The ignition's arrived...

[Le singe]

The ignition for my carburettor conversion arrived this morning,so that's another item hopefully sorted for the carburettor conversion.
The 40mm Bings are already to be fitted and I'm waiting for a few cable nipples to arrive to make the first throttle cable.
The ignition has a variable limiter plus an advance curve that hopefully won't be a million miles away from the optimum.
Next week,I should be able to visit the dyno for the 'before' curves,then I can start the fitting of the parts.
Just the fuel feed to be sorted,modify the feed pressure of the existing fuel pump to suit the carbs or fit fuel taps?
I like the simplicity of the taps,but the lines of the tank without them....
I've also acquired a spare set of cylinder heads,so should it be bigger inlet valves and ported heads time?
Or,how I think a question concerning modifications should be asked, 'Is there a good reason for NOT modifying the heads while the bikes off the road?'!
It will be interesting to see the photo of all the wiring and components that are obsolete after the conversion.

 

[sproggy]

I look forward to seeing the results!

I think I'd tend to fit an adjustable fuel pressure regulator and keep the pump in the tank. You could just use a simple return line from the carbs to 'bleed' excess fuel back to the tank, relying on the float needles, but that system can introduce fuel-starvation problems sometimes.....or flooding.

Larger valves tend to work better at higher revs and you might lose out further down the rev range if you go mad, but I can't think of any good reason for not porting and gas-flowing the heads while they're off.

 

[longdog]

I've also acquired a spare set of cylinder heads,so should it be bigger inlet valves and ported heads time?
Or,how I think a question concerning modifications should be asked, 'Is there a good reason for NOT modifying the heads while the bikes off the road?'!

Depends on what you are looking for. As a rule of thumb. smaller inlet valves mean higher gas speeds and equal more torque, (low and mid-range) while larger inlet valves will dump more mixture in for more top-end. You pays yer money.......... Either way, you should get benefits from a flow job whichever route you take. Personally, I can't wait to hear about the results!

 

[Le singe]

Fortunately I'm O.K. on the tuning knowledge as I had a small business in England specialising in tuning single-cylinder 4_stroke engines,
I've got the RS pistons and cams fitted at the moment and I really like the extra acceleration, compared to the standard GS, above 4.5-5K rpm.
I'd like to keep the existing bottom end but increase the acceleration even more at higher rpm.
An engine with a bit of a 'power-band' always feels more interesting to ride than one with a linear drive,IMO.
As to fuel delivery,the jury's still out, gravity feed and hide the fuel taps or retain the fuel pump and lower the feed pressure.
As I'm going for simplicity,the first option wins, but for ease of application the second is better.
Good job our house hasn't got any rooms with 2 doors or I'd never get out!

 

[Steptoe]

What work do you have to do on the main loom - what's in the kit ?

keep us posted

 

[Le singe]

The ignition itself is about the size of a normal bike CDI unit, it has 2, block- connectors.
One connects to the leads coming from just one of the Hall-effect sensors,the other block-connector has a power feed via the ignition switch,a feed to the coil and a feed to the tacho.
Nice and simple!
The mods to the main loom will consist of removing everything that is no longer needed,ie airbox air temperature sensor, wiring to the injectors,etc etc.
I like the simplicity of the airheads,but the refinements of the oilheads,this should be a good combination of the two.