petcock bolt spacing

[cutlass79500]

Does anyone know the petcock bolt spacing for a 72 gt380 i believe most of the gt have the same spacing. I have a good used tank headed my way and i am going to try and do something different then a vac petcock. Nothing wrong with them but i have lost a motor due to a leaky one. Plus my gas water heater is in the garage and if it starts leaking and puddles on the floor i am afraid of an explosion. Thanks If not will measure it when it gets here just want to get a jump on it is all

[Coyote]

44mm. 380, 550, 750 All years. Just put a manual on my 78' GS1000. It is also 44mm. Pics in this thread: viewtopic.php?f=2&t=11713" onclick="window.open(this.href);return false;

[jabcb]

A Pingel vacuum petcock + adapter plate is another good but pricey option.

Has vacuum-operated on & reserve.
Has an off position so you can definitively shut it off if you want.
Its also a modern product designed in the era of ethanol gas.

One drawback is that it doesn’t have prime, so some extra kicking will be required if you haven’t used the bike in a while.

[Coyote]

One thing about a true manual like I bought is when you flip it to run, it's the same as prime on a vacuum petcock. This translates to your float needles have to be in good working order. Still critical on a vacuum petcock, but not as critical as a true manual.
I have seen pics of and reference to float needles with Viton tips. What a good idea. Is there a source for those or are they model specific? I guess I could google it.

[Coyote]

Ah Yes. $18 a pop at bike bandit. I see these have the retaining clip. Doesn't that require another part or different seat?

http://www.bikebandit.com/aftermarket-p ... arburetors" onclick="window.open(this.href);return false;

[ConnerVT]

Always replace the needle and seat as a set.

[Coyote]

That is per set. I'm just wondering where the needle retaining clips on / to?

[jabcb]

More info on the Mikuni needle valve assemblies:
http://jetsrus.com/needle_valve_float_b ... ikuni.html

[ConnerVT]

That is per set. I'm just wondering where the needle retaining clips on / to?

Clips on the seat.

[Coyote]

That's what I thought, but I don't see any provision for that in the set I posted a link to. It shows the needle with the clip, but a very standard looking seat.

[ConnerVT]

Not the best pictures, but you'll get the idea. This is how they are in the carbs in my T500:

[tz375]

Coyote, with that style, the clip fits over the tang on the float.

Our FZR400 is like that - probably because the carbs are at such a steep angle on that bike.

Another thing to notice is the size. Sled carbs and bikes with fuel pumps are typically 1.5mm jets. Street bikes are typically 2.00 or 2.5mm and thirsty buggers need 3.0 or larger.

When using sled carbs on a bike without pump, the needle and seat must be swapped for larger. I have drilled them out and cross drilled them in the past for Methanol, but it's easy to get holes that are not round and do not seal.

[ConnerVT]

2.5 on my T500. I would think the same for the triples.

[Coyote]

On the pictures that Conner posted, I see a groove on the seat neck for the large end of the clip. That makes sense - a seat designed for the clip. The link I posted shows a normal seat, but a clip in the needle. That's why I am confused. Who knows? It might be a generic picture.

[ConnerVT]

Those with a clip on the needle attaches to a tang on the float. Pulls needle out of the seat when the float goes down.

Those with clip on the seat is to prevent needle from dropping too far out of the seat.