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by malcolm.johnson
Thu Aug 15, 2019 11:39 am
Forum: Four stroke
Topic: Valve stem oil seals
Replies: 7
Views: 196

Re: Valve stem oil seals

Valve springs - fitting.JPG Valve guides fitted.JPG When I rebuilt my 1947 iron 4G in 2012 I made my own guides and machined them to suit seals as pictured (early Land Rover I think). I only fitted them to the inlets. I do not ride the bike much but they have covered several hundred miles and it do...
by malcolm.johnson
Thu Aug 08, 2019 8:41 pm
Forum: Four stroke
Topic: spanner or socket
Replies: 10
Views: 565

Re: spanner or socket

Here is mine. I needed a spanner in a hurry so used some 1/4 plate I had. Centre punch, dividers, drills and a file. A good hours work and only ever used it once!
by malcolm.johnson
Thu Jun 13, 2019 9:38 pm
Forum: Four stroke
Topic: Aftermarket alloy singles barrel and piston.
Replies: 14
Views: 836

Re: Aftermarket alloy singles barrel and piston.

I understand that no head gasket is used with the alloy head and barrel set up and are just lapped in together save the pushrod tube seals. What torque setting should I use for the 4 waisted studs/nuts for this aftermarket barrel and alloy NH head?
by malcolm.johnson
Wed Jun 12, 2019 11:26 am
Forum: Four stroke
Topic: Aftermarket alloy singles barrel and piston.
Replies: 14
Views: 836

Re: Aftermarket alloy singles barrel and piston.

Thanks Simon, very useful info. It seems from that information, that the proper alloy head and barrel uses 5 studs/nuts, whereas my aftermarket barrel must be solely intended for use with the alloy NH head, which as you know, uses 4 bolts. At least I now know how to proceed with the top end. Thanks ...
by malcolm.johnson
Fri Jun 07, 2019 12:29 am
Forum: Four stroke
Topic: Aftermarket alloy singles barrel and piston.
Replies: 14
Views: 836

Re: Aftermarket alloy singles barrel and piston.

Simon, I have found that using a conventional length stud would not allow the removal of the cylinder head with the engine in the frame. I am sure if my measurements are correct, l will need a shorter stud and sleeve nuts, to enable the head to be lifted clear without fouling the inlet valve cap on ...
by malcolm.johnson
Wed Jun 05, 2019 5:47 pm
Forum: Four stroke
Topic: Aftermarket alloy singles barrel and piston.
Replies: 14
Views: 836

Re: Aftermarket alloy singles barrel and piston.

Thanks for the picture Simon. I could make some similar studs long enough to take a standard steel nut and also machine some sturdy washers to go under to spread the load? I meant to add that the only ID on the piston, is stamped small on the crown, is 434C7V. There are no cast in marks on the insid...
by malcolm.johnson
Wed Jun 05, 2019 11:47 am
Forum: Four stroke
Topic: Aftermarket alloy singles barrel and piston.
Replies: 14
Views: 836

Re: Aftermarket alloy singles barrel and piston.

Thankyou for the replies. I am building this bike as a "green laner" or long distance trials, so I anticipate longer runs. The oil pump I have is 1/4 inch dia for delivery side and 3/8 inch for scavenge, so hope this will do for starters. The alloy head has 3/8 inch holes right through. Fo...
by malcolm.johnson
Tue Jun 04, 2019 8:50 pm
Forum: Four stroke
Topic: Aftermarket alloy singles barrel and piston.
Replies: 14
Views: 836

Aftermarket alloy singles barrel and piston.

The pictures show an unused alloy barrel and piston that came with a quantity of singles parts from a deceased enthusiasts collection. He was I believe building a trials/green lane 350 using an aftermarket frame and NH engine. I raised a post about this frame several months ago and I have progressed...
by malcolm.johnson
Tue Jun 04, 2019 8:05 pm
Forum: Four stroke
Topic: Oil laek from dynamo gasket
Replies: 7
Views: 496

Re: Oil laek from dynamo gasket

I do not know about Huntmaster engines, but the BSA pre unit twins use a cork washer which is slightly compressed under the dynamo drive sprocket for the dynamo chain, to seal the only source of oil. Very similar engines. None of any of my BSA twins ever had that chamber fill with oil.
by malcolm.johnson
Thu May 23, 2019 12:16 pm
Forum: Forum Help
Topic: Topic symbols
Replies: 1
Views: 453

Topic symbols

On the left hand side of most topics there is a circle with horizontal lines, occasionally moving, sometimes red, sometimes blue and my last post unusually has a small red star. What does all this mean?

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