 2014 and they do not leak, weep or seep 

In fact, the levers are still smooth and easy to operate to this day (even when the bike sits)

Most of our customers that have installed EMGO petcocks have been happy with the quality and price point 


Current stock 

So from reading above, you heard me throw out the term "1/4 BSPP" a lot 

EMGO only makes petcocks that are 1/4" BSPP for our British bikes, however, not all tanks and British bikes can accept a 1/4" BSPP petcock... 

1/4" BSPP petcocks are popular on most Triumph applications, and some BSA and Norton (also others)..

1/4" BSPP has a thread O.D. of approx .509" with a thread pitch of 19 (straight threads)

Should your tank accept that size petcock, checkout our current EMGO petcock selection by viewing the chart below 


 Petcock type Specs Part # Link
Lever Type 1/4" BSPP X 19 83-2800 Click Here
Lever Type 1/4" BSPP X 19 83-2801 Click Here
Lever Type W/ Flag 1/4" BSPP X 19 60-4511 Click Here
Lever Type W/ Flag 1/4" BSPP X 19 60-4512 Click Here
Sealing Washer Pack Dowty Type 70-7351 & 83-0002 Click Here
Replaceable Fuel Filter EMGO Petcocks Only Click Here


BSA "Ewarts Petcock Conversion"

1/4" BSPP To 3/8" BSPP Adapter

Although this quick paragraph is slightly off topic, I thought now would be a good time to cover our adapters  

BSA (and some Triumph) models that where fitted with the push & pull / pull & turn Ewarts petcocks with a spec of 3/8" BSPP can now use the EMGO "flag type" petcocks like shown above if you use our special adapters 

This "conversion" will allow you to use an EMGO petcock instead of the older Ewarts (cork) petcocks that will eventually leak and fail 

All my BSA singles & twins here at the shop get this "conversion" for practicality reasons 

Should you be interested in an adapter for your tank, please see the chart below

Part Type Specs Link
Petcock Adapter 1/4" BSPP To 3/8" BSPP Click Here
Sealing Washer Pack (Recommended) Dowty Type Click Here



Thanks for reading  

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Like what you read? Click here to read more posts like the one above 

Have something to say? - Feel free to leave us a comment in the section below 

Ride safe! 


  • dale mogenson

    thanks for a great article. this is the type of thing british bike owner love to see to avoid making a mistake with our bikes. this makes your company the place to do business with!!!!

  • Martin Hopps

    Hiya, greetings from England,
    BSPP means British Standard Pipe Parallel, straight thread as you say.
    the other type of BSP thread is BSPT with a tapered thread which uses ptfe tape or pipe sealing compound to seal the thread as opposed to Dowty washers or copper/fibre washers used on BSPP threads.
    Please don’t think I am being awkward, just trying to help,
    regards Martin.
    P.S. keep up the good work.

  • Roy Bills

    I have just fitted a pair of emco petcocks to my 37 Benelli 4TN after failing miserably with the originals. I found that once removing the filter I could removed the copper tube on one side and replaced the filter, this gave me a reserve for a few miles, not much but enough to get out of trouble, hope this helps, Roy

  • Richard Brand

    Thanks guys for taking the time to write this story. I still have a few of thos plastic units in my “scrap for repair” box. The next time I do a rebuild I will definitely order Emgo again from you.

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