Triumph Header Clamps.

Hey Guys,

My neighbor has a '79 Triumph Bonneville (i know... i told him to buy a Norton). We rebuilt his carbs today and she was running great. After a short ride the left Header Exhaust Clamp worked it's way down the Header Pipe.

Obviously on a Norton, the header clamp screws in. I can't for the life of me figure out how the Header Clamp on a Triumph holds the Header in place?

Any explanation / tips will be appreciated.


thanks,

jsouthard said:

Obviously on a Norton, the header clamp screws in. I can't for the life of me figure out how the Header Clamp on a Triumph holds the Header in place?

Click to expand...

On Triumph twin "push-in" exhaust pipe heads, (used from mid-'72, to '80)* the finned exhaust rings are purely decorative items!

*(Not T140D)

Thanks LAB,

What holds the header in place if not the finned clamp?

jsouthard said:

Thanks LAB,

What holds the header in place if not the finned clamp?

Click to expand...

Magic but it doesn't last forever.

I would go as far as saying those Mk2 Amal,5 speed,disc brake Bonneville's might be the best all rounder of the lot as a every day bike.
The seat to tank (OIF) is a little odd but still a good looking bike.
With a unleaded conversion and modern electronic ignition reliable mileage would be a breeze,kick and go.

I'm a Triumph guy but not much after 1970. I do know that the push fit pipes were a problem and as mentioned that finned clamp is a style statement. There were three easy fixes:

1. Tap the exhaust outlet for the old style steel ex. stub but then you have to buy the old style push over pipes/clamps but done right it's pretty much permanent and most Brit Bike shops can handle the machine work if you don't want to own the tap.

2. Buy the alloy ex. stub inserts, heat the head and freeze the inserts and drive them in with a wood block and mallet, you then have to buy the old style push over pipes/clamps. As long as the originanl ex. outlet isn't hogged out this method works good because of the interference fit and both alloy head and stub expand together and stay tight...I prefer the steel stub in #1.

3. Buy the push in ex. sealing kit as seen in Classic Bike in the Shropshire Classic Motorcycles ad www.triumphbonneville.com and use the little jig plate and drill supplied to install, this way you can retain your stock push in pipes, it looks nice but negates the finned clamp with their collar. I have no experience with this kit but I believe an earlier CB mag had an article on the kits install. At least you get to keep your own pipes...

4. Not an option to me but have seen it done is to have alloy stubs welded into your ex. ports for use of early 1 3/4" push over pipes and clamps ...don't need this as an option except in maybe some extreme cases but I don't think you're there...option #1 is the best permanent fix if you don't mind buying pipes, hope this helps and if you need the tap size and want to do it yourself, John Healy has a good article in a past Tioc magazine outlining the procedure...Mark

I just reread your post and nowhere did it mention you were having ex. leak or loose pipe problems, so perhaps you just need to make sure the gap in the finned clamp is adequate so that when tightend down the clamp stays in place, my options were for loose or leaky exhausts although it is better to do a preemptive strike sometimes....Mark

http://www.billymegawatt.com/uploads/6/ ... racing.pdf

marksterrtt said:

I'm a Triumph guy but not much after 1970. I do know that the push fit pipes were a problem and as mentioned that finned clamp is a style statement. There were three easy fixes:

Click to expand...

Screw-in spigots can be troublesome,and cause a lot of damage if they work loose and bugger the threads.Best avoided,if possible.

I wouldn't use an aluminium spigot if my life depended on it.They're not strong enough.Triumph tried screw-aluminium spigots for a short time and quickly reverted.

I've turned steel spigots that are an interference fit in the head,and the same 1.65" diameter as the early spigots on the outside of the head.They don't generally come loose,but if it happened it would be no worse than the original push-in pipe.

Using exhaust spigots means using the earlier 650 pipes.The 650 was a taller engine (by about 3/8"),so the bottom run of the pipes will sit lower.

The original screwed in steel spigots, if done correctly, are the best fix in my opinion but aren't always done correctly. They have to be allowed to bottom on the step in the ex. port before the threads bottom out on the mouth of the port, other wise they will come loose and bugger up the threads. John Healy in the TIOC mag outlines the correct procedure for this often overlooked step in providing trouble free spigot install...not a big deal.

The alloy spigots were not a screwed in item but interference fit and although not ideal seemed to work for the most part.

If I were to machine steel interference fit spigots, I would go for a stainless alloy that expands close to that of the alloy head, perhaps 316 SS? I haven't had the need to do this, however I like the idea and will keep it in mind. Stainless steel threaded spigots are available and would be a good choice.

I can't comment on wether or not there are T140 speced header pipes with the T120 style expanded ends for the push over spigots, that would take a little research.

I think the bottom line here is that we are solving a problem that the original poster didn't report having, when I reread his post it described a loose faux clamp and nothing about an exhaust problem so....

Yes, the actual problem is a bad exhaust leak coming from the left header which also had a loose header clamp. Being a Norton owner I made the assumption that the finned clamp had something to do with the exhaust fitting tightly to the head. We also found a loose crossover tube and he is retightening up the entire exhaust system now.

Hopefully no additional modifications are needed, although I do appreciate the suggestions and options that are out there. Thanks guys, i'll let you know if we can get it sorted.

Joe, Triumph didn't stick with the push in ex. pipes for very long as they were troublesome....do a search for my option #3 as it uses the stock pipes but it's own collar secured to the head. It appears to be a decent kit and seals the leaks, installation also looks straight forward...Mark

jsouthard said:

Thanks LAB,

What holds the header in place if not the finned clamp?

Click to expand...

The bracket coming from the front engine stud attaches to a tab on the header. Pays to smear some exhaust jointing compound on the pipe end before inserting into the head. There are also after market finned rings that have a split with a screw so they grip like a sleeve clamp.

Joe, just a follow up, if you do decide to switch back to screw in exhaust stubs as Triumph did in 1980 then I can supply you with the machining info for tapping the head and also the late model T140 exhaust pipes part numbers that fit over the stubs, otherwise as others suggested, perhaps a hi-temp exhaust sealant on the offending exhaust will get you down the road..good luck, Mark