JB Weld removal ;)

xbacksideslider · Dec 12, 2019

These are my original 932s with the “racing” bells JB Welded onto them. I ran this “secret weapon” set up for at least 15 years inside a stock ham can. You have to raise the ham can to get adequate clearance at the top of the bells’ inlet horns. The rubbers are stock placed on the inside of the ham can instead of the outside. Black silicone seal must be slathered between the ID of the rubbers and the OD of the bells to get a good seal.
Of course, the front panel of the ham can gets trapped between the bells and the carbs.

When the carbs finally wore out, they went onto the shelf from which I just pulled them for the pics below. I had the same problem then as Mike has now. Someday I’ll remove the PWKs I replaced these worn out 932s with and do it again but with Premiers.

MexicoMike · Dec 25, 2019

Thanks John, great stuff!!! Only thing I'd have to do, since the stacks are already JB'd to the carbs, is enlarge the ham can holes slightly - the stack bells are just a tad larger than the holes in the ham can - easily done with a Dremel. I've also been fooling with a KN filter that, I think would also work, basically doing it the same way - with the stacks inserted the filter with plenty of silicone seal as you described. I'll definitely do one or the other but I like your ham can!

MexicoMike · Dec 25, 2019

John - been out in the garage this afternoon, modified the ham can back plate holes to accept the stack mouths and drilled new holes so the can could move upward enough to clear, as you described. I'm going to try wrapping electrical tape around the stacks at the point where the ham can rubbers will go around them with the rubbers mounted in the normal way and then put a clamp around the rubbers/stacks. If that doesn't work like I hope, I'll duplicate your method with the rubbers mounted backwards.

Hmmm...on looking at your pics again, I am going to duplicate your method, not futzing with the electrical tape.

Atlas Commando · Dec 26, 2019

That's a nice solution. The only thing you're going to lose is the killer looks of the open velocity stacks.

MexicoMike · Dec 26, 2019

Yeah, but the first thing I discovered after installing the stacks/putting everything back together was that on my Fastback, I couldn't see the stacks anyway!

Frankly that was the main reason that I decided I needed an air filter - if I couldn't see the cool-looking stacks, then might as well have filtered air going to them!

xbacksideslider · Dec 26, 2019

Glad it worked out for you Mike. I found that R&R was easiest by way of intake manifold Allen head cap screws

Craig · Dec 26, 2019

Yes , glad you almost Happy with the new setup , sometimes it nice to hide performance enhancement , maybe win your self a coffee/beer next time a smart guy wants a little dig ...

MexicoMike · Dec 30, 2019

xbacksideslider said:
Glad it worked out for you Mike. I found that R&R was easiest by way of intake manifold Allen head cap screws

How did you adjust your throttle cables/slides on the carbs with the air filter in place? Since the filter cannot be removed with the carbs mounted, and the stacks are JB-welded to the carbs, I'm having a hard time figuring out an easy way to do that. Only thing I can think of is to set cables/slides with the carbs/manifolds NOT bolted to the engine and then mount them, ensuring there is no change in the tension/alignment of the throttle cables. Am I missing some easy way to do this? I do not have a vacuum gauges setup...I used to but gave it away when I sold my last carbureted 4 Cyl bike (back in the 90's).

xbacksideslider · Dec 30, 2019

It’s a two-step.

First do a mock up install without installing the air filter and exterior screen.

You are probably familiar with this method where two 6” ( + or - ) pieces of thin welding rod are placed under the slides’ front cut aways such thatthe other end of the rod is visible at the bellmouth. Now, even the slightest opening of the throttle indicates which slide lags and which leads in opening.

You may have to slip the two rods’ ends under the cut outs before you mount the filterless carb set. This because the back plate of the ham can likely will be in the way.

Before you synch the two slides, simplify the cable routing and take note of the cable layout and then after synching with the rods, listen for the slides” clicking synchronicity.

Now you can R&R the ham can filter and screen. Verify by listening for the same clicking synchronicity.

MexicoMike · Dec 30, 2019

Thanks - that's essentially what I was thinking of. It would be nice to use a device that would link both carbs directly - like the Madass throttle setup - but unfortunately, my Fastback tank from Burton Bike Bits will not drop into place over the kit. The BBB FG tank is identical externally to the OEM Norton Fastback tank, but apparently the underside is somewhat different and won't clear.

xbacksideslider · Dec 30, 2019

I've also vacuum balanced with clear tubing, gas/diesel, and an intermediate catch bottle. Aquarium valves to reduce the strength of the pulsations. Simple concept but difficult in execution

JB Weld removal ;)

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