Tuned 395xp - ignition timing

[bmp01]

That looks like the right coil Spud. It's done all of its advancing between 0 and 3000 rpm, just 9 degrees, flat timing there after. Don't know why I saw 30 degrees difference between 1000rpm and 3000rpm. Also no limiter acording to the data.... I wonder if I've been caught out by shades of blue and the saw needing a retune now the airleak is fixed ??? Tomorrow...

Googling SEM and AM44 also throws up a hit on acresinternet.com for the 394xp which they say uses the SEM AF44 coil. Date code on my coil is 2007 W47 (a bit late for a 394 part?) My 395 is an 2008 model - those 2 dates fit together quite nicely.

 

htb - thanks for the offer,  not sure if you'll be able to see the part number without removing the coil though .  See picture,  the part number info is below the coil laminates when fitted.

 

Edited January 12, 2020 by bmp01
Colour and tuning note added

[spudulike]

That looks black to me??? Not the bright blue colour I was expecting?

How are you measuring the degrees with a strobe? and how did you get TDC? Post a pic as I know how I got there and it wasn't easy! Thinking about it now hurts my head

[htb]

Black on mine same as yours.

[bmp01]

1 hour ago, spudulike said:

That looks black to me??? Not the bright blue colour I was expecting?

How are you measuring the degrees with a strobe? and how did you get TDC? Post a pic as I know how I got there and it wasn't easy! Thinking about it now hurts my head

Fek, I've jumped to the wrong conclusion then. In my defense its not black it's navy blue (compare to the ht lead in picture). Certainly not bright blue though, Google educated me on the shade of blue for a 'blue' coil.

So remember I have a 3mm dowl pin in the flywheel where the original key used to be, I'm checking what I have; not starting from a complete unknown.

Finding TDC, degree wheel fitted loosely to f/wheel, exhaust off, piston crown below top edge of exhaust port. Drill blank in the gap, rotate crank to cause contact - note angle on timing wheel. Rotate engine through BDC, cause contact in other direction - note angle. Hold crank still, rotate degree wheel to get equal angle before and after TDC. Repeat umpteen times to check, recheck blar, blar.

I picked the top edge of the top lamination on the coil for the above. I just marked the flwheel with TDC, 5,10,15,20,25,30 DEGS BTDC.

Degree wheel off, engine rebuilt, engine started, starter cover removed while running and strobed the result. Pictures on next post.

Edited January 12, 2020 by bmp01
Corrections

[bmp01]

Idle speed, strobe above camera to minimise refection. You can see the 10 and 30 marks quite clearly 20 is right where the fin is.

Edited January 12, 2020 by bmp01
Second picture added

[bmp01]

Less good picture, engine being cranked with battery drill. You have to use the geometry of the flywheel to establish timing. Second picture is with the engine stationary as I interpretted it...

[bmp01]

I should make it quite clear - the chain is OFF the saw for all this messing..... Bar and clutch cover on for stability and to shield the other moving parts. My 11 year old son was in charge of camera, that was scary enough for me.

 

[bmp01]

41 minutes ago, htb said:

Black on mine same as yours.

Thanks.  Did you get to see part number as well ? No worries if not.

[htb]

Will check tonight when I get back home.

[spudulike]

OK, sounds round about right although I used a screw in piston stop and did the same, rotate one way and then the other then rotating the degree wheel until both degrees clockwise and anticlockwise match and the middle point will logically be TDC. I reckon we are now in the 0.00001% of the UK population that know what the feck we are talking about!!!!

Interesting you marked the flywheel and used a static point on the saw, I made a graduated scale and screwed it around the flywheel and used a mark on the flywheel to get the timing. The 066 has a nice gap over the top of the flywheel which worked fine for me.

When I did this, I didn't compute that as soon as I rotated the flywheel on the crank, the scale would need redoing and ran 50 degrees for a brief moment - it didn't sound too good. I think for your method, you won't get this issue but it hurts my head working it out, similar method though.