Topic: 75 CB550 K1 timing issue

[esnyder6]

I just discovered with my new timing light that I can't even get close to the firing point on the spark advancer at idle, even by "advancing" (which i assume to be turning the points plate counter clockwise) as far as it will go.  it will run steadily at that point and idle ok, but it just really seemed to be lacking power.    I replaced valves and piston rings almost two years ago.  It was my first rebuild so i'm assuming i've done something wrong.  I remember setting my cam correctly with both lobes down on cylinder 1 at TDC compression stroke, and i've checked to make sure the tappets arent under pressure and have their required play, which they do.  I'm just wondering if my camchain has slipped a couple of teeth or something, just enough that you can't tell by checking the tappet/rocker arm tension?  how else could the timing be so far out of whack?

here's what i'm looking at when timing at an idle (with points plate turned as far counter clockwise as it can go. (same for adjustable plate for 2/3): (at 2500-300 rpm it is obviously way off at the advance marks as well) 
         
                |___|___|   <-- mark on crankcase
 |  |             |  |
T F  1.4         



Anybody with any advice, it is much appreciated!

[w1sa]

Welcome.

Are the 'advance mechanism' springs attached ?   ........assuming the static timing and points gaps etc. were set correctly, the advancer might be the problem.

You wouldn't normally get the dynamic idle timing/advance in that position, unless the advancer mechanism was malfunctioning.

Pull it off and inspect........re-install when correct and set/adjust the points/plate/static timing by the book.

Don't restart/run the engine until you're satisfied it is set correctly

[bollingball]

I would recheck the points. What brand name are they and how old are they?
Ken

[bryanj]

You DO NOT use a Timing Light (strobe) to set the timing at tickover----ONLY to check the max advance AFTER setting the points gap to 14 thou and setting the timing with a bulb across the points as per the manual

[dave500]

your top end cam etc timing will be ok,you dont mention if youve just set the gap etc?once the points rubbing block has worn too far youll be hard pressed getting the timing correct,,bryanj is right on running the engine up to speed and checking how far it fully advances,,you must check both sets,,they must be the same,,have you considered an electronic unit?

[trueblue]

Some of the non-genuine points have issues hitting the mark as far as timing goes.  Your cam timing doesn't affect the ignition timing on these engines.

[Spanner 1]

Agreed, cam timing has no effect on ign. timing, as ign. is driven from the crank........ crappy points will give your symptoms....
BTW.... 'tick-over' is British for 'idle'   ( See Bryanj above  )..

[bryanj]

Thanks Spanner, Idle over here means lazy!!