Honda-SOHC

SOHC.co.uk Forums => CB500/550 => Topic started by: Popstar on October 27, 2021, 03:10:14 PM

Title: 71 advance/retard mechanism
Post by: Popstar on October 27, 2021, 03:10:14 PM
Hello I’m just about to strip my 71 advance and retard mechanism and I’ve noted that there is an index mark on the outside of the central cam,Should the index mark lineup with the timing mark(hole) indicated by the Biro pen on the right hand side of the plate or as close to it as possible, also does anyone notice anything out of the ordinary on this advance and retard unit it is the number 323 which I believe is correct for the 71 model.
Title: Re: 71 advance/retard mechanism
Post by: Nurse Julie on October 27, 2021, 03:20:13 PM
It can only go one way for it to function correctly.
Title: Re: 71 advance/retard mechanism
Post by: K2-K6 on October 27, 2021, 05:38:52 PM
As above description,  it can fit two ways with the right way firing all of the cylinders correctly at TDC, the other assembly fires all the cylinders at BDC and so won't start.

It's only a case of removal and refit the opposite if you did get it wrong, so not a massive show stopper.
Title: Re: 71 advance/retard mechanism
Post by: deltarider on October 27, 2021, 05:43:25 PM
Or simply swap the blue and yellow wires.
Title: Re: 71 advance/retard mechanism
Post by: Popstar on October 27, 2021, 06:31:00 PM
Yes it is running like a dog however that may be something else i need to look at if the above photo is correct.
Title: Re: 71 advance/retard mechanism
Post by: K2-K6 on October 27, 2021, 06:38:41 PM
If it was switched it will be 180 degrees out and you may get a "phut" or phut-all  ;D if the ignition will fire any mixture with the pistons at the bottom and some valves open.

Something else must be wrong if it's running at all.
Title: Re: 71 advance/retard mechanism
Post by: Nurse Julie on October 27, 2021, 06:56:58 PM
Just so happens Graham has both that I can photograph

Early type, correct orientation

[attachimg=1]

Later type, correct orientation

[attachimg=2]

The earlier type doesn't suit electronic ignition.

Title: Re: 71 advance/retard mechanism
Post by: Bryanj on October 27, 2021, 07:31:38 PM
If it runs like a dog recheck the points gap(14 thou) and timing
Title: Re: 71 advance/retard mechanism
Post by: Popstar on October 27, 2021, 07:39:41 PM
Thanks mine is clearly out in comparison to the one pictured.
Title: Re: 71 advance/retard mechanism
Post by: K2-K6 on October 27, 2021, 07:50:59 PM
Thanks mine is clearly out in comparison to the one pictured.

Also check the wires to the coils for colour as someone may have swapped those to correct an assembly error already (if the cam is in the opposite position, then swapping the wires flips the coils back correctly) meaning it could have two errors there already but will still run.
Title: Re: 71 advance/retard mechanism
Post by: Sesman on October 27, 2021, 08:52:47 PM
 :o :o :o :o
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