Strange frame number Cappra VB

[Montynut]

Dave the VR tank has the breather in front of the fuel cap while VB has it beside the cap as does the tank in the picture.

That front wheel does not look like any Montesa whell I have seen

[cappra]

When I worked at the Montesa dealer, it was not uncommon for a dealer to buy a new model and use it as a parts bike as needed. Maybe it's:
a. importers/dealers left over bike that they got going by swapping motors and or frame.
b. Fitting a non Montesa front wheel assembly. (might be bultaco)
c. As mentioned, the frame stampings look somewhat suspicious.
d. For sure, it's a VB fuel tank.
e. Can't see the rear motor mount well enough to make a call.

[Kryckan]

Here is the picture of the rear engine mount and front wheel
I forgot to mention the engine has 5 speed

[Montynut]

That is not a VB series set of crankcases. The cases look like the earlier VA series cases. The crankcases changed for the VB series on.

All the 360/414's are 4 spd while the enduro 360's are 6spd. VR250 - VG250 are 5spd.

[Kryckan]

I've talked to Cenneth Löf ,he whas importer in Sweden in the 70's, he thought it was one of Hakan Andersson Old Gp bikes he got them directly from Spain
take a look at the engine mount under engine
http://www.google.se/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CE8QFjAE&url=http%3A%2F%2Fwww.vintageworksbikes.com%2FMiscMXPhotos.html&ei=k-uxUdn-Joq54ASz24CgCg&usg=AFQjCNEmPuLeJtKWsBsRQ1oUE56q78saNA&bvm=bv.47534661,d.bGE&cad=rja

[Montynut]

Well the bike on that site certainly seems to have the same strange engine mounts and crankcases although it is a 250. The VB250 & 360 have the same stroke and a 360 cylinder fits straight onto the 250 crank and cases at least in the VB250/360 model. The pipe in the pictures of your bike is certainly a VB360 pipe while the pipe on the Anderson 250 is a fabricated pipe.

You may have a rare piece of Montesa development bike history on your hands

The front wheel on your bike is a ring in by the look of it as the Anderson bike appears to have a normal Montesa front wheel.

[Kryckan]

I do not know if it is Hakan's bike, he had many, but evidence suggests that it may be, he drove Pade in 250 class and the 500 so maybe he just changed the engine?

[SON]

Great history, I have enjoyed this thread so far,
It particularly explained one thing,
Why VB Montesticles had the side plates that only fit 1 digit.
There prototypes where developed by single digit GP riders.
They didn't worry about us 2 digit types.

[cappra]

You just have to be a little creative!...

[GMC]

some more pictures. I discovered that it was magnesium when I would weld an injury, I have welded aluminum for 20 years so I can see the man differs from aluminum and magnesium

It does look like Mag.
Magnesium castings and aluminium castings are like chalk & cheese.
You can lay a bead of alloy rod onto a Mag casting that may look okay but it actually crystallizes at the join and as you say, with a pair of pliers you can pull the weld bead away from the casting.

Using another piece of Mag from something else to fill the hole is a good move but a waste of time if you used alloy filler rod, you would have needed to use a special Magnesium  rod for it to be successful.

Magnesium castings  also needs lower amps as it has a lower melting point compared to Aluminium and the Mag castings also welds a bit ‘fluffy’

[GMC]

The ‘66M’ stamping looks original
The ‘73M’ stamping looks haphazard ( a bit like the numbers I put on my own frames )

[JC]

66M0503A  - "A" for Anderson perhaps???
(Is that stating the obvious?)

Is it a lightweight frame? (compared to standard VB)

[GMC]

But then the frame engine mounts seem strange as the tube between the bottom frame rails at the foot peg mount seems to be curved and include an engine mount.

That tube looks straight to me but it seems to have some corner gussets to the rear of each side that give the impression in the photo that it might be curved.
Also I don't think that's an engine mount on that tube but a chain roller mount perhaps.

Wasn't the VA360 motor a side port and the VB360 motor a center port?
Or am I thinking of something else!

[firko]

I love these detective cases.....I look forward to the solving of the riddle. My money's on it being a works bike.

[cappra]

Pre 1977 250's and 360's were side port.