Radiator pipes

[klektermaniac]

Hello All,
1972 GT750J.
I am struggling to find any illustration for the radiator overflow pipes, and mine did not have them when I acquired it.
I am assuming that a small hose goes from the overflow outlet pipe on the radiator to the banjo on the metal filler neck. What is the purpose of this pipe?
Also one again assuming the overflow pipe proper goes from the top of the filler neck just under the filler cap. How long should this be and what is the routing, clips, etc?
A simple item but none of the illustrations I can find show the details.
Roger H.

[mizzytheman]

You’re lucky I’m in the process of renewing all the radiator hoses on the bike so just happen to have the radiator and hoses off whilst I’m waiting for the new ones to arrive. Obviously the small hose on the radiator attaches to the bottom connection on the expansion tank

The tank acts in two ways. First it acts as an overflow tank. You’ll notice in the top connection of the radiator there is a tang. If you fill past that level any water will overflow into the tank. Secondly it acts as an expansion tank. When the bike gets hot the water will expand and flow into the tank. When the water cools down, it contracts and water is drawn back into the radiator.

Top hose =50mm
Bottom hose= 55mm

Hope this helps.

[klektermaniac]

Hi,
My Kettle is a "J" and does not have an expansion tank like yours.
Also you state the hoses are 50mm and 55mm, but in the parts list they are the same part number and so the same size.
Thanks
RogerH.

[PaulD738]

Hi,
My Kettle is a "J" and does not have an expansion tank like yours.
Also you state the hoses are 50mm and 55mm, but in the parts list they are the same part number and so the same size.
Thanks
RogerH.

My 72J had one very similar to martins?

[mizzytheman]

Hi,
My Kettle is a "J" and does not have an expansion tank like yours.
Also you state the hoses are 50mm and 55mm, but in the parts list they are the same part number and so the same size.
Thanks
RogerH.

This diagram is from the 1972 service manual. Not sure what you have fitted to your bike but they are all similar across the range. Suzuki don’t supply two hoses they supply one hose with four clips. You then cut the hose to the required length.

[klektermaniac]

Hello,
Well mine does NOT have the header/overflow tank and I can now see the logic of having this for expansion. My bike was bought as a non runner but complete-ish, but obviously not with this tank. No wonder I am confused - thought this expansion tank was only fitted to later models!

How big is this header tank size wise? Is it just secured with the strap band with loops, and where exactly does it fit? Looks like there are a couple on ebay so they are out there, and the connecting hoses will be easy enough to find.

Thanks, I am a bit wiser now.
RogerH.

[klektermaniac]

This is what my radiator looked like.
The small hose from the top of the radiator was connected directly to the rad filler tube - you can see the union on the end of the pipe. This is why I was asking what purpose it served! No sub tank fitted.
RogerH.

[mizzytheman]

The sub tank fits On the frame as per my previous photo and held in place by a rubber strap. I’ll post some more photos tomorrow.

[mizzytheman]

Please see attached photos. Hope this helps.

[PaulD738]

Yup that’s exactly the same as was fitted to my J