Gregory Bender

Petcock alternative

Moto Guzzi V700, V7 Special, Ambassador, 850 GT, 850 GT California, Eldorado, and 850 California Police models



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Based on recommendations from Charlie Mullendore of Antietam Classic Cycle and Greg Field, I decided to swap out my existing stock petcocks for petcocks from a small block Guzzi and adapters to work on the loop tanks.

I had a number of reasons for doing this...(1) tired of trying to get my petcocks lined up properly with shimming washers (2) tired of not having a real reserve (3) tired of worn out internals seals - although the latest set of Viton seals from Bruce Giller have worked very well.

The small block petcocks are nice units. They have three settings on both petcocks: Off/On/Reserve. They are mirrored right to left so it is easier to remember which way to turn the petcocks to make them function how you want them to. Operation is smooth.

The adapters are machined stainless and are of high quality. The threads that mate with the tank are quite long for a good fit. Instead of a fiber washer, I used a 12 mm aluminum crush washer to seal the adapter to the tank. Nice stuff.

The petcocks come with small filter screens that screw into each petcock. When secured to the adapters, the filter screens no longer fit. Using a tip from Greg Field, I cut off the plastic bottom of each screen close to the screen material and then used J-B WELD to secure the screen to the top of the adapters.

I purchased the adapters and petcocks from Moto International [now out of business]. I believe the adapters are a Moto International exclusive.


The adapters are no longer a Moto International exclusive. MG Cycle now sells them as well.

The MG Cycle adapters are internally threaded on the end that fits into the tank. These threads accept the stand pipe filters from the original Eldorado petcocks. Very neat! My J-B WELD of the filters to my adapters didn't last very long at all.

Since you are replacing your petcocks, it is very likely you will not have original stand pipe filter that you can fit. Not a problem, as Bob Rappazzo explains:

You may already be aware if this, but I've found a real good set up for filter screens when using small twin petcocks with adapters for loop frame tanks. John Chicoine sells real nice stainless standpipes for the original style Eldo petcocks. They screw right into the adapters I bought from MG Cycle. This is a way better set up than J-B WELDing the plastic standpipes to the adapters. John charges a reasonable USD $20.00 for a set of standpipes shipping included.