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Cyborg #854839 07/28/21 5:10 pm
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Support your #1 Vincent Forum
Cyborg #854849 07/28/21 9:24 pm
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someone's underpants?


1972 Triumph T120
1968 BSA A65
1968 MGB Roadster
1979 Chevrolet Camaro Berlinetta
1969 Honda Mini Trail
2004 Honda Shadow Aero
1949 Ferguson TE20 tractor
1975 yamaha xs650b
1972 Norton commando
2 olive drab WWII military bicycle replicas
raf940 #854859 07/28/21 10:59 pm
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Originally Posted by raf940
someone's underpants?

Now that would put a damper on the marital bliss! I was entertaining the rug rats while making a switch plate. They are for switching ignition maps. Waterproof covers are yet to be installed.


[Linked Image from live.staticflickr.com]75831FF4-FFCC-4B68-9148-552264783F90 by First Last, on Flickr

Last edited by Cyborg; 07/29/21 2:43 am.
Cyborg #854862 07/28/21 11:32 pm
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It's quite obvious that they are Fembot gun ports from the Austin Powers spy movies.....shagadelic, baby!

Cyborg #863200 11/15/21 2:55 am
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The apprentice approves. Getting a little ahead of himself though.

[Linked Image from live.staticflickr.com]15E6B11B-541F-4B74-B0AB-FDFB1A0CED29 by First Last, on Flickr

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Cyborg #863347 11/16/21 9:27 pm
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That's the spirit, catch and hook 'em young - they 'get it'.

Cyborg #863394 11/17/21 4:38 pm
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There is hope for this one. He’s an absolute wild man…. and for his age has a really good understanding of how things work.
There is a Harley owner on the other branch of his family tree, so I feel compelled to make sure he becomes a little more cultured. He started the MG V11 a couple of weeks ago and his eyes were like dinner plates. Needed his dad!

That photo reminds me that I still need to add a breather to the tank or cap.

Last edited by Cyborg; 11/17/21 4:45 pm.
Cyborg #863495 11/19/21 3:49 am
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Set up some better lighting and blew the dust off.

[Linked Image from live.staticflickr.com]9709808F-2C74-46CC-95DD-3D08BEE7656A by First Last, on Flickr

Cyborg #863568 11/19/21 10:20 pm
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Now, now. You trying to shame me into action?.......Just got too much on at the moment.
I like the jig for the cluster.

Cyborg #863639 11/20/21 7:30 pm
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Original post 01/25, 2020
"Washing off 70 yrs of dust."

Yesterday
"Set up some better lighting and blew the dust off."


You're rounding third...


1970 T120R - 'Anton'
1970 Commando - 'Bruno'
1967 T120R - 'Caesar'
1968 Lightning - 'Dora'
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Originally Posted by Hugh Jörgen
Original post 01/25, 2020
"Washing off 70 yrs of dust."

Yesterday
"Set up some better lighting and blew the dust off."


You're rounding third...

No [***]! Although some of my posts might suggest I spend too much time contemplating my navel or just generally farting around, I have finished (or almost finished) a few projects. The Comet powered abortion in the photo above took about 2 years to complete, which unfortunately is about average.

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Originally Posted by Twin Pot Phil
Now, now. You trying to shame me into action?.......Just got too much on at the moment.
I like the jig for the cluster.

As Hugh so kindly pointed out, you shouldn’t feel shamed into anything. I have a relatively narrow window ( between construction/renovation projects) so unlikely much headway will be made in the short term.
I haven’t used the jig before, but due to the fact that these are NOS cases….the innards of the gearbox are a collection of NOS, used and new, and none of it ever “ belonged” together, the jig might be a good idea. I won’t know until I’m done. Thinking I will add the actual detent setup for the shift plate just for sport. One of your fellow countrymen offered to make the jig for me, but I told him I would be happy with just the drawings. There is another member who stops in here once in a blue moon who has a similar setup. He made his so the plate that holds the G34 (cam plate spindle) can be adjusted from side to side. My understanding is it’s for dealing with cases where the spindle boss has parted ways. When the boss is repaired and case mating faces are resurfaced due to warping etc the spindle isn’t necessarily in the stock location. I can only assume that the stock spindle location varies too. Sort of like my breather spindle that took a -10 half time pinion before it fit properly.

You are also off the hook because the crank hiding under that rag is ok, but…… Anyway, I was thinking of assembling a better crank. As in why put an “OK” crank in basically a new engine (not really happy with the drive side mainshaft mills pin situation on this one). I did the crank for the Comet and it turned out surprisingly well considering my level of experience and equipment available. For this engine, I acquired a NOS Alpha pin….. with an additional.250”of girth and a pair of really impressive nuts, but couldn’t come to terms with using the stock rods. The polished ones on the bench looked ok from a distance, but some rough measurements suggest that too much material was removed from the big end. As you know, they go egg shaped when the outer race is pressed in and then you pray it can be honed or lapped round again before you end up beyond the desired running clearance. So…. I got on the blower to order up a pair of Corrillo rods and that ended up in a serious bout of mission creep and toy fund depletion. It’ll likely be a while before it all finds its way to the bench.

