SU mystery component

[Paul P.]

HD began fitting wide flat rubber bands on the manifolds in 1978, though the '55 O-ring lips were still there on the heads and manifold. The bands allowed the manifold to creep away from the heads*, especially if it wasn't well braced (remember the "bread bin" air cleaner and its twin rocker box brackets) so in 1980 the manifold clamps were slotted in an attempt to put the pressure where it was best for securing. Somewhere around 1980 the manifolds/heads were now flat faced and no longer able to retro to the O-rings, which was a pity because they were better and they allowed the clamps to grip metal. I remember someone at Shipley who had loads of cracks in his flat band, affecting his running and I put the bands in boiling water and very carefully turned them inside out which at least got him home ok. The first photo in post 19 shows both types.

(* on the ferry going to a french Super Rally "Rowdy" and I were on his FLH with mates on a SuperGlide. Also aboard were a bunch of Gold Wingers and when we docked they were taking their bikes off one at a time with the rider paddling and a mate each side. Rowdy and I felt quite smug as we just blasted through them...until his carb fell off! We pulled up and elaborately "consulted" his map until they'd gone so we could squeeze it back on and wrap a bungee around it for the rest of the trip.)

[El Hombre]

I went through the saga of intake leaks and the solution for me was to make a pressure tester. I used it along with my airbrush compressor. You can use a normal compressor with a finely adjustable valve. The idea is to use soapy water around the seals to detect leaks. They bubble when there is a leak and it's very clear. The main benefit is you can set it all up and get the torque on the clamps right before putting the carb on. Saves a lot of faffing about in the long run. The support clamp can pull it out of line if it's not fitted properly, so it's very important to get that right. If you need to chat about it, send me a pm.

[Paul P.]

Good moment to share some wisdom - not mine, I got it from the founder of the now defunct Riders Club Italy (based on us!) who had his own HD workshop in Milan, a gifted mechanic driven away from Harleys by the tactics of the importer. Anyway, he liked to remove the manifold from the carb and fit it first so he could feel inside to ensure the O-ring hadn't been pinched or dislodged and that the faces were true. He also liked to offer up the manifold to the heads before he tightened them down to align the faces of the O-ring rebates because there was just enough play on the head bolts to improve the manifold seating. Though that might sound a bit anal I did work in his shop once for a couple of days (doing simple tasks I should add) and he demonstrated with a motor he was building how much difference it could make.

[robbiemac]

Andrew, i think this stuff may be just what you are looking for.....

https://www.amazon.co.uk/Heat-Mate-S...s%2C174&sr=8-5

[jayzedkay]

forget using using any goop, glue, silicon, whatever, you'll be forever chasing leaks.
The things i've found with using bands for quite some time now, with no leaks is care, attention
plus uber-carb support, not some twangy piece of flat-bar bolted to the case either, not on that brick of a carb anyway.

1. yes, forget any plastic B.S. machine some ally rings to press on that su o-ring maifold to make it a band-type.
better still offer it up and machine so they make the manifold fit perfectly between the inlet-bosses?

2. forget those third-party manifold bands, whoever made them, cometic, james, schmames. they're all crap.
To go all out, get some aircraft refuelling hose, 2" ID. It's not so easy to find, not at small lengths either.
second best, is what i use, and have done for years now. silicon reinforced hose.
I bought a small coupling off ebay for a few quid and made a couple of sets of bands.
one good aspect, is that you can make them a little wider, to take up the whole space.
Attachment 36060


Attachment 36062

get descent hose clips, again i got some off ebay.
stainless ones with a decent overlapp. which brings on the next bit.
i found that with bands less is more, if you bollock them up tight, that will leak, guarantee!
i found that as the clamp tightens around the band it grips and pinches, distorts and it leaks.
i used a flap-wheel in a drill and 'feathered' the internal-strap that constricts the band to clamp it.
see picture below with the feathered strap. not too much, you don't want a razor edge?



it'll pay dividends to make a leak tester.
i made mine with a piece of delrin, a guage i had kicking about and a schrader valve off ebay.
clamp it up with a smear of grease, use a hand pump to get a few psi, you don't need much.
if you can't hear a leak, soap test to find the tricky ones.
leave it a while pumped up to see if it loses pressure.
off course your's will need to match the SU flange.



finally the support.
i have a SU in my stash, that i intend to try at some point.
i will use the same support setup i use for my present CV.
but of course it'll have to match the su front flange again.
it's one of those aftermarket ones intended for a CV, but for an evo engine, i think?

