Exhaust clamps
- Thread starter Stillreel
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I'm not full expert on all the variations of faults in Exhaust to head mis-fits but my first impression is the ring-bolts are hanging up in thread before seating the header. Its also frowned on be many, me included, to use any crush washers as the continue to crush down over time, heat vibration, to loose thread grip clamp force and beat snot out of the threads. Header should seat against deep port inner lip and ring-bolt seats on header flange, nothing else needed but anti-seize, like Milk of Magnesia, for as tight as they should be nipped up to stay put.
Headers come is many various constructions and errors so can't assume it ain't them w'/o close checking. I've had header the flange expanded section was too big OD but can't take much meat off the thin tube so ended up grinding most out my new brass rings to make work. ugh.
Make sure the ring-bolts can screw in all the way, if so then what's left to hang up but the pipes.
Headers come is many various constructions and errors so can't assume it ain't them w'/o close checking. I've had header the flange expanded section was too big OD but can't take much meat off the thin tube so ended up grinding most out my new brass rings to make work. ugh.
Make sure the ring-bolts can screw in all the way, if so then what's left to hang up but the pipes.
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Advice: Never use the stoopid tab- bend retaining washers as per stock. When your Ex. nuts decide to back off you don't know about inpending failure until the threads rattle-vibrate apart. Better to let the whole nut back out then you KNOW to pull over and tighten things. Some Ex. nuts have shorter threaded lengths and bottom out well before their time, leaving things loose. Anti -sieze to the threads good Hobot but Copper silicone even better. Use proper tool and reef those nuts down hot ,then do it again after a ride with all your strength. Honda CB 350 crush - rings good too. Hot critical.
Make sure the nuts thread smoothly all the way to the stops and till you run out of threads or bottom out. Do this without the pipe in place so you know you have a functioniing fastening system. Lube them with high temp anti sieze to protect the head threads.
As said, the jungle bells tab washers or just no good. Proper procedure is good.
As said, the jungle bells tab washers or just no good. Proper procedure is good.
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There is a guy on ebay who sells Stainless Steel exhaust nuts, they look great and fit better than regular Norton nuts. For my P-11 Scrambler I asked and he made me some aluminum nuts and they fit just as good but don't come loose. I plan to safety wire them but haven't yet. Maybe it's because the aluminum expansion matches the head expansion. I didn't tighten the aluminum nuts quite as tight as I have the steel nuts but they stay tight anyway.
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Well here's a first: in my search for slightly thicker crush gaskets, I pulled into a small garage on King East in Toronto. "Nice bike," says the mechanic, regarding the 68 TR6 that I drove in on. We talk a bit about the Norton and I show him the current gasket. He goes inside and returns with two Honda Civic gaskets that will work perfectly (approx 1/8 instead of 1/16"). "How much?" I ask. No charge, he says. Now that was a first for Toronto. Gotta love those vintage bikes.
Torontonian said:
I totally disagree with that. Fitted correctly the lock tabs prevent the nut from unwinding. 80,000kms and I have never had one go. Yes, tighten the nuts up really firm on a hot engine, preferrably running. Insert the tabs correctly and it is physically impossible for it to unwind.
Mick
My fastback needed two crush washers to make a tight connection. I found that I could cut down some of the old fork bushes that I had laying around and they fit perfect. They are a soft metal and seal just fine. The stock crush washers are not well made and there are lots of soft copper versions out there that work better anyway.
Mike
Mike
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Stillreel said:
I have a 750 and got some chromed nuts off e-bay.
I believe they are for an 850 and don't have the same depth as 750's.
Seemed ok with standard crush washers from OldBritts but noticed a rattley sound after a while when hot.
I could look down and see pipe shimmying.
When I installed I did the retighten after hot (80 ft/lb) and marked on nut and head with indelible marker so I could at a glance watch for loosening.
The marks indicated no loosening so mystery as to why when warm shaking pipe.
Figured nut had bottomed out short of full crush on washer, so I installed a second new crush washer on top of old crushed one.
Seems to be fine after about 2,000 miles so doubling up crush washer is my suggestion.
Bob
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With heat swelling and vibed crush washers crushing = clamp force can still dissolve w/o any turning to see. There is a reason crush washers, lock tabs and plain safety wire are not very popular among long time owners and cautioned against in updated tech manuals. If I was to use washers for too short a seating of ring-bolt I'd put them on face of ring-bolt not in front of header flange, which should seat fine directly on port lip.
