Misc: Everything Else 1951 Black Shadow Restoration

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
These thin nuts I tend to drill & tap 2BA in the corner of each hexagon, impact on nut drill recess hole into sprocket and loctite a grub screw in.
bananaman.
 

craig

Well Known and Active Forum User
VOC Member
Looking ahead at cyl/head assembly, i find i have 12 year old new in the package Maughan and VOC Spares push rod tubes and nuts.

The Maughan are machined tubes, square flange and twice the weight of the VOC Spares, 80gms vs 40gms.
Slightly smaller ID with Maughan as shown.

I am not sure which would fair better in service.
I do like the 6 slot Maughan tube nuts for the intake valves.
What does experience show?

20210503_PushrodTubeQ1.jpg
20210503_PushrodTubeNut1.jpg
 
Last edited:

greg brillus

Well Known and Active Forum User
VOC Member
Craig, I've had no experience with the solid machined Maughan's ones, but they look good......Just make sure the OD of the tubes is 0.75" in diameter. Check the fit of the tube into the head recess, the flanges can be a little snug and this causes grief when installing the tubes, seal washers and the flange nuts. If they are a bit snug just linish a bit off the OD of the flange........Good idea also to trial fit the flange nuts into the head, and wind them in a few threads to be sure everything is ok........A tight thread here can become disastrous if it goes in cross threaded......The new stainless ones have very sharp edges on the threads and can be easily crossed.........I prefer to use the original card type sealing washers one in the head and one between the underside of the flange and the flange nut........As per the fit of the tubes in the head........linish the OD of these lower sealing washers so they are a nice slide fit in the head, not tight, as this will also make assembly more difficult. Neal Videan's bonded seals seam like a good thing here, but the heat tends to melt the rubber, plus folk tend to over tighten the flange nuts, this crushes the seal into the thread in the head and makes future removal very difficult. Up to you but I use "O" rings in the crank case, 2 of per tube actually, and I always use a tiny smear of threebond around the small taper at the base of each pushrod tube........This mostly acts as a lubricant to assist the tube entering the case seal.......The tubes change in alignment with the case as the barrel/head is lowered into position.......Without this step, the tube can cut into the seal, pealing off a slither of rubber as it goes.
 

vibrac

Well Known and Active Forum User
VOC Member
With regard to the bottom tube seal I am beginning to think that the real culprit is not the pushrod tubes or the standard seals (and I have tried new tubes and all the options from O rings to special seals) or what glue you add to the assembly the fact that all my engines are oil tight there except one(and its not a 'D') is leading me to think the fault lies in the shape of the crankcase recess even given I cant see it. anyway as I said on another thread, sod it it can weep this season I am riding.
 

Robert Watson

Well Known and Active Forum User
VOC Member
When I built the 100 bike Rapide for my son it had a consistent oil leak from the main crankcase drain plug. I tried all kinds of gaskets before I got serious. turned out that the threads were not square to the bottom of the recess by a substantial amount. I ended up making a 1/4 bsf mandrel and recutting the recess with a small piloted fly cutter. No more leak. Back in the day (the cases had been apart since the sixties!) it must have driven someone crazy!
 

craig

Well Known and Active Forum User
VOC Member
I spent some time reacquainting myself with pushrod tubes ET46 and gland rings ET104.
The ET104 glands went in with some difficulty chasing them around the crankcase openings, adding some grease, then allowing them to fold inward and other techniques. Finally learning what to do, got em in.

Then I grabbed a new standard pushrod tube and I could not get it to go in any of the gland seals....grease, push pull, lots of pressure , almost grabbed a rubber hammer, but did not. How could this be? I have put many of these in and it was easy peasy slip in.
PushrodTubeInstall2.jpg
 

craig

Well Known and Active Forum User
VOC Member
I got out some old pushrod tubes and had a compare on the entry end of the tubes.

20210504_PushrodTubeEndCompare1.jpg



It was easy to grind and polish a bevel on the new standard pushrod tubes and it is easy peasy to install.
 

craig

Well Known and Active Forum User
VOC Member
I am fitting The G52 chain sealing felt ring to G51 chain sprocket cover. And then fitting the felt into G22.
Even oil soaked G22 became a brake drum jammed up with felt ring and cover.....all spinning together.

What is the tooling/process to reduce the G52 felt ring?


20210508_FeltG52Fitment.jpg


This picture shows the out of package G52 oiled up and trial installed causing lock up to the right. A slightly smaller G52 out of another pakage.
 

greg brillus

Well Known and Active Forum User
VOC Member
The modern felt seals seam to be quite weak.......Used in the brakes they tend to roll themselves up and break up.........Sometimes you can place a length of wooden dowel inside the seal and cut it with a sharp stanley knife or similar. On the G 52 I tend to re use the original if it is in good condition, wash it in petrol dry it out, lightly coat with grease and re install it. I don't use the modern replacements at all......In the brakes I use the thin Nilos seals that seem to work fine when set up correctly.
 

Bill Thomas

Well Known and Active Forum User
VOC Member
Have you bashed the tin plate into the resess, To stop it turning ?.
There is a half round resess at 7 o clock in the hole in G50,
You can see it in your first photo of your bits, And when the gearchange bits are fitted,
It should be stopped from turning .
 
Last edited:
Top