Sunbeam S7 Deluxe - Crankcase Breather

I recently met up with a nearby Sunbeam owner from Lancaster County (across the river).  We compared our machines and discussed improvements and modifications.

One thing that my friend noticed was the crankcase breather on my Deluxe.  I wanted to avoid fouling plugs, and a disturbed mixture, so instead of routing the breather back into the air cleaner, I used a road tube.  Since there isn't much opportunity for a "draft tube" like on a car, another method was in order.  The standard breather "check" valves stopped working of course.

I obtained a brake booster check valve from Dorman products and mounted it alongside the frame rail, just above the side engine damper.  Since the valve's inlet port diameter was quite large, it needed to be reduced.  So I put another hose inside that one.  The outlet tube then goes along the frame rail behind the silencer.

The larger port is the inlet, the smaller one on the side is the outlet.

Part #: 80189

The brake booster check valve insures that crankcase is well vented.  The front of the engine stays clean, and the vapors are deposited well behind the rear wheel.

Valve Adjustment

KYL95 was getting a little clattery in the valve area.  I hadn't adjusted the valves since I put it back together, so I figured it was time.

They didn't seem to be too far off.

Petrol Taps

After consulting with the gurus at the ClassicGlory mailing list to confirm the Enots and Ewart type petcocks were rebuildable; I dove right in and stripped them down.  Unfortunately KYL95 has a mismatched set of petrol taps.  Left side is the original Enots type and the right side has a Ewarts valve.

The Enots type came apart easily and it was obvious that the cork seals were the original ones.  There was still a good bit left of them.  Still I'm impressed with the resilience of natural materials such as cork.  I decided to use real cork to replace them since I didn't have any neoprene handy.  The challenge is cutting the wine cork the right thickness, and making the cut parallel.  I managed a couple attempts with limited success until I got the feel for it.  Lengthwise with the grain obviously works better, and some gentle sanding gets it to the correct thickness.  I did a pressurized water test before reassembly and it works fine.  The slider is a bit scarred up, but its still pretty smooth.

The Ewarts type was a bit more challenging.  The rounded cork shape was not something I was prepared to replicate at the moment.  That would mean drilling out the centerpunch and then re-creating the whole brass inside part.  So I cheated.  I clipped the bad edge part of the cork plunger with a razor blade, and fitted a viton o-ring around it so that the o-ring would seal the plunger to the outside and stop it from leaking outside.  It doesn't seal 100% in the closed position, but as long as it doesn't leak down the side of the bike anymore.  I think I'll have to make a more permanent solution here... like maybe the correct Enots valve.

I didn't take photos of the fuel filters taken out of the tank.  I should have since they were a sight.  The right side was nearly blocked with varnish and junk.  The left side had some varnish on in, but wasn't nearly as bad.  A little carb cleaner and some gentle brushing cleaned them up nicely.