Why You Need or Don’t Need Them
*Want to watch a quick video instead of reading the blog?
Scroll down to the bottom for our video on spigots!
When deciding which exhaust system is right for your bike it is important to know what head your motor has. Never assume that there is such a thing as stock when it comes to a British bike. Some 1970s heads have spigots while others do not; some spigots are threaded into the head, some are pressed. This is an easy error to correct by looking at your head and, by all means, remove your old headers to see exactly what you have and what you want.
This picture is a 1975 exhaust next to a 1975 exhaust clamp. As you can see even though the parts are both from the same year, these classic British spares are very different, that clamp will never go over that header. The clamp here goes to a T140 engine that has pipes that were just shoved into the head, expecting the balance tube to hold the headers in. The pipes in the picture are for the T140 that has spigots pressed into or threaded into it. Both parts for a 1975 T140, but drastically different.
So, what we have is a situation where your parts book tells you one thing, but reality tells another. Often people did not like the stab in pipes as they leaked gasses so bad backfiring resulted. So, they either pressed in or threaded in exhaust spigots to solve this problem. That also gave them the ability to use unbalanced pipes that were very popular in the 1970’s for their clean look.
When purchasing exhaust parts three things need to be taken into account.
- Does my head have spigots?
- Do I want my head to have spigots?
- What exhaust headers are available to me based on the last two questions?
These answers tell us what spigots, if any, what pipes and what exhaust clamps will work on your bike. So, use your measuring calipers and remember to take your old pipes apart and see what exactly you are dealing with before ordering any replacements or upgrades.
We also have oversize thread 70-3583/70-9516 if your old “stab in” head has its original threads messed up by loose fitting pipes rattling around (that happened a lot to T140s).
TAKE INVENTORY OF YOUR BIKE
– KNOW YOUR PIPES –
– KNOW YOUR SPIGOTS-
– KNOW YOUR CLAMPS –
If you still have questions you can email, call or text us! orders@thebonnevilleshop.com CALL: 720-570-7884 TEXT: 720-260-4271