Madass140 Single Throttle Cable Amal Kit

johnm

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sorry to hear about the interference issue. on my first install, I reused the original carb screws, but was uncomfortable with only a couple threads engaged because of the thickness of the top plate, so I opted to go with longer screws. longer 2BA originals were pricey, and couldn't find any local U.S. stock, so I opted to go with the 5mm - local ace hardware stock. I had the taps, so it was only a couple dollars to switch. off the top of my head, i'm thinking the thread pitch was almost identical and the diameter was only .010" larger. i'm thinking part on the reason why I had to enlarge the mounting hole was because of the hardware switch. it's not relevant to your issue now, but here's a pic of the area - hard to tell, but I probably have a good quarter inch from the cable pillar to the tank --



one final thing, pretty sure I have a non-stock throttle grip, it looks to be some sort of 1/4 turn assembly. when I installed the cable, there was no way to use the cable adapter. am I over looking something and do I need that part, or is it OK as is? it seems to work ok without the adapter, and the cable end fits the twist grip.
Thanks. That's a useful photo and I will compare with mine today. I'm using the original 2 BA screws and fitting went fine apart from changing the throttle nipple. Silver soldered a new nipple. The cable adapter was too large in diameter to fit into my throttle grip.

I imagine there have been many many types of throttle hand pieces out there over the years.

If I can find a fix to the clearance issue I'll get some longer 2 BA cap screws. Allan keys are much easier to use on the carb tops.
 
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With a metal tank, and not too much of a clearance problem, some judicious "denting" may do the job if you don't object to doing that to the tank.
 
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I have a 74 mk 2 (jun) Roadster, and no interference problems with Dons gantry.
Maybe new inner tank rubbers (that sit on the top frame rail) are in order ?
 

johnm

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Definitely rubb
Its a very nice tank

Ok. Its not going to work.

Tank tunnel width at appropriate point 116 mm or 58 mm either side.

Outside edge of pillar from centre line of frame tube. 59 mm. Definite clash.

The bike has brand new CNW isolastic installed so the engine is positioned correctly

I would have to lift the tank 25 mm minimum to clear

Dòes anyone have an original Roadster tank they could measure the tunnel width for me.
 
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Blaisestatiom is more correct. The tank might be raised using thicker foam pads. The rubbers on tbe tank studs are just to keep it from rocking, not support, according to past posts that made sense.
 

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The cable anchor is hitting the inside of the tunnel ?
 

johnm

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Blaisestatiom is more correct. The tank might be raised using thicker foam pads. The rubbers on tbe tank studs are just to keep it from rocking, not support, according to past posts that made sense.
Would have to raise it an additional 25 mm over standard. I just tried it and it raises the back so high that the front actually hits the steering head unless I put something like 12 rubber washers on it at the front. Which of course means the stud is too short
 

johnm

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The cable anchor is hitting the inside of the tunnel ?
The pillar is hitting thebinside of the tunnel

20200115_110922.jpg 20200115_111010.jpg
20200115_110922.jpg
20200115_111010.jpg

The cable anchor is hitting the inside of the tunnel ?
Plenty of measurements for the Roadster tank here, thanks Joe and co.

https://www.accessnorton.com/NortonCommando/fuel-tank-mounts.28729/
Unfortunatly all the information here is for the tunnel at the front. I'm looking for the measurement at the back by the taps
 

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I have a 74 mk 2 (jun) Roadster, and no interference problems with Dons gantry.
Maybe new inner tank rubbers (that sit on the top frame rail) are in order ?
good point. on my installation, everything associated with the tank mounting was new.
 
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this may be a dumb question, but is your tank perfectly centered on the frame? it wouldn't need to be off by much to cause interference. just grabbing at straws.
 

johnm

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this may be a dumb question, but is your tank perfectly centered on the frame? it wouldn't need to be off by much to cause interference. just grabbing at straws.
Yes it is centred. I can push it 10 mm off centre to get clearance.

But at the end of the day I can't fit a 59 mm object into a 58 mm space.

So looks like I'm back to standard
 

johnm

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One solution is to flip it over. The Norton n engine is offset in the frame to the left. By flipping the lift mechanism to the right hand side you have way more clearance.

Can you think of any reason it was made to fit on the left side which has less clearance?

I need to make a new plate and change round spacers etc. But that should not be much of a challenge. I have access to a workshop that makes DOHC Velo engines from scratch
 

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You need to consider some things.

The part is made via CNC so a program glitch is unlikely on one item.
(I can measure the gantry I have as a comparison)

No one else seems to have a clearance problem and I believe I saw somewhere 100 or so have been made.

Its easy, something is not as it should be and even if the unit can be used as per you say (cable on the right) , that original something will still be there if excluding the bracket.
#
Remember when I was chasing an oddity with my replacement 850 crankshaft and it turned out to be the main bearing outer race contacting the crank cheek from the factory due to a 0 to 0.019" discrepancy.
Once found, not so hard to fix with some surface grinding.

The problem might be something simple or overlooked.
 
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