ET: Engine (Twin) Fuel and Carb Settings

bmetcalf

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According to the engine build sheet 7:1 flat tops are listed. I did look at them with a bore scope and they are indeed flat tops with 2 valve relief pockets.
I don't think the avgas is worth the money. The bikes were designed for wartime rationing low octane pool petrol.
 

Bill Thomas

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Have you an oiling problem that's wetting the plugs, I would not want to go softer / hotter than N5.
Does it smoke at all ?.
Once a plug has got wet etc, I throw them in the bin.
 

greg brillus

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As soon as the engine fires pull both choke slides to the rear of the machine.........probably banging in the exhaust due to an overly rich mixture..........N 5 C plugs should be fine and not soot up easily unless it is over rich. the snatchy clutch will be broken springs in the shoe plungers most likely, but that's another job for another day. It sounds like either your slides are wrong, cut away too small or the float levels are too high.
 

vibrac

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I stoped giving advice when I read this bit "I am running the bike on non-oxygenated, leaded 110 octane fuel" all us limeys can say is no wonder the US is called 'land of the free'
 

greg brillus

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they've banned it here in racing now........unless you have a big compression engine, there is no point in using avgas, in fact long term use will do more harm than good, very corrosive on valves, guides and so on, plus it will readily block up a muffler as well.
 

Bill Thomas

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Mine was fine for years on 12 to 1 on the track and same bike on the road at the same time,
But needed 100 octane and 26 degrees advance, "D" Distributor.
 

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Bobv07662

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Thank you all for your input, it's been very helpful. I do apologize for the good old fashioned race fuel we have available here in the States. (Not Av-gas).
The bike does not smoke at all and after last night's ride I checked the plugs and they look fine.
I had previously made up an inspection tube to look at the float level on the pre-monoblocs, they are about 1/4 inch below the jet and not leaking either. The bike does respond to adjustments to the pilot circuit and appears to be happier at idle the richer I make it, so I believe lean due to air leaks around the unsealed spigots as suggested by Robert Watson will be my next thing to look at.
Today was fine tuning the rear ride height for the Dave Hills center-stand.

Fuel I'm presently using...https://vpracingfuels.com/product/motorsport-105l-ms105l/?c=217
 
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