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650ss throttle an choke cable routing

Submitted by tom_steele on Sat, 18/02/2017
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Heavy Twins

anyone got any tips regards routing on a 67 with 930 amals :)

Submitted by kevin_bell on Sun, 19/02/2017

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Previously tom_steele wrote:

anyone got any tips regards routing on a 67 with 930 amals :)

Cable Routing 101: As smooth as possible. Wink

Kevin

Submitted by howard_robinson on Tue, 21/02/2017

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Previously tom_steele wrote:

anyone got any tips regards routing on a 67 with 930 amals :)

Hello Tom - Interesting that you point out you've got a pair of 30mm concentric on a '67 650SS. Do you know if the separate induction spacers have an internal diameter of 30mm to suit or if there is a step ? Similarly is there a step at the input port on the head ? I have a few 650 engines in various states of tune with the standard one having a pair of 1 1/16 inch Monoblocs and matching induction spacers with tin sleeves reducing the input port diameter on the head to suit. My full-race Curley head has 1 3/16 inch Monoblocs and ports to suit down to an enlarged inlet valve. Your 30mm equates to 1.2 inch that is slightly larger than 1.1875 inch (1 3/16 inch). I am intrigued how they came up with this configuration......... My Commando Combat also used 30mm Concentrics whilst my Mercury breathes thro' a single 28mm Concentric. Does your 67 have the large diameter exhaust pipes (1 5/8 inch all way to silencer) ? Cheers for now, Howard

Submitted by tom_steele on Tue, 21/02/2017

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Hi Howard it actually came out bang on head / spacer and carbs' I used the longer inlet manifolds, That looked original to the bike in the box of bits, it might have been tweaked a bit previously as the guy I got her off owned her since new and really knew what he was doing, didn't run the smaller spacers as try as I might after about 4 different sets of studs they all needed lots of extra gaskets, with the longer ones it was just the one so that worked out perfect.

Left the long induction spacers off the bike,

Shame I didn't take some pictures as I did it, Ill have to check on the pipes can't remember for the life of me think they are 1/ 5/8 inch though got them From Les at Norvil.

Sorted the cable routing at weekend took a few goes haha but seems pretty nice now

Submitted by martyn_watson on Tue, 28/02/2017

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My 650ss has a pair of 30mm mk2 amals, I assume they must have been fitted as a kit of parts, the inlet stubs are nicely turned and the spacer bar and the choke linkage look well made.

I got the bike of a fella that had last had it on the road in 1987 and he said the carbs were on there when he got it. I've had the carbs off to clean, the PO saying he parked it and left it when it started running on one cylinder. the inlet is smooth all the through, no steps. The inlet stubs are fairly long, you couldn't fit a rizla paper between the belmouths and the tinware. No air filters.

It was imported into New Zealand for the police. Has the smaller diameter later header pipes.

No doubt it's been thrashed mercilessly by the NZ cops in hot pursuit of kangaroo smugglers, but it still goes very well.

Submitted by howard_robinson on Tue, 28/02/2017

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Hello again Tom - The longer induction manifolds are usually paired with Monobloc carbs whilst the shorter ones were introduced with the concentric set up. They were only a few millimetres shorter as you know so it shouldn't have too much effect on the carburetion. If anything I should think it may accelerate a bit slower owing to the increased lag in the system but the top-end may be a little greater. You'd have to be on a track to notice anyway. The larger diameter pipes employed will reduce the back pressure somewhat so that is probably why they increased the diameter to 30mm with the concentrics. Is it quite thirsty or haven't you checked that yet ? Cheers, Howard

 


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