Watch out for this variation for flange fitting.
Watch out for this variation for flange fitting.
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Well good going as that's the way it's supposed to work out - staying put with just pure brute torque. I've had exhaust 'nut' come off on hwy not pleasant sound or putting back off using road side trash to handle hot and stone to try to nip up to limp to real tools.
Awaiting the last shoe to drop on solving the current loose issue to file away for when its my turn again. On my special with Al 'nuts' I'll attempt spring attachments to slightly hold tightening pressure but may not need too with similar thermal expansion, but for sure can't brute torque like steel or brass ones need. Milk of Magnesia is famous hi temp anti-seize, but very thin so takes a few applications to dry on enough to help later.
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Stillreel said:
It just occurs to me that if you leave out the tab washer the nut will go further in and with standard crush washer may
hold pipe ok.
I remember reading somewhere that at the Norton factory they had a 4' pipe they used to assist the nut tightening so torquing the hell out of the nuts maybe all you need. The nut wrench I have allows me to put my torque wrench on it so 80ft-lbs works for me.
DogT
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rx7171 said:
Like this?
When mine loosened up the other day, I only had a small adjustable spanner and a screw driver to hammer the ring back tight. The engine was plenty hot after about an hour run and I notice it's still tight. I'm going to try ludwig's method of tightening it while the engine is running and maybe even punching it with a drift and hammer instead of the long extension. But you can really feel that ring tighten up with that extension, but don't over do it.
Dave
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When I bought my 1973 750. I noticed the muffler clamps were missing. I asked the seller about it. He said he doesn't use them, he claims it lets the head pipe move freely without stressing the whole system. First time I ever heard of this. The seller is a well known mechanic for british bikes. He's 77 years old and use to run the Bonneville Salt Flats... Anybody else ever heard of this?
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Gosh that's essentially what I've had to do by was too chicken to actually run w/o them but all the last years and this header removals did not require touching the loose clamps only for show around muffer end. So yes I can attest its perfectly fine practice and may likely be best practice. None the less the mufflers still get hot and bounce on the cushions so that part don't seem improved, just the header fractures and tedium to work useless clamps.
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DogT said:rx7171 said:
Like this?
When mine loosened up the other day, I only had a small adjustable spanner and a screw driver to hammer the ring back tight. The engine was plenty hot after about an hour run and I notice it's still tight. I'm going to try ludwig's method of tightening it while the engine is running and maybe even punching it with a drift and hammer instead of the long extension. But you can really feel that ring tighten up with that extension, but don't over do it.
Dave
69S
Yes that will give you serious torque but won't be able to measure it.
It looks like yours hooks onto one fin so not sure at what point may bend.
Mine grabs two fins so I'm pretty comfortable they won't bend.
Any beating on fins runs risk of damage.
My procedure is put anti seize on threads , tighten, ride ten minutes and tighten again with engine running about 3,000.
This works so well that in order to loosen the nuts I have to get engine hot and run again while lossening otherwise I can't get them to come.
Pretty good sign they are on for good.
The anti-seize may help because it bakes on when run and makes rattling loose less likely.
It does require me to take a wire brush to threads on nut and in exhaust ports before reinstalling.
Bob
DogT
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Can't measure it, but I sure can feel how the rings are going on. It also amplifies the feel of the threads engaging. I've got the Norvil type bronze rings so there are 3 double lugs on the thing and hooking the spanner on the double ones will not bend or damage anything. When I've used a drift and hammer, I also only use the double lugs to beat on.
The old ones were nearly impossible not to beat up because there was only one double lug. This is a result of a chain wrench.
Dave
69S
The old ones were nearly impossible not to beat up because there was only one double lug. This is a result of a chain wrench.
Dave
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I can't find the famous builders instruction on tightening but it involved 4 ft lever and body slams. I don't like to force anything so you know i grab a sledge hammer smack the fin wrench harder than regular impact. Lose nuts sink threads, merely good and snug ruins them in time.
Don't be wimps and double tap em a few times after the first seeming over doing by hammer or long lever. I prefer the shock tight method as over comes the extra friction of slo motion binding resistance. Wham Bam Thank you mam.
Don't be wimps and double tap em a few times after the first seeming over doing by hammer or long lever. I prefer the shock tight method as over comes the extra friction of slo motion binding resistance. Wham Bam Thank you mam.
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