You'll have to make it no one sells one for a su. flat-plate, card template, cut out, drill, bend it's made!
the carb support is kinda hung off small brackets bolted to under the rocker-covers.
i don't have any pictures of my current setup, and i'm away with work, so can't take any for a while.
This is a picture of the bracket i use, imagine it sandwiched, bolted between the air-cleaner backing-plate and carb.
then supported by the 'ears' either side by further small brackets bolted to the under-side of the rockers between the pushrods.




here's my attempt to draw one, to try and give an idea of how it goes?



good luck with the SU, be interested to hear how you get on with it.
J.

[Paul P.]

That grading of the leading edge on the clamp looks very logical! By the way, pre-breadbin aircleaner bikes (ie; pre 1978) are unlikely to have the threaded bosses on the under shelf of the rocker box.

[Hector H Taylor]

Thanks JZK, that’s a great help.
In the end, whilst I was searching for a suitable adhesive I found this epoxy:

It intrigued me and as the temperature in my garage is -20 I cooked up a plan that allowed me to work on the dining table.

I used 90 shore silicone putty to record the step in the flange and poured an artificial stone model into the mould, 2 off.(All this stuff is very accurate and stable.)
I then coated the stone with a separator and used the pukka bands to form an outside wall. I then found a flat faced disk to push down into the band to mould the top of, what would become, the ring of aluminium epoxy.


I mixed the epoxy as prescribed and carefully applied it to the stone, taking care to avoid trapping air, I then placed a disk of thin clear plastic over the epoxy and gently pushed down on the white disk. 2 off here too. 24 hours later I disassembled the mould and here’s what I had:


a piece of plate glass and 1000 grade paper removed the bits of flash, I then sand blasted the flange lightly (50 micron AlOx @ 2bar) and bonded the rings in place with the same epoxy. A further 24 hours and a bit of refinement with 1000 paper produced this:
(I seem to have reached the post limit, second post to follow ASAP)

[Hector H Taylor]

I bevelled the leading edge a bit as on original manifold and fitted it without any sign of distress, it’s tough stuff - especially in compression so I’m not expecting issues. It can be broken, I hit it with a hammer. It can be de-laminated from a flexible substrate but for my use it’s perfect and not as much of a faff as my explanation may make it seem.
I didn’t even mark it whilst clamping the manifold for drilling and tapping the support stud. (Warning above heeded - I will do something along those lines too.)

Thanks to everyone for their help and advice.

Cheers
Andrew

[Hector H Taylor]

“good luck with the SU, be interested to hear how you get on with it.”

I’ll let you know JZK.
In the meantime, are they ‘your’ rocker covers? I have seen crazy prices for new ones like that from the USA but I know standard ones can be split by someone who knows what they are doing. Do you have a contact or can help in any way? I’d like to explore any possibilities...

[jayzedkay]

H, yeah, my covers.
I did them myself, i came a cross a thread on a forum where the guy went through the steps,
but it was several years ago now and i have no idea where it was?

i did them by hand, pretty easy: pillar-drill, bandsaw, file and then emery/wet-dry to the level you want to go.
you cold do it with a hand-drill and hacksaw easy enough, i just had them at work at the time, thats all.
you can't really f**k it up, hardest part is starting, as there's no going back?

of course it'd be much easier to bolt them down and mill it out.

you have to have the oil-galleries you open up welded closed and dressed.
i have seen them done where you keep the oil-gallery intact, they just don't look as 'split'.
also some folks split them completely, as in they completely get rid of the area in the middle.
it appears not to prove problematic, i know of guys running some serious valve spring pressure without flex/movement etc.
i left the bit in the middle to have somehitng for the carb/air filter support, those underbolts work brill for the job.
plus it does still give them significant support in that area without really compromising the look.

if you keep shovel oiling, you have options to feed the rockers from the outside; via end-caps or retain some entry via the rocker cover itself.
you must have seen the various elaborate oil-tubing folks come upi with?
i have evo oiling (up through the pushrods) into evo-rockers, so done away with the oil-lines and keeps things clean and simple.

if it's soemhting you want to do, i can show you the general idea with photos on some spare rockers i have.
like show you where to drill and cut. pictures are so much easier than trying to describe the process.
but it'll have to be early march, i'm away with work and don't get home until and of feb.
give us a prob around that time if you want to pursue it.
where are you based?
j.