Topic: 550F spark advancer - part number confusion

[Fritz]

Hi!

When I took off my spark advancer, I noticed that the dowel pin that goes into the crank shaft is damaged. It's just a loose fit in the advancer - I can actually pull it out. So I decided to replace it fearing that the pin could break at high revs.

I ordered a new advancer using this fiche as a reference:
http://www.cmsnl.com/honda-cb550f1-super-sport-550-four-1976-germany_model17116/partslist/E05.html

Now I'm a little bit confused: The advancer that came with my bike has the numbers "333" embossed into it.
The new advancer has a "323" on it. I also noticed that the "T", "F" and advance marks are at different locations. On the "333" they are "later" than on the "323", meaning that they are nearer to the pins that hold one end of the advancer springs.

This does not make any sense to me. The bike is running great with the "333" advancer, but both CMSNL and the Honda parts list say, that the correct part for my bike is 30220-323-154. If the marks are on different locations, they should also indicate a different timing.

Does anybody know if I can use the "323" advancer on my 550F?

If "323" and "333" indicate the model number, I suppose that my bike has a 350F advancer in it, which is part no 30220-333-004.

This seems to be terrible wrong.

Thanks
Carsten

[bryanj]

The 323 is definately the correct part and you should not use the 333 if the timing marks are in a different place

Edit:-

There is a man on the UK site desperate to get hold of a 400 auto advance unit

http://www.sohc.co.uk/index.php?topic=2721.0

[dave500]

the middle number is the part manufacturer or supplier.323 is honda.,so im told.

[bryanj]

No Dave the middle number is the model of bike the last numbers may designate supplier or suppercission or market type

[Fritz]

The 323 is definately the correct part and you should not use the 333 if the timing marks are in a different place

Thanks Bryan!

What puzzles me is that the bike POs were running the bike with the advancer that had 333 stamped on it and apparently it ran fine.
Whatever, I will try out the new one on the weekend and see how the bike likes it.

Cheers
Carsten

[dave500]

thanks for clearing that bryanj

[Fritz]

No Dave the middle number is the model of bike the last numbers may designate supplier or suppercission or market type

Honda model codes can be looked up here:
http://www.cmsnl.com/faq.php?fq_catid=14
or here:
http://www.groupwracing.com/hondapartnumbers.html

300     CB750.K1
323     CB500-K2
333     CB350FOUR
363     CB40FOUR
374     CB550K1-P
377     CB400.F-F2
390     CB550F.1.2
392     CB750F.1.P
393     CB750AT-A2
404     CB550K3-P3
405     CB750K7-P7
410     CB750F2.F3
425     CB750KZ-CA
426     CB650Z.PZ
445     CB750FZ.FA
460     CB650A.CA

[Fritz]

Well, I changed the "333" advancer with a "323" one and adjusted the timing according to the different marks.

Here's what I found out:

- The bike is idling a little smoother
- It feels like it lost a little power

Doing some measurements, I've got these "hard facts":

323 advancer:
F mark: 6° before TDC
Advance mark 1: 29° before TDC
Advance mark 2: 32° before TDC

333 advancer:
F mark:10° before TDC
Advance mark 1: 33° before TDC
Adance mark 2: 36° before TDC

Cams are the same.

The springs on the "333" advancer are a little bit weaker so the full advance will be at lower RPMs.

So the difference between a 323 advancer and the 333 is that the 333 is 4° ahead and full advance is earlier than the 323. Bike will idle a little bit rougher and feel "crispier" with the early timing.

Here's my question: Will it do any harm (besides rougher idle) if I keep the "333" advancer and run premium gas?

[bryanj]

Shouldn't even need premium gas for that small difference. Its les than the extra Yoshi used to run with pump gas

[754]

750 had 2 types.
 The one you choose may depend on other things you do to the motor and how you ride it.. may be there for a reason..