74 T500 petcock leaking

[RossB]

Just my T500 on the road today the last time it was registered was 1986 went through bike rebuild cards , bearings, tires ect won't bore you! Started right up idle screws cranked in amost all the way in
But does idle ok. Petcock was super clean but find it doesn't shut gas off completely know that cause float sticking on left carb take care of that later. Pulled line,leaking not thrilled with vac system anyway
Could there something in petcock of is that just the deal. Love the bike!

[jabcb]

The petcock is often repairable.

Its likely that the lever gasket is shot. The part isn’t shown on the T500 parts diagram, but its shown on the GT250 diagram.
See part 5, part # 44341-18450, on:
http://www.partzilla.com/parts/search/S ... parts.html

Parts are available from Europe to fix the vacuum side, but they are more pricey.

You could also just replace it with a modern alternative.
Manual petcocks are available from a number of sources.
Pingel has a nice vacuum petcock that’s about $200.

[akendall1966]

You can block off the prime circuit to give you an off position.

[GTandcbr]

Give the tap a quick service
https://youtu.be/qWNyvjaWfz8" onclick="window.open(this.href);return false;

[RossB]

Thank you took it apart today cleaned everything looked really good bench tested it ng. Got a cheap aftermarket to hold me over. Might rebuild it over winter its a nice piece shame to let it go to waste.

[RossB]

Looked at video on service petcock mine has a spring in it go figure?

[GTandcbr]

There are 2 springs in the petcock. One which is the coil type holds the diaphragm shut in the back the other is made of steel and keeps the lever tight to the gasket in the front.

[GTandcbr]

My apologies gentlemen a different tap Need to get my specs on!

[Alan H]

You can block off the prime circuit to give you an off position.

But if you do that, you lose the reserve facility.

[akendall1966]

You can block off the prime circuit to give you an off position.

But if you do that, you lose the reserve facility.

Hi Alan,

No you don't, not on a T500 tap I still have Reserve and run which are fed via the diaphragm valve which I have disabled by removing the spring and putting an oring in the recess in the tap to ensure the diaphragm is held open. The prime circuit bypasses the diaphragm into the filter bowel from the reserve inlet, which I blocked off at the filter bowl end.

There are 2 feeds into the filter bowel, the one nearest the diaphragm is controlled by the combination of petcock lever position and diaphragm valve, the other just the petcock lever position i.e. fuel only flows in the prime position. Block this feed up and prime becomes off, reserve and run switch between the 2 inlet tubes, but with a disabled diaphragm valve fuel flows directly to the filter bowl and onto the feeds to the carbs.

I blew a little compressed air from the filter bowel inlets in the different lever positions to verify which tank inlet was 'in circuit' so I am 99% I still have the benefit of 'reserve' function.

Retained the OEM look of the petcock, but operates like an Off-Reverve-On manual tap.
Happy days

AK

[Alan H]

That's a new one on me. Cheers.

[RossB]

I love you guys thanks!