Noobie Question > What size are the petcock bolts??

[tweekin2]

Good day, after getting my electrical questions solved, it is time to move over to this forum with some pretty simple questions. Please have mercy.

I have a project that came in boxes. I am ready to mount the tank, but I can't find a proper bolt that will screw into the petcock threads.
I just hit ACE hardware, and bought everything the had:
M5 - .80
M6 - 1.0

Various lengths, but the M5 is too small and the M6 goes in about 3 turns and won't go further. Same thing for both threads.
So before I screw up this tank, I wanted to see if there was a resource that shows you bolt sizes. I searched the forums and didn't come up with any info. Also nothing in the service manual.

Once again, a big thanks for helping us beginners not throw money out the window by breaking things!!!

Cheers,
Cory

[Larry D]

Which bike ??

[tweekin2]

78 GS750E > But don't think it is correct tank

Sorry about that- it is a 78 GS750E , but this isn't the correct tank.
The mounting tab doesn't line up in the back.
Is there a part number somewhere on the tank to identify it?

[MisterCinders]

According to the part numbers, that M6 - 1.0 bolt should work for the GS 750 tank.

If you have some other tank, the threads in the tank are the issue. Are you sure it's a Suzuki tank? Post some pics and someone here can identify it. Could be a later model year's tank, in 1980 or so they switched to two tabs in the rear IIRC.

What kind of petcock opening does it have - round or oblong? What is the bolt spacing for the petcock mounts? The '78 should be 50mm I think.

[tweekin2]

M6-1.00 it is!

Once you confirmed the size, I hit up ACE again and bought a thread tap.
Hit it with some liquid wrench, and went right in. I think there was rust or something going on, but the tap when right in.
I am going to include some pics of the tank, as I probably need to know it in the long run.

[tweekin2]

Back mounting

Back mounting

[tweekin2]

Side view

Side view - I believe it is a Suzuki tank, as I have seen the two "holes" by the filler cap on others listed on Ebay.

[Dreef1999]

Looks a lot like an early gs550, gs550e tank. As i understand it the 550 tank is shorter than the 750 so it won't match up with your rear mounting point.

Why not buy the correct fitting tank??