I have run out of things to do without starting her up!
I still need to check the shimming of the oil pump, but according to Haynes, this needs to be done with the engine running.
Bleeding the oil pump also needs to have a running engine, so the next step is to mount the fuel tank, and fill it with, initially, some premix at circa 40/1 ratio.
I had 2 viable fuel taps.
The one from the donor bike does not turn off sufficiently, leaving a trickle of fuel running down the tubes.
My memory of standard carbs is that with the bike on it’s sidestand overnight, the fuel used to run through the left hand carb and into the crankcase.
If this is a thing, I’ll need the ability to turn off the fuel at the tank reliably.
The tap from the parts bin only seem to flow fuel from one outlet.
This is a mystery, as the interior of the tap appears to be as clean as a whistle!
<edit> This also happens with my brand new tap, so seems to be something to do with flow dynamics inside the tap bowl.
This tap also does not turn off the fuel sufficiently.
Rather than waste any more time messing about with half usable parts, I invested in a new TourMax dual output fuel tap.
With that fitted, it was time to fill the tank with 5 litres of unleaded, and 125cc of 2T oil, and give it a kick…
…whereupon it starts 3rd kick! Huzzah!
Three things are apparent immediately.
1) The right hand carb is leaking from the float bowl gasket
2) The engine won’t run without choke
3) The oil level switch doesn’t work
The first must be dealt with straight away, (with a new gasket), and may be affecting the second, which also may be simply the tickover screws.
The third is inconsequential at the moment. I have a spare switch which I swap in later, although it could be a wiring problem, even though I tested the loom by shorting and un-shorting the contacts when I built it.
New gasket fitted to the RHS carb, and I have more clarity on the carburation issue.
I have upped the tickover screws and I have a viable tickover while on choke.
The engine is warm, the temp gauge is at circa 1/8th of its travel.
Closing the choke means the engine bogs down immediately, and won’t tickover or respond to even fractional opening of the throttle.
With the choke on, the engine bogs down with fractional throttle openings until the revs rise to circa 3000, when the engine catches, and seems to behave normally.
Before proceeding, I want to eliminate every other possible cause, so I’m going to dig around in the parts box to find an original OEM Mikuni choke plunger, and I have a pair of new NGK B8ES plugs to fit.
Oil pump shim measurement.
Meanwhile, notwithstanding the erratic behaviour of the engine, I have managed to turn it off when the oil pump is at its fullest extent, so I can measure the oil pump shim gap as being between .10 and .15 of a mm.
This compares to the text book setting of .15mm.
This seems accurate enough to the limit of my ability to measure it at present.
(and sufficient for running in which is all this engine will get before the bike is dismantled again)
Given that all of my oil pumps are nearly 40 years old, one of them is going off to @Arrow who posts on the RDLCCrazy forums, for an overhaul.
With new plugs, and an OEM choke plunger, the tickover on choke seems much more regular.
BUT, when the choke is off, the throttle becomes unresponsive, and the bike runs on the right hand side only.
i.e. the left carburettor is not passing sufficient fuel or air. the mixture is wrong.
Drilling the balls.
It seems I will need to perform the much heralded “Clearance behind the brass balls” manoeuvre to clean the air corrector circuit in the carb.
Obviously, while the drill is out, I’ll do both carbs.