Exhaust Rose size

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Hi,

re: 1975 Norton MK3 with peashooter exhausts

Been away from this forum for a bit, using the Norton at least twice a week for 100-150 mile spins :mrgreen:

Overall the bike is running well, few little niggle leaks which I'll look at over the winter.

OK, exhaust roses. My LH header decided to split, I got replacements from Angie in Mick Hemmings, lovely lady, ordered them on Weds & got them today, Friday morning.

Just fitted the LH pipe for the moment & went for a 20 mile blast & tightened the exhaust rose. Bike is running great :D

I noticed with the old pipes the exhaust rose tightened right up to the head, with the new pipes the exhaust rose has about a 1/4" of thread still showing after it is fully tight.

I did not fit the old exhaust of the bike so I'm unsure what they are from (750/850 etc.)

Is it possible that the old pipes are from a 750 & required longer threaded exhaust roses? Anybody see a problem with using the longer exhaust rose?


When I took the old pipes off there was nothing in the head except a copper crush washer, I've seen discussions on this board about exhaust collates, I don't seem to have any, again is this 'normal'?
 
Collets used on pipes with a crossover only, sounds like NON crossover pipes were retrofitted.
 
concours said:
Collets used on pipes with a crossover only, sounds like NON crossover pipes were retrofitted.
Click to expand...

Correct, non-crossover, peashooter conversion was already done when I got the bike
 
concours said:
MKIII uses a spherical seat inserted into the head to match the MKIII only pipes. Stop, review the parts diagrams at http://www.oldbritts.com and regroup.
Click to expand...


Sounds like I'm OK since I don't have the original 850 MKIII crossover pipes.

I think what I have are the longer 750 exhaust roses + non-crossover 850 downtubes and no collets.
 
click said:
concours said:
MKIII uses a spherical seat inserted into the head to match the MKIII only pipes. Stop, review the parts diagrams at http://www.oldbritts.com and regroup.
Click to expand...


Sounds like I'm OK since I don't have the original 850 MKIII crossover pipes.

I think what I have are the longer 750 exhaust roses + non-crossover 850 downtubes and no collets.
Click to expand...
Maybe one side has the seat still in place, not the other, causing the difference?
 
concours said:
click said:
concours said:
MKIII uses a spherical seat inserted into the head to match the MKIII only pipes. Stop, review the parts diagrams at http://www.oldbritts.com and regroup.
Click to expand...


Sounds like I'm OK since I don't have the original 850 MKIII crossover pipes.

I think what I have are the longer 750 exhaust roses + non-crossover 850 downtubes and no collets.
Click to expand...
Maybe one side has the seat still in place, not the other, causing the difference?
Click to expand...

Just to clarify, I only replaced one side with a new downpipe, I wanted to get out for a spin ASAP :mrgreen:

The difference I'm referring to is in relation to the old & new downpipes, with the old the exhaust rose tightened up to the head with the new downpipe there's about a 1/4" of thread showing on the exhaust rose.

My understanding is that the 750 exhaust rose is longer than the STD 850 one, I'm presuming there is no issue using the longer exhaust rose with the 850 downpipes? At least you are certain it is fully snugged up!!!
 
click said:
Just to clarify, I only replaced one side with a new downpipe, I wanted to get out for a spin ASAP :mrgreen:

The difference I'm referring to is in relation to the old & new downpipes, with the old the exhaust rose tightened up to the head with the new downpipe there's about a 1/4" of thread showing on the exhaust rose.

My understanding is that the 750 exhaust rose is longer than the STD 850 one, I'm presuming there is no issue using the longer exhaust rose with the 850 downpipes? At least you are certain it is fully snugged up!!!
Click to expand...
Correct.

engineering-compromises-leading-exhaust-threads-stripped-t14363.html#p172161
 
Only thing the matters is the ring bolt is long enough reach to seat on the header flange jammed tight against lip of the exhaust port. If washer spacers used, must really stay ahead of the heated black smithing crushing down the washers till threads not under tension then engine vibes beat threads to dust. Header sure better seat all the way in and not hanging up preventing full ring bolt clamping. My bronze ones show some threads still exposed too on Victory headers that put too much meat in the flange This is a case where manual listed torque is not really enough. I will not use crushable washers anymore myself nor lock notch washer nor safety wire, just brute blunt force or springs.
 
concours said:
click said:
Just to clarify, I only replaced one side with a new downpipe, I wanted to get out for a spin ASAP :mrgreen:

The difference I'm referring to is in relation to the old & new downpipes, with the old the exhaust rose tightened up to the head with the new downpipe there's about a 1/4" of thread showing on the exhaust rose.

