LH carb proved innocent....!!

25 September.

Did a straight swap.  RH carb - known to be working ok, swapped with LH carb - status in doubt

So the RH cylinder ran absolutely fine - well ok - with the LH carb.

Whereas the LH cylinder now refuses to fire even with the proven RH carb.
 (it catches but won't go)
So basically have to conclude that the LH cylinder has other issues.

Fuel supply - checked by crossing over lines to opposite taps
 Compression - checked both all good
  Sparks - checked.
   Timing - checked static both sides and strobe on RH only (but see below)
     Carbs - both showing equally willing on RH cylinder but not on left

One anomoly still to solve - the strobe (inductor clamp type) does not pick up a signal from the LH HT lead - this has been an issue ever since new system fitted.  So I'm beginnning to wonder about the Sachse.  I double checked all the connections on install but maybe just maybe something is out of wack.

Loony Mikuni

23 and 24 Sep

After some worries about dirty fuel realised that using a biscuit tin to look at the fuel is a problem - the fuel seems to pick up from the tin and turns cloudy after a few seconds.  Re-tryed with a glass jar and fuel looks clear from both taps.  That saves some cash on a new tank over £600.

Anyhow after some faffing about (handwritten log below) left it still with a spitting failing LH cylinder.  Both carbs returned to standard set up except on bottom needle for richer pick up.

Float on

Next Mikuni tunes started today

Trimming slow runnning screw with air jet screw on seperate cylinders.

All going quite well until LH cylinder went off and wouldn't start

After a bit of head scratching, remembered the golden rule.

Spark plus fuel = BANG

Spark there with knobs on, so wheres the fuel?  Took the float bowl off.  Not much fuel - v low  probably below the jets.  Filled the float bowl direct from tap and screwed it back on

Pushed the go button.  BOOM!

Remembered that I fiddled with float heights 2015 when worried about rich running.  Next step - re calibrate float cut off.  Both sides.

You stupid boy.....!!

Here's a clue....
















Been listening to re-runs of Dad's Army

Think I should be auditioning for the part of ("Don't tell them your name") Private Pike.

So.....

Pulled out the beast, set the RH carb to match the left hand.

Turned it over in full confidence of an instant start.

Nada.  Nein.  Non.  Nichts.  Non. Null.

So before I ran out of languages, stopped and had a think.

The throttle cables seemed a bit tight, no play, maybe the slides aren't home.  Fiddled with both cables got slack back (problem in twist grip cable seating).

VOILA!!  instant start.  Followed by sudden death of LH followed up by demise on RH.

Checked sparks and timing.  OK.
Let's see what the fuel looks like in the carb.  Maybe they are gummed up with the gubbins that was supposed to seal the tank?

Took LH carb off first.  Not much fuel in there at all.  What there was looked a funny orange colour though.  Will have to think about that.

Took RH off.  Same story except the fuel looked a bit less coloured.

Opened fuel taps to look at color of fuel in tank.  NO FUEL CAME OUT!!

Felt a bit fuelish.  So I put 2 litres in, checked colour through taps, clear and no sediment.
Re-assembled everything.  Pressed the go button.

KABOOOM!!   Two hot pots!!  Felt ok on pick up so took her out for a spin.  Ran pretty well on choke.  Felt very weak off choke - nothing low down at all. Would pull away only with high rpm clutch slipping.

BUT NO KANGAROO on-off effects, no spitting and popping at all.

Brought her home to start work on carb tuning, but then it rained so left it at that.  The spark plugs looked a bit dark as if it was rich, but in truth the test run was way too short to get a useful reading.  But definitely no unburnt fuel out the exhausts now - unlike before the new ignition.  And both cylinders seem to be up to operating temperature (last year LH was always cool)

Excuse alert;
In my defence, the glass reservoirs in the fuel line (containing the secondary filters) had appeared to have fuel in them so I'd assumed all was well on that front.   But once the tank is empty the fuel in the line just hangs there without flowing into the carbs.  Deceptive.

And finally;
I'm going to need a new helmet those old ones just don't fit properly.  They are 30 years old!!  The prospects for a ride to an MOT before winter look promising.  Hope are up!

Mystery setback?

September 14th - 16th

Rolled the beast out for some more Mikunitunes.

Wouldn't start.  After an initial catch there was no sign of life.

Checked for sparks - ok

Checked with strobe - had to fiddle to get a light - seemed ok but not sure which mark was in view.

After some piddling about it rained.

September 16th

Put the carbs back to initial settings.  Still nothing catching.

So re-checked timing - miles out the disc must have slipped.

Put it back to standard - fired up straight away!

Analysis
At the end of the last session (thinking all was good) I screwed to new alloy distributor cap on and tightened it down.  Does it interfere with the timing rotor?  On inspection no sign of any circular marks that would indicate contact - so maybe I just need to be firmer with the grub screws tightening the rotor?

Hmm.  It's a bit worrying if the rotor is prone to slippage.

Next steps - - put the carbs settings back as per previous (needle max height, air screws 3/4 out) and start over.

Mikuni Tunes #1

11 September

Ok so it ticks over nice but won't pick up.

Initial set up - as supplied
Main jet 195
Pilot Jet 30
Needle Barrel 159P5
Needle 6DP17
Slide Cutaway 3.0

Today's log.

Starts first time.  Settles down to tick over off choke.
Gradual open throttle quickly leads to engine strangling, won't rev
Adjust RH cylinder only - air screw set to 1 turn out gave best results at lowest throttle screw
But no pick up

Needle jet moved up one.  A bit better

Needle jet up 2 - a lot better.  Would pick up through all openings and keep revving upwards.  A snap open kills it dead!

LH carb set to same settings - starts and runs clean at all openings but chuffs out on snap opening - think it's missing the pump action that the del orto's feature.

Unable to road test due to heavy rain starting up.

Feels like progress

Sparks Off!

Friday Sept 8th


Checked the timing with a strobe (Plugs out and earthed)

Connected the petrol

Fired her up - SPIT pop BANG!!

That can't be right - a quick review and of course I'd managed to time to TDC on the exhaust stroke.

DUH!!

Fixed that
Pushed the GO button

Fired up beautifully, ticks over like a slow heartbeat. 
Quiet. 
No knocks no ticks no taps - just rustles and paps.

Left it at that, no time left before supper - but now ready and up for for another sequence of carb tuning iterations!