Topic: Yoshi 605 with yoshi cam, ignition timing

[Seamus]

I have a 605 conversion on my 500 four with a flowed head, 10.5:1 compression and a Yoshi YH500-521-00 cam.
I understand that the ignition timing should be advanced from standard with this set up. Anyone with experience know what the ignition timing should be set at?
Appreciate any guidance

[Seamus]

Sorry, the cam ref is YH500-121-00 if that makes a difference
thanks

[turboguzzi]

no short answer to this one, a lot will depend on how the combustion chamber looks like with your 605 kit and if there's good squish or not.

if anything, there's a good chance you could RETARD the timing and get better power and cooler running by doing so.

many road race motors (including my 500/4) run just 28-30 degs max advance for best power vs. the 35 deg stock.

the best way to find out is go to a dyno and see what advance gives best power

[Tim2005]

I'm with Turboguzzi on this, dyno testing is the real answer. However, I would add that for the CB400F Yoshi 460 kit & ST1 cam they recommended an extra 5 degrees ignition advance & it seemed to work well. Maybe this extra advance was part of the Yoshi design thinking in those days. 

[pangloss]

I put this yoshi kit into my 500...quite a while ago...(btw...the documentation  is on this site somewhere).....Anyway it says 43 degrees BTDC

I ended up with a timing point about 2mm to the left of the post which supports the springs on the advance retard plate

[Seamus]

Thank you all for the good advice. Appreciate the help.