Carb setup for 850

htown16

htown16

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Getting ready to setup the carbs for the 74 850 I'm building. I'm planning on running non x-over exhaust headers and open peashooter mufflers along with a K+N air filter. I can't make heads or tails out of the 850 specs in the reference books because of the different models and muffler types. I realize these will just be a starting point and will need fine tuning. Here's what I'm looking for:
Main jet
Needle jet
pilot jet
slide
stepped or flat spray tube, 2 ring or 4 ring needle
Thanks
Htown
 
On my 850 I ran 32mm MK1s with the following:
main 260
needle jet 106
pilot fixed (0.016")
slide 3
needle 2 ring
straight spray tube
Jack Shemens type velocity stacks
750 spec. exhaust system with fluted baffle peashooters.
The motor was standard apart from 0.020" off the head & pushrods & a PW3 cam.
With this setup it ran really well until the crankcases cracked!

Martyn.
 
My totally stock 850 including cam and balanced head pipes but +.020:

140 mains.
pressed in pilot jets @ .016".
106 needle jets.
3 1/5 throttle slides.
notched spray tube.
four ring metering needle.
K&N filter.

Important to know that the notched spray tube NEEDS the four ring metering needle and the straight cut spray tube NEEDS the 2 ring metering needle.
 
I have the new 76 MK 111 with new stock 932 carbs and notched spray tubes with the 5 ring needles , 3 1/2 cutaway . Stock bean-can crossover exhaust. Running rich so moved the needle to top clip position . Would like it back to center position but sooty there. Ideas ? Fitted stay up floats to replace the nylon type with new float needles (aluminum ),
 
My setup is very similar to Matchless'. My bike is a Slimline racer with full Dunstall fairing.
The engine has lightened crankshaft balanced for the Slimline, PW3 cams, lightened rockers, flowed head, Dunstall silencers without balancîng, longer splayed admission manifolds, carbs rubber mounted, Pazon.

Amal 932s with velocity stacks
Main jets: 260 for track, 240 for road
Needle jets: 106
Slide: n°3, bronze.
Standard Norton needle at richest (needle up, clip down)
Notched spray tubes

The bike has been clocked at around 230Mph at Dijon circuit in May this year. :mrgreen:
 
Whoops, yes , the needles are 4 very thin notch rings at their tops , above the clip settings. Went for another rip today and returned to see gas dripping from the left bowl. Left spark plug rich and right lean so pulled the bowls to peen the float pins into place this evening.
 
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