I’m a bit ebarrased to have to ask this as I expected fitting the exhausts to be straightforward…
I have a set of Keihan exhausts, plus the flange/clamp that fits to the cylinder head over the studs, plus two spacers per side, and a gasket per side. When I fit it all together, the exhaust can still move back and forth, rather than being clamped rigidly against the exhaust port - this feels wrong - can anyone advise please?
Also, on one side only, the nuts for the exhaust manifold studs bottom out, so nothing is tight at all on that side. I’m guessing I am fitting the spacers incorrectly, but there only seems to be one way of installing them, which is between the flange/clamp and the exhaust, with the collar towards the rear to prevent the exhaust being able to come out of the clamp.
Any diagrams/ advise would be very gratefully recieved.
The only thing that you may have done wrong is that you have put the two spaces in wrong,
the flanged part of the spacers should be pushed towards the exhaust port with the clamp, so the flanged part is away from the exhaust port, hope this makes it cleartying to make it clear.
Firstly insert the gaskets into the head. Check to make sure there aren’t any old ones left in there, they can get pretty squashed in.
Offer up the exhaust pipe and slide the spacers up the pipe with the small flange facing away from the head, then slide the large finned collar up. This should have a recess that fits the flange of the collar fits in. Hold the spacers in place whilst sliding the collar over the studs and tighten up the nuts. Everything should then go tight. The spacers should push against the flange on the end of the pipe.
My exhaust collets were in a not very good condition when I came to fit my headers on my V50 so I got some machined from aluminium taking the measurement from the clamp, exhaust diameter and outer gasket diameter, then hack sawed in half. When fitting its easier to hold the two collets in place with a bit of thin wire or what ever you have.
The only other item that I can think of is if you have not got usable copper seal rings. They compress over time, so new ones may be the order of the day.
It just occurred to me that Aluminium might not be the best choice for the collets due to the differential of coefficients of expansion. Aluminium is around twice the coefficient of steel. Being soft it will deform initially, but after a number of heat cycles will cause slackening of the joint. The collets are hidden inside the clamps, so should not be too unsightly. Any plating soon disintegrates at exhaust temperatures.
Just one question to make sure. You put two of them round the downpipe, say, holding them in place by zip-tie(they surprisingly do not melt). And wider end towards collet, yeah? As there’s a machined space in collet to hold them tight round the pipe. This is the way and you do it like that, am I right?
You are probably correct but it was the case of aluminium collets or no collets at all, so far your worries have not materialised no deforming and no slackening of the joint, not to say it will not happen but after a few hundred miles all looks fine.
Your description sounds the correct way to fit. Looking back I think I used a thin zip-tie to hold in place and I think I then put it off with a small blade when fitted, or wait till it melts.