Cyborg #863763 11/21/21 10:01 pm
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Originally Posted by Cyborg
I have a relatively narrow window ( between construction/renovation projects) so unlikely much headway will be made in the short term.
Same here, been on a huge renovation/construction project for the last lifetime (well it seems that long!!), desperate to get back into the workshop and back to motorcycles.

Originally Posted by Cyborg
As you know, they go egg shaped when the outer race is pressed in and then you pray it can be honed or lapped round again before you end up beyond the desired running clearance.
Well, when I built my outfit for historic road races I used a second hand pair of rods of unknown heritage, had them polished and shot peened (I didn't tell the polisher that I was going to ruin his beautifull finish) and new big end - big pin Alpha, fitted by the legend that is the late Bob Dunn, I know that any undesireable behaviour would have resulted in Bob rejecting them, was I just lucky with this pair? (doesn't usually happen to me!!). They have had some serious use and abuse since then, Bob even declared the crank assembly "perfect" when he checked it after 1000 racing miles.

Cyborg #863777 11/21/21 11:40 pm
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I’m certainly no expert on the subject and have only done a few cranks…. I actually believe there is an element of luck involved and sometimes lots of luck. I have several other rods that were in the pile that was given to me. No idea when they were actually manufactured, but there are subtle differences. The polished ones actually have more meat in some areas around the big end eye compared to other unpolished rods…. but less material in the rib that goes around the centre of the big end. I know stock rods and (old) Alpha bearing can be made to work because the Comet one came out round.

I grabbed one of the polished rods and zeroed a bore gauge width wise in the bigend. Turning the gauge 90 degrees gave me this….
[Linked Image from live.staticflickr.com]9B550A70-E3ED-44BE-B6BA-F13F4653536D by First Last, on Flickr

I left it zeroed in the same location and measured the other rod. It was .0034” wider, but only out of round by .0004”
The thing I have trouble dealing with is what route does one take? Some beat the hole round before the outer race is pressed in. Some hone the hole round first. Neither of those options really appeal to me. Plus… at the end of the day, as soon as you press in the new race, it will most likely go egg shaped again. Some use a completely different outer race with a smaller ID and then it is sized. That way it can be made round before it becomes too large (over service limit). The bigend bearing I have comes with the outer race fitted. No idea what the clearance is as it sits now, but there won’t be much material to play with. Maybe Bob used his own outer races? The Corrillo rods are stronger in that area and I’m guessing the vibrac ones were as well. At a later date I may have a go at using stock rods, but the route I took was the path of least resistance. Plus I need a better lap or a real hone. Not to mention big Bertha should get some TLC before I would try enlarging the pin holes.

PS. Just for fun I weighed some of the rods. The heavier of the two polished ones weighs in at 536 grams vs 508 for an unpolished rod, so maybe as time went on, they added more meat to the bottom of the rods?

Last edited by Cyborg; 11/22/21 4:34 pm.
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Cyborg #863871 11/22/21 9:20 pm
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Just for you Hugh……

The cylinder may still need some attention before it’s bolted down for the final time…. as in make sure the mating surfaces are where they should be. This is just a dry run for proof of concept. I used the lathe before because when a cylinder was bolted down to the mill table, it didn’t leave enough room to work. A different boring head/ cutter setup appears to have cured that. Bottom plate that anchors the 4 studs is bolted (in the centre) to the mill table and the clamps are just snug enough….. hopefully. The indicator tells me how much deflection there is when I grab the cylinder and reef on it.

[Linked Image from live.staticflickr.com]492C960E-9C63-4601-8C87-2F6BB490165D by First Last, on Flickr

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Cyborg #865259 12/04/21 10:26 pm
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Ken, there are loads of variations in rod dimensions, I have always presumed that as the forging dies wore/ refurbed/replaced the produced rod would change in one form or another. Vibrac rods do have slightly more metal in them compared to the standard road offering.
I cannot get to any of my rods (used and spare) to compare, the workshop seems to be getting further and further into the distance just lately!!!!

I think we frequently forget that we are dealing with very old pieces of metal that have inherently moved and changed form slightly since they were first machined over the interveening 70 odd years - most crankcase main bearing housings these days are actually oval and require sleeving back to a proper bearing fit.

With regard to cylinder muffs, there are numerous examples out there of them being produced with the bore not being perpendicular to the base and the bore not being the right size to the liner, and the liner being made undersize to the muff bore..........

