VHB 29AD

[Mark3Don]

Cheers,
I've recently purchased a VHB 29AD carb. It has a 7454.50 throttle slide. This will be going on my 69 350 Mark 3D. The bike originally came with the VHB carb but had a 7454.40 slide.
How much of a difference will the .50 have over the .40 slide? Can it be used without issue or should I have the slide machined to a .40?

Thanks,
Don

[Jordan]

The .40 denotes a 4mm cutaway, or the front is 4mm higher than the back of the slide.
The .50 is 5mm.

A larger number will result in a leaner mixture in the approximate range of between 1/8 to 1/4 throttle opening.
A smaller number gives a richer mixture etc.

You could easily enough increase the cutaway from 40 to 50, but not sure if you could chop the back of the slide successfully, to go from leaner to richer.
If you do any alteration, do a favour to some future mechanic and re-mark the slide with the new size.
Better still, maybe you could find the slide you want?

[howlndog]

This photo illustrates what Jordan was describing. In this case, however, the backsides of a #40 and #60 slide are shown.

slide_vhb_1.jpg

photo source: http://www.thisoldtractor.com/moto_guzz ... __vhb.html