Topic: Did I set the cam RIGHT?????

[Steve F]

OK, did do this right?  I made a degree wheel and attached it to the crank at the points bolt, and using a piston stop, determined TDC for the #4 cylinder (same as #1).  The specs I have for a stock cam (at .040 lift at the valve) for the CB750 is: intake 5 deg. btc and 35 abc.  Exhaust is 35 deg. bbc and 5 deg. atc.   I put an indicator on #1 intake with zero lash and turned the engine to 5 deg. btc.  Set the cam to .040 on #1 intake at that point and locked it down.   The lines at the end of the cam line up exactly with the cam tower cap split at this point. 
Q: Not sure where the numbers I got for the cam came from, but I have a 750F and was also wondering if they're the same for all 750's, or is the "F" engine different with a stock cam.
Q: Was I supposed to have .040 lift at the 5 deg. btc mark???
Q: The second spec for #1 intake reads 35 deg. abc. and I'm getting 25 deg. abc.  Is that at the .040 point or completely closed.

Oh, BTW, for all you thinking that the tiiming marks on the advancer are good, there is at least 3 degrees backlash on a normal spark advance plate!!!!  I never really thought they were dead-on and this was confirmed when I put the dergee wheel on and actually checked it.  The 4mm drive pin that goes in the hole on the end of the crank is sloppy (at least on both of my 750's).

[MRieck]

 Steve
  You should be at .040 lift and be reading 5 BTDC. You should also be at .040 lift when you read your closing number. Not sure what you mean by "locking it down"...do you mean the adjustable sprocket?. I wouldn't get so hung up on the numbers themselves...I'd be more concerned with the Lobe Center number. 5+25=30. 30+180=210   210/2=105   105LC is a good all around cam #  Think about it. Once you put your valve lash in there the valve isn't going to open/close at the same #'s anyway. Personally I check cam # at running lash...the #'s are different from the timing card but I can see exactly what the cam will be doing under running conditions. Good work on your part. Cam timing isn't that hard but you need some tools and confidence.

[MRieck]

PS....absolutely correct about the timing marks.

[Jerry Rxman Griffin aka MuthaF'er]

The specs you stated are for a F0/F1 cam. The other Ks and Fs are different. This comes from the shop manual. 

[MRieck]

The specs you stated are for a F0/F1 cam. The other Ks and Fs are different. This comes from the shop manual. 

That's a good point. If you have all the numbers for the different cams you should try post it in FAQ. Good info IMO.

[Steve F]

Thanks guys for all your help!  I was hoping that the numbers I had were for the "F" model since the cam was supposed to be a little different than the "K".  Last night I had only an hour to finish it up and get the valves set and the cover back on.  Tonight I'll try to stuff the engine back in the frame and get it back together.  It's riding weather and it's buggin me! 

[Jerry Rxman Griffin aka MuthaF'er]

The specs you stated are for a F0/F1 cam. The other Ks and Fs are different. This comes from the shop manual. 

That's a good point. If you have all the numbers for the different cams you should try post it in FAQ. Good info IMO.

Mike,
I can pull the numbers from the Shop Manual without a problem and will be happy to do so. Do you know/Is there any way to ID a cam once it's removed based on the numbers such as R9 that are found on the cam? If you own a bike since new you can be assured it is the stock cam and can determine its specs. Otherwise you can ID the engine based on the engine serial number to determine what model it is/came from then check it that way UNLESS someone has had the engine apart.
Jerry