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It was broken in two pieces, no longer just split.
Amal carbs and spark plugs issues and concerns
- Thread starter arcpoint
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Tornado
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Yes, it is supposed to be in two pieces....you place the two halves between the finned rose nuts and the pipe flanged ends, then the crush washer goes btwn flanged end and the head.
Have a close look at the correct parts diagram for your bike...can see them over on AndoverNorton website parts sections by model/year.
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The left one is one piece with a single slit/gap. The ones I just ordered look like the one I have that's not broken. Do you have to break them to get them on? I figured pull apart with some flex return. Now I'm really confused.
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No Andover Norton is like mine, one piece with a slit in one location. Part #
06.5260
EX. PIPE RETAINING COLLET
Tornado
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Found this older thread where the MK3 setup is described more:
1975 Mk3 exhaust downpipe fitting
Hi again everyone my exhaust front pipes are not the standard balanced pipes but are I believe earlier commando pipes unbalanced and fitted to pea shooters I had to remove my right side down pipe and when doing so 2 collets and a domed washer fell out and I did not see how or in which order or...
www.accessnorton.com
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Thanks, John. Turns out I had a broken collet and will follow your instructions to a T.I mentioned leaking header pipes as a very common source for backfiring in the third post on the thread. In fact in 50 years plus of playing with these bikes it's the issue 90 % of the time.
Your bike us a Mk 111. Which, should if it is original, have a different slightly different mounting system in the head. The same system is found on latter MK11 and Mk11 A models.
Originally it would have had a balance pipe between the headers. Many people take them off and install pipes without the balance tube but if you still have the balance pipe the joints are a very common place for leaks.
With a Mk 111 type fitting there are collets that secure the pipe into the head because the balance pipe joint does not allow the clamping ring to slide on from the other end of the header pipe.
If you do have the original collet system you should clean everything carefully and without the pipe installed screw in the clamping ring with the collets and measure where it ends up when fully screwed in. It should screw in by hand. No force required. Often you find the gap is wider than can be taken up by the header pipe flange and a single ring gasket. If it is you can try two gaskets or even longer collets if you can find them.
You will understand the explanation better if you just trial assemble the pieces.
When you get the space out right assemble with the pipes and use high temperature RTV to seal and hold the clamping ring in place. After your first few rides when the bike is still hot retighten the clamping ring. You may need to do this several times. There are proper spanners available to tighten them without butchering the clamp.
Last issue is that the threads into the head can be ruined by careless owners. If the threads are ruined they can be repaired. Your in the US so Ill leave to the local guys to suggest a suitable repair place.
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I get it now. This helps. I have the new seating washers and will go ahead and wait for the collets to arrive. I should've able to get a good seal, and with the cross pipe as well. Thanks! Will let you know how it goes.Found this older thread where the MK3 setup is described more:
There are no crush washers for MK3...just the slipt collet and a semipherical seating ring....no gaskets or crush washers used. The linked threads also mentions the collets are usually found to be fully split in to two halves....which is also how I found them on my '74 MK2 bike with the Y-type headers...though different than the MK3, using a crush washer and no semipherical seats. Perhaps AN sells them as single collet with a split and these need to be broken in two to fit over the pipe? Should not make any difference as they are only to engage with roses and press against the seating rings...should not matter if two halves or not.1975 Mk3 exhaust downpipe fitting
Hi again everyone my exhaust front pipes are not the standard balanced pipes but are I believe earlier commando pipes unbalanced and fitted to pea shooters I had to remove my right side down pipe and when doing so 2 collets and a domed washer fell out and I did not see how or in which order or...
johnm
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Hi.
I read the discussion about one piece and two piece collets. To be honest it probably hardly matters so long as you can get them to stay in place while you assemble the pieces. In my experience the critical thing is to ensure the stack of pieces are spaced out correctly. So that the clamping ring can indeed clamp tge pipe into the head without any movement in and out. I have never worried about adding an extra crush washer if needed. Just make sure the pipe is firmly clamped into the head. And use high temp rtv to stop it unwinding. Give it a few check tightening when warmed up and after a few rides. Its all dead easy and obvious once you look at it.
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Rich mixture makes plugs sooty. At what throttle opening are clean plugs becoming sooty in your engine?
Too-hot plugs cause pre-ignition and holed pistons.
What about the timing?
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There are two ways of getting jetting and timing right, presuming you are not changing anything else. You can set the timing to a fixed value and jet to suit it. Or it you have a dyno you can get the jetting correct using an oxygen probe and advance the timing until you get maximum torque. Either way you start with jets which flow to much and progress to smaller ones. You should use the next hottest heat range plugs for tuning. As you lean-off the jetting, the carbon will burn off further down the porcelain inside the plug. When you use recommended heat range plug, a block band about 2mm wide should remain on the porcelain right down inside the plug where it neets the metal. Your plugs should not be black, nor should they be totally white. The black band must be there. If the motor misses when you ride the bike, stop and raise the needles one notch - do not persevere.