Cyborg #865291 12/05/21 4:26 am
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I wonder if over the years the rods were made by different suppliers as well. The more I think about them, the easier it is for me to rationalize spending the money for the Carrillo rods….along with the other necessary attachments.
At least I don’t have to worry about bearing bores with the NOS cases. Some bores were actually undersize. The cases have worked out perfectly so far. As long as there are no surprises when the gear cluster gets loaded, life will be good.
My cylinder boring setup on the mill turned out to be shite. No power feed in the Z axis, plus I have to lower the quill and raise the knee to make a full pass. Awkward setup….Life is too short for that nonsense. Plan B…..

Cyborg #865320 12/05/21 2:30 pm
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Originally Posted by Cyborg
I wonder if over the years the rods were made by different suppliers as well.
Quite possibly as Vincents went bust many times an unpaid previous supplier would have to be avoided for future supply, otherwise, forging dies eventually wear past the point of refurb and have to be replaced, which is the obvious point of product change introduction.

Originally Posted by Cyborg
At least I don’t have to worry about bearing bores with the NOS cases.
Be careful and measure before installation, the late very great Bob Dunn told me that even (hypothetically) unused (who would ever dream that period NOS would ever turn up!!) cases would distort anyhow because there are different quantities of metal exerting greater and lesser degrees of inherent movement force around the same hole over a long elapsed time period - something a manufacturer would never have to consider.

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Originally Posted by Twin Pot Phil
Originally Posted by Cyborg
At least I don’t have to worry about bearing bores with the NOS cases.
Be careful and measure before installation, the late very great Bob Dunn told me that even (hypothetically) unused (who would ever dream that period NOS would ever turn up!!) cases would distort anyhow because there are different quantities of metal exerting greater and lesser degrees of inherent movement force around the same hole over a long elapsed time period - something a manufacturer would never have to consider.


ive always found that interesting. one comment i read many years ago was similar, in that a rebuilder explained that even a new old stock set of Vincent cases would have to be blueprinted before it could be assembled into a reliable motor-- not because of imprecision in manufacture, but because of this metal-creep over a long period of time.

perhaps it was the same individual?


i'm old enough to remember when patriotism meant not trying to overthrow the government.
Cyborg #865339 12/05/21 5:58 pm
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Wasn’t it Rolls who used to toss their engine blocks outside onto the heap and let them age? No doubt these cases have shifted around. Lots of the machining wasn’t done properly. There is even suspicion that Stevenage did some of the machining and then later on some was done by Harpers. One of the gearbox bores was tapered, but luckily the way it was done still left enough material to straighten it out to the correct size. Assuming these case have finished shifting around (until it’s thrashed), they should be as close to perfect as one can get original cases. The complete description would be rather lengthy, but a couple of highlights would be that the cylinder decks are parallel to the crank within .001” over 10 inches and the bearing bores are pretty much perfectly aligned. The roller bearing outer races (including the small one) were lapped to size after installation. No guessing if a C3 will give you the correct running clearance. Some disagree with that method, but lapping can give you extreme accuracy if done correctly. New spindles all around and bores are perfect. Only odd thing so far was it took a -10 to get the correct backlash between the small idler and the front cam. I say small idler because these are the later die cast cases and a D type breather is used. If I used smiley faces, I’d use one here….. the die cast have way more material supporting the (G34,G39AS), Shift plate spindle etc.

This kind of work is out of my wheelhouse, plus even doing the basics would have been a pain with my mill.

Photo of the cases in my mill.

[Linked Image from live.staticflickr.com]75BD0C03-306C-4398-8527-C4B0F8A8E8EB by First Last, on Flickr

Last edited by Cyborg; 12/05/21 6:03 pm.
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I think it was common practice for iron cylinder castings to be left outside to season, on many makes of bike.


Amateur Loctite enthusiast.
Cyborg #865373 12/05/21 9:43 pm
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I grew up in Rugby, UK
The two main employers, employing 12,000 and 10,000 people respectively were AEI and English Electric.
Both made steam turbine generators.
I think they are now part of Alsthom.
The main shafts of the turbines were made from castings about 30 feet long and 4 feet diameter.
After delivery and before machining they were left outside in the open air for at least two years to stress relieve.

As a side note while I lived there one of the shafts whilst being turned on a BIG lathe came away from the chuck.
The energy involved was so great that it went through the factory wall and ended up two fields away having killed two cows en route.

Oh the fun that was to be had before short sighted politicians adopted policies that saw everything move to China!

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Originally Posted by Tridentman
Oh the fun that was to be had before short sighted politicians adopted policies that saw everything move to China!
But think of how many cows were saved.

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Originally Posted by Tridentman
As a side note while I lived there one of the shafts whilst being turned on a BIG lathe came away from the chuck.
The energy involved was so great that it went through the factory wall and ended up two fields away having killed two cows en route.!

Sounds like something out of a Monty Python skit

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1970 T120R - 'Anton'
1970 Commando - 'Bruno'
1967 T120R - 'Caesar'
1968 Lightning - 'Dora'
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