Ok then.....
after hijacking Bert's thread in Workshop here
http://xs1100.com.au/forum/index.php?topic=1594.0I have been to Bourke and back with the BS36 carbs fitted and have the following to report.
On receipt of the BS36 set (off an XJR 1200) I stripped and cleaned same, replaced all gaskets, O rings etc. I replaced the Main Jet (95) and Pilot Jet (40) with the Jets from my old BS34's (140 Main and 45 Pilot) All others remain stock for the XJR1200 units.
I set the fuel levels at ~5mm after frelling around with float heights - first time I have set fuel levels as opposed to float heights (I must have been lucky with my old BS34's that all the floats displaced the same volume of fuel)
So - the machine pulled well down low but was not keen to rev over 7k revs as discussed in Berts thread above.
After making a great contact at CONCOURS in Fred from Pro Cycle Dyno at Slacks Creek I bit the bullet and took my machine down to him on Monday last for sorting once and for all.
The optimal air/fuel ratio (AFR) is around 14.7 (
http://en.wikipedia.org/wiki/Air-fuel_ratio)
A lower ratio is richer and higher is leaner.
The red lines and text on the graph above is with my 140 Main Jets - at around 7k revs my AFR approached 17 - too lean to ignite and so my mis-firing (rather like a rev limiter)
Fred's first guess at increasing the Main Jet by 4 sizes to 160 proved close to perfect as the blue lines and text on the above graph show.
On Fred's advice I have dropped the needles to the second top groove.
He commented on how strongly my engine pulls at low revs and midrange and that the HP and Torque figures are a credit to the engineering of my engine.
So the upshot is this
BS34 to BS36 = more air = more fuel = bigger Mains......the +4 sizes being a rule of thumb according to the expert.
I will be away on the bike on the weekend and will be able to report on fuel economy next week.
Oh - and I have re-routed that throttle cable too.....
