Making A Little Progress (with pics)

[guzzijon]

OK, I'll check that next. Thanks again for all of the information!

[DewCatTea-Bob]

" I'll check that next. "

____ Still waiting to hear-of what you found.

____ Although less likely to stay unaltered, another difference between the two motor-models is that the Monza came stock with a 17-tooth drive-sprocket whilst the other motor employed a 18t front sprocket.
So which sprocket your Monza has could be of interest, along with the mileage on that Duke.


Hopeful-Cheers,
-Bob

[guzzijon]

OK, I checked and found that there are just two wires within the conduit for the alt. cable. I couldn't tell you the color because it's all too degraded. I even peeled back the conduit more towards the middle and I couldn't tell what color. But bottom line, just two wires.

It is also missing the front sprocket and I have no idea of the mileage, no gauges on this thing. It was turned into a dirt bike a long time ago, ridden hard and then left in a backyard with caked-on mud for 30 years.

So it's looking like it's a Monza that someone added the big-valve, big port head to then?

[DewCatTea-Bob]

" I checked and found that there are just two wires within the conduit for the alt. cable. I couldn't tell you the color because it's all too degraded.
But bottom line, just two wires. "

____ I gather then that they were both the same shade, and therefore must have been the most common yellow wire-lead pair.


" So it's looking like it's a Monza that someone added the big-valve, big port head to then? "

____ Yes, pretty-likely the original Monza bottom-end along-with the complete M1/Mk3 top-end which you removed from it.


Content-Cheers,
-Bob

[guzzijon]

Wonder if it has a Mk3 cam as well? IF the cam lobes are symmetrical it's likely a stock cam but if they're asymmetrical it's something else. What are the valve sizes? Matt

I got the cam out of the head that came on the Monza last night. There is a red paint daub on it. Does this indicate a MK3 cam?

[DewCatTea-Bob]

" I got the cam out of the head that came on the Monza last night. "

____ Is that the same Monza that was determined to have a Mark-3 top-end on it, (or am I mixed-up with some other) ?


" There is a red paint daub on it. Does this indicate a MK3 cam? "

____ The real/original 'Mark III' camshaft was the one with red-paint (spotted on the threaded-end of it's shaft). _ Whilst the 'Mark-3' & the Mach-I camshaft was with a gray-paint mark.
In either case, the paint-mark is rarely left it tact (within a fairly well used engine).
Got any pix of that cam ?
__ So to help tell if your top-end is a stock/untampered-with set, we need to know what size it's valves are,,
is the intake-valve 40 or 36mm ?


Duke-Cheers,
-Bob

[guzzijon]

Hi Bob, yes this is the 1964 mystery bike (probably Monza) that came with the big-valve, big port top end on it. It has the 40mm intake valve, 36mm exhaust valve and the 29mm intake port. I will post pics of the cam tonight.

[DewCatTea-Bob]

" It has the 40mm intake valve, 36mm exhaust valve and the 29mm intake port. "

____ As I recall, that top-end had the high-dome piston with the larger cut-outs intended for that valve-set size, so all THOSE details indicate you have the Mark-3/Mach-I type top-end EXCEPT your "red" camshaft ! _ As the camshaft that's original to that top-end is the GRAY-cam.


Dukaddy-DUKEs,
-Bob

[guzzijon]

Here's a picture of the camshaft showing the red paint dab:



Here's a picture of the camshaft showing the lobe profiles:



Here's a picture of the top of the (stuck for now) piston:

[DewCatTea-Bob]

" Here's a picture of the camshaft showing the red paint dab: "

____ That's not where the factory-placed identifying paint-color is located on the camshaft !
I have no idea what that red-stuff is doing (where it is) on your cam, (as it shouldn't be there!).
__ Do you have a pic showing the shaft-end where the threads are ?



" Here's a picture of the camshaft showing the lobe profiles: "

____ It's not easy to be certain but, that appears to be the gray-cam (rather than the red-cam).



" Here's a picture of the top of the (stuck for now) piston: "

____ Okay, it now seems I've confused your piston with another, as that's not the same piston I was thinking of...
As that's a MC-piston and not EITHER stock-type high-dome Borgo-piston.



Dukaddy-DUKEs,
-Bob