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B front head machining

Oldhaven

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VOC Member
Just as an interesting anecdote about early Vincent production, check the machining of this valve pocket on my B front head. It is off center and one edge is so thin that a small crack has formed. I treated it with wicking Loctite after noticing it in the final stages of assembly.

Ron
image.jpg
 

Albervin

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VOC Member
Fitting the cover must be interesting. Another observation, I assume you have 2 piece barrel/head bolts. There should be more thread sticking through the nuts unless you are using full width nuts. My bolts just sit proud of my lock nuts. Also, is there a washer missing from the RHS head bolt? Your bike appears to be about 28 after mine so I guess they were made in the same week.
 

Oldhaven

Well Known and Active Forum Website User
VOC Member
Fitting the cover must be interesting. Another observation, I assume you have 2 piece barrel/head bolts. There should be more thread sticking through the nuts unless you are using full width nuts. My bolts just sit proud of my lock nuts. Also, is there a washer missing from the RHS head bolt? Your bike appears to be about 28 after mine so I guess they were made in the same week.

The cap overhangs the mounting face a bit, yes. I expect sealing will be a bit chancy, but I have the Videan cap rings, so I hope that helps.
I noticed the inner bolts seem a bit far into the crankcases as I put on the head brackets, but didn't want to disturb them. That is where they were after the rebuilder finished up. He had to remove the inserts deep in the crankcases to clean out some bead blasting debris that I noticed as I (re)started the project two years ago. (It wasn't me..) At that point I decided to get some expert help, and I am glad I did.
The rear bolts are all flush with the lock nuts. I have the original 2 piece bolt head nut parts, and these SS replacements have the same dimensions. I can't see anything it affects since the spigot nuts have full thread engagement, and I am not using the oil galleries to the cylinders. I will have to find a different way to mount a hydraulic steering damper though, since there is no room for a bottom end bracket under the lock nuts. There is a washer there under all the nuts, matched for thickness, just not a good picture. The spring and seat is also centered in the pocket, but the angle of the camera makes it seem offset.

The engine left for Canada in the last days of October 1948. I think it was completed around the same day I was born in 1948, so it is my twin, in that sense. My UFM was shipped to the same small Canadian dealer in July of 1948 and somehow ended up with its brother engine . It is things like this machined pocket on this is 65 year old machine that amazes me that they are still running at all, let alone happily and frequently and with no significant disadvantages when even slightly modified for modern traffic. When I left the Navy and came to Maine, I worked at a small company that made winches and net reels for the fishing industry. I learned to be a machinist on old equipment that was pre-war and worn out even in 1978. I found out the meaning of fettling and selective fitting during those years. In these days I deal with multi axis CNC, CAD, CAM and 3D printing, and I really am in awe that the people at Stevenage could take a sheet of paper and design and produce something like the Series B so quickly and really successfully after WW II. I guess I can understand a few machining glitches on the machine.

Ron
 

Oldhaven

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VOC Member
Out of curiousity, Which small Canadian dealer, in what city in Canada was it shipped to?
Bob,

The dealer was Grant Budd of Prairie Motorcycles in Regina Saskatchewan. He brought in a total of 8 Rapides. 6 B's in 1948, and 2 C's in 1949. If I ever get my act together, probably after I get mine running, (yeah, I know...), I will write an article for MPH, since I spoke to him before he died.

Ron
 

Howard

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VOC Member
Another observation, I assume you have 2 piece barrel/head bolts. There should be more thread sticking through the nuts unless you are using full width nuts. My bolts just sit proud of my lock nuts.

Interesting point here, no one ever seems to do it (and Vins weren't assembled this way), but locknuts should be fitted below the full nut, otherwise the load is being taken by the thin nut.

H
 
Last edited by a moderator:

Oldhaven

Well Known and Active Forum Website User
VOC Member
Vibrac and Rip Tragle have posted pix of alternate damper mountings here on the Forum.

After considering the alternatives I backed the two inner bolts I would need for a damper plate up about 3/16"so they now have enough thread to install a thin bracket for a damper. I checked first and there was almost an inch of thread engagement with the ET158 inserts in the cases. The rebuilder had bottomed out the inners in the ET158's, but I would guess there is no need for this, and they were not in with any amount of torque and came up easily. I have not found anything in the reference books about how to tighten these inner bolts, though there is a lot about the outer hollow bolts used for the heads.

"Interesting point here, no one ever seems to do it (and Vins weren't assembled this way), but locknuts should be fitted below the full nut, otherwise the load is being taken by the thin nut.

H"

Howard, I don't understand what you mean. Is this with the one piece bolts? For two piece bolts there is only one lock nut and a spigot nut through the head brackets into the head bolts.

Ron
 
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