Hi, I bought a plunger gearbox at a Kempton Park autojumble; it's generally complete and the shafts and gears are in fairly good condition. The kickstart return spring (picture below) appears to indicate that it was manufactured between 1946 and 1949. However, I can't see any means of attaching the spring to the quadrant that was included with the gearbox and the quandrant I have (picture below) looks different to the one in the diagram in the workshop manual for this model (picture below with apologies and thanks to whoever owns the copyright)
I have the newer type spring that hooks over the rim of the quadrant and there is no way that it will fit in the front case.
Have I got a quadrant from a later box?
Thanks
John
Hi,
The spring looks like the inner end had broken off so would not hold on the kickstart quadrant even if it was the proper one.
Can you determine from the rest of the gearbox which the wrong part the spring or the quadrant?
Try assembling the outer cover with the quadrant in place and see if it goes together properly, if not then the latere
My wife's '51 Flash has a quadrant like the one you have shown with the coiled wire type spring.
Dave.
This quadrant should definitely be fitted with a coiled wire spring that hooks over the notch in the toothed arc. I'm not an expert on pre-unit gearboxes but I've found it difficult to identify one that takes a clock-like main spring as shown. Out of interest, what gearbox is the parts book extract taken from?
Is there any chance of a few pics of the outside of the gearbox, especially of the cover, which will hopefully confirm what type it is?
Thanks Dave and Spaceman
The manual extract is taken from the Illustrated Workshop Manual 500cc and 650cc Twin Cylinder Rigid and Plunger Sprung Rear Ends - A Group, supplied by Bruce Main Smith via the National Motorcycle Museum.
I too thought the internal end of the spring was broken but looking at examples on ebay, it's not unlike the spring for some bantam and Triumph models. I can assemble the covers without the spring and it all fits together fine but if I try with the later spring (that hooks over the quadrant arc) it doesn't fit. Which leads me to believe, maybe without convincing evidence, that the quadrant is wrong as there seems to be only enough space in the casing for the clock type spring. I'll post some pictures of the cases tomorrow and see if anyone can shed light on it. Thanks again. John
Here are some pictures of the outer casings.. I am convinced it's the correct spring because of the peg inserted in the case to secure the outer end of the spring.
Thanks
John
Hi,
3 images of a spare cover. You will see that there is an attached lug for the coiled spring to be secured to and held by a nut on the outside. This is also found on the later gear boxes. Could this be a C12 outer cover?
Dave.
Both outer covers look to have the same casting number of 67-3020? The part number for the plunger gearbox outer cover is 67-3021, so are they are the same casting with Johns cover having a peg instead of the Kickstart spring screw (02-3178) and locknut (27-4401)?