Fitting a 34mm Petcock on a 44mm tank

I have seen some mention of this on here in the past but no details with finished pictures.

Here is how I did mine.

Bought a good used Yamaha 660 Raptor manual petcock and took it apart to clean it up. Made a adapter plate out of 1/4" 6061 aluminum, laid out the 44mm hole centers then laid out one hole for the 34mm petcock mounting. Drill thru two holes for the fuel pipes. The leading hole for the 44mm is for a flat head bolt - see picture.

 

The trailing edge of the opening for the fuel pipe must be opened up (this is on a KZ650 gas tank) and that is pretty easy to do.

That pictured showed a rubber gasket but the material was wrong and it leaked, I replaced it with a paper gasket.

 

I had to fill in the top of the flat head screw with RTV to get a leak proof seal. Then another paper gasket for the actual petcock base.

 

Here is how it looks with the carbs and air box fitted. The adapter plate makes it sit back towards the air box but it does not hit it. I used a spring around the fuel line to support the bend required to route the line under the tank. It works just fine this way and no leaks.

 

The adapter plate is relatively easy to make, getting it to seal was a bit tougher to figure out.

one thing you could do, is add an oring under the head of the mounting hardware (adapter plate).

years ago, I purchased petcock adapter plates for my XS1100, and that's how they do it.

Hey pal,  I'm not seeing the second 44mm mounting bolt, is it hidden under the base of the 34mm petcock 

If you look at the first picture, you can see what he did. The screw to the right of the petcock is long enough to go through the petcock and the adapter plate and into the threaded bung in the tank. The screw just to the left of the petcock is much shorter and threads into the adapter plate. The screw on the far left goes only through the plate and into the bung. Its head is covered with silicone, so it is not visible in the last picture, but you can see the silicone over it. 
I would be concerned about the fuel eventually dissolving the silicone and leaking past the screw again.

Bought a good used Yamaha 660 Raptor manual petcock  

For anyone else looking to do this. New OEM Yamaha petcocks can be found on EB in the $25 to $35 range & made in Japan.
Yamaha Raptor. Yamaha Grizzly. and one or two more. Item # 322996013249 for example. this one is more squat than the one above.
Some new for less than $20 are probably made in china. no thanks.

ps: nylon washers might stop any leakage. that's what Kawasaki did on my motorcycle. I guess they're nylon.

BlackEyeCafe wrote:

Hey pal,  I'm not seeing the second 44mm mounting bolt, is it hidden under the base of the 34mm petcock 

 

The first picture shows the far left bolt at 44mm, it is a countersunk flat head bolt that is hidden by RTV and the petcock gasket - It is in the text I wrote, guess you did not read it.

As for the leaks, if do get any leaks in the future I will redo the silicone and possibly use 3 Bond or a more permanent solution would be JB Weld. So far after 2 years no leaks.