[Karl Childers]

To start, I was putting the head on the  new barrel today and when I got to reinstalling the de-compressor it dawned on me the last person to work on the bike probably didn't put it back together right. It has one steel flat washer, one large flat copper washer at the top of the unit and that's it. When I looked at the washers in my de-coke washer set I had a large round copper washer and a small round copper washer which seems to make sense for sealing the lower portion of the unit. A closer look at the head showed a small port in the space between the top and bottom of the cavity which I am assuming  vents to the exhaust port. There was a discussion the other day about these washers but I wasn't quite grasping the whole thing. So do I now understand that small round copper washer goes on the bottom, then the large round one at the top backed by the flat steel washer.  If that's the case then what effect did only having a flat steel washer at the top with a flat copper washer and no washer at the bottom have ? I must have been losing some compression with that set up.

The other question also has to do with copper washers. The banjos for the oil feed to the rockers had no sealing washers when I removed them at the start of this project, I put this down to the last guy working on the motor didn't put them back, oil was seeping at those points. I expected to have four new copper washers in the de- coke kit but there were none making me question whether or not they were used at those joints. I did have some copper washers in my parts bin that fit so I sealed the joints with them. The question is did  these joints originally have washers or not? seems like they should have.

[ddavidv]

The answer to the second question (oil feed tubes) is yes, there should be copper washers there.

[Adrian II]

Of the two copper washers on the decomp valve, the M14 which sits at the top of the thread where the valve screws into the head is probably the most critical, though it's possible your valve managed a gas-tight seal without one. The upper one is intended to stop air leaks into the exhaust (which as you have correctly guessed is where the valve vents to) as well as exhaust gas leaks, not SO critical to the running of the engine, though air leaking into the exhaust on over-run might cause some unwelcome popping and banging in the exhaust. But then wasn't that what the emissions Pulse Air Valve was supposed to do?

A.

[Paul W]

My 350 (3,000 miles on the clock back then) came with aluminium crush washers on the oil feed banjos, rather than copper. So did the top end gasket set I bought when fixing the soft exhaust valve seat. They seem softer than the traditional copper type and I’ve been able to reuse them with any problem.

[Karl Childers]

Thank you all for the responses it helps me out. Sad thing is the last owner of the bike paid someone to do sloppy work like that. It will be good to get it put back together the right way.

[Paul W]

I think these bikes are probably better looked after on a DIY basis by a competent owner.

Once the owner understands them and has a basic tool kit they aren’t rocket science and need time more than anything which many garages aren’t inclined to put in.