My understanding is that the 750 exhaust rose is longer than the STD 850 one, I'm presuming there is no issue using the longer exhaust rose with the 850 downpipes? At least you are certain it is fully snugged up!!!
Click to expand...
Correct.

engineering-compromises-leading-exhaust-threads-stripped-t14363.html#p172161
Click to expand...

Thanks for the link :D
 
hobot said:
Only thing the matters is the ring bolt is long enough reach to seat on the header flange jammed tight against lip of the exhaust port. If washer spacers used, must really stay ahead of the heated black smithing crushing down the washers till threads not under tension then engine vibes beat threads to dust. Header sure better seat all the way in and not hanging up preventing full ring bolt clamping. My bronze ones show some threads still exposed too on Victory headers that put too much meat in the flange This is a case where manual listed torque is not really enough. I will not use crushable washers anymore myself nor lock notch washer nor safety wire, just brute blunt force or springs.
Click to expand...


Hi Hotbot,

Thanks for the extra info.. I've got a large spanner for tightening the exhaust roses so I can apply plenty of brute blunt force :roll:
 
A hand turned spanner that can fit in a tool box is not enough on its own, it needs a few more feet of lever or a few lbs of sludge hammering. Crude hamfisted as this sounds its the sound advise of famous builders. Once i got over my timidness and got a decent tool made to grab the thick fin blocks its a do it once task for me. I've been very pleased dipping dabbling Milk of Magnesia as anti seize that acts like locktite till first slight turn then smooth sailing to unscrew. Tried it on lawn mower header bolts d/t hole in old muffler and they too held snug yet backed put w/o fight.
 
hobot said:
A hand turned spanner that can fit in a tool box is not enough on its own, it needs a few more feet of lever or a few lbs of sludge hammering. Crude hamfisted as this sounds its the sound advise of famous builders. Once i got over my timidness and got a decent tool made to grab the thick fin blocks its a do it once task for me. I've been very pleased dipping dabbling Milk of Magnesia as anti seize that acts like locktite till first slight turn then smooth sailing to unscrew. Tried it on lawn mower header bolts d/t hole in old muffler and they too held snug yet backed put w/o fight.
Click to expand...


Hi Hotbot,

I've read you & others mention the use of MoM as an anti-seize, I thought it was a bit 'kookey' but I've Googl'ed around & have found mention of it's use in some aerospace applications!!

Once again thanks for all the advice.
 
click said:
I've read you & others mention the use of MoM as an anti-seize, I thought it was a bit 'kookey' but I've Googl'ed around & have found mention of it's use in some aerospace applications!!
Click to expand...

Graphite paste (such as Graphogen) is another option and is what I use, as the 'grease' burns away-but the graphite doesn't.

Exhaust Rose size
 
Permatex high-temp silicone ULTRA COPPER. Smear it into the clean threads. Use tons of force ,stand on the extended tool and jump up and down. The other side I use a 5 lb. sledge to hit upwards. No retainers or safety wire , these only increase the chance of thread chatter should things start to back off. Better to know by exhaust blast noise ,then deal with it. Never had a back off with this simple way. Honda CB 350 crush rings are copper too.
 
Hehe, I love the double takes on my seemingly off the planet remarks and conclusions. The grey metal dust anti seize tends to melt out, the sillycone works as long as its layer stays trapped but is a bugger to pick out of threads to re do. I'm happy with the MOM since trying its on Norton and Kohler 18 hp twin. I've tried it by layering on till dry and just screwing together wet to find both ways do the job.

Exhaust Rose size
 
Well its use sure makes me feel like a despot beating down the population in the name of its own good. I've had em come loose on the fly and sounds like engine blowing up. I got the blue ring bolt grabber in a buy of a factory tool set and it came with a yellow handle on it but its a joke and just slips off as the real torque applied. I hit with same force as driving a hardened nail into cement. The seemingly extra smack force seems to send shock wave ripple that breaks friction to really seat well w/o any binding on thread resistance, especially with Milk of Magnesia wet or dry. So don't force and strain yourself on this just get a bigger hammer.
 
Hump Marx was basicaly a product of City of London Rothchilds so had a big part in the tough financial policy on some industry to avoid slip shod products. You do your own search on the clue that ain't very funny.

The brass or bronze 'roses' are my favorite now and have held up to my sickle and hammering.
 
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