SOHC.co.uk Forums > CB500/550

Ignition Timing and Unleaded

(1/1)

paulbaker1954:
I am assuming that the timing marks on the '71 K0 500 were set for leaded fuel. Does anyone recommend advancing the timing any on these engines to account for the slower burn rate of unleaded vs leaded fuel.

If so any tried and tested level of advance?

florence:
My understanding is that these engines were designed for unleaded fuel in the first place.

Chris400F:
Here's a page from what purports to be the Owner's Manual for a 1972 CB500.
Don't know if it helps or not ....
Normal unleaded nowadays is 95 octane.

deltarider:
Just experiment. Many 500/550s have better driveability with a tad more advance. At full advance I have mine just right of the double F marks. I guess mine has about 33 degrees advance.

florence:
Be very careful though, I know someone who advanced his ignition timing too much and ended up burning a neat little hole in one of his pistons. 

Navigation

[0] Message Index