Topic: Timing cam on CB550 - need clarification (done and done)

[mikethejeepguy]

Bike: 1976 CB550F

So I pieced the motor together at 2am after tripple checking everything according to the manual and after starting it, it ran like %##. Now I wonder if after all my reading and tripple checking I have my cam 180 degrees out of phase. Reading through posts on here and the manual, I seem to be getting conflicting information.

Here is what I did...  Facing the bike from the right hand side (rear wheel to my left, front to the right)
As per the manual: Cyl. 1 & 4 at TDC (leftmost mark above the T F) and the notch on the cam (on the right side of motor ) parallel with the head surface (pointing to the front wheel a.k.a. 3 o'clock) as per this picture...



In this image, I assume the bike's front wheel to be to the right of the image (3 o'clock).

Now reading some posts on here...  people talk about aligning the notch to 9 o'clock. Wouldn't that be toward the back wheel?

"cyls 1-4 at TDC, slot in the cam pointing at the 9th hour exactly"  (turboguzzi).
http://forums.sohc4.net/index.php?topic=55506.msg597519#msg597519

"Slide the sprocket on next, then set the shaft into its bearings.  Set the crank at TDC, the shaft notch at 9:00." (OldSchool_IsCool)
http://forums.sohc4.net/index.php?topic=55506.msg597766#msg597766

"There is a notch on the cam shaft (which should be on the right of the engine) which will line up with the engine casing at the rear at the front." (Sporkfly)
http://forums.sohc4.net/index.php?topic=48290.msg508233#msg508233

The manual I am working with is the CB500 Honda Service manual, with the CB550 supplement. Are the cam settings different for CB500 vs CB550? Please help I don't want to screw anything up. I just need clarification to which way to point the cam notch... back or front wheel?  

[buffalogt750]

You and the illustration are correct. With cylinder 1 at tdc notch in cam should point toward front of bike (which to me also seems like 3 o'clock. I don't know where 9 o'clock comes from. Maybe you can also set the cam at 9 o'clock since cam turns half of crank speed and ignition fires every time piston comes up whether it is a compression stroke or not) Recheck it and make sure you are not a tooth off on the sprocket.

[mikethejeepguy]

Thanks buffalogt750.... am gonna go recheck it all. The motor turns smoothly when I turn the crank with a wrench, but running was a different story. Maybe I missed something. Argh... enough wrenching, I just wanna ride.

[bryanj]

Dont matter a stuff wether the notch points forwards or backwards as long as the crank is on T mark for 1 and 4.

Cam turns at half engine speed so on alternate 1 and 4 T marks it will be front or back

[mikethejeepguy]

Guys, I just wanted to say thanks for your advice and replies. After pulling 3 days of wrenching till 3am (some time spent polishing) I finally hit the wall yesterday. What happened last night is that the bike started and ran for a little bit, but there was a screeching grinding noise coming from the crank area. So I double checked all my work today, timing, valve clearences, started her up... same screech.  I felt the stator (which I had removed a few days ago) and it was crazy hot after running for only a few seconds. Needless to say, I noticed metal flakes on the rotor. Apparently the stator didn't seat properly and was grinding. After that... the bike fired right up and ran better than ever. No more cam chain noise! I also put the original pipe back on and can't believe how smooth and quiet the bike is.

The only thing is that if feels flat on acceleration. I did notice that when I have the plugs out, and check the spark, it is a pretty feeble spark. I also noticed that I have DR7EA plugs that I was given by the parts store. I guess I should change them to D7EAs. I wonder if new coils would help too? Am hoping to use ones off an early 80s Honda CB900C...

[OldSchool_IsCool]

+1 what BrianJ said.  Notch at 3:00 or 9:00 makes no difference since the cam will rotate 180 degrees as the crank rotates 360.

Glad you found the bound up rotor before any significant damage!

Weak spark?  Check all the connectors.  The black/white wire is 12v supply from the kill switch.  The blue and the yellow wires provide a path to ground via the points and condenser.  If there is any corroded or loose connection in any of those wires (suspect black/white since your spark is weak on all four) then current will be reduced which reduces the magnetic field of the coils which reduces output.  Check also the connection between the plug caps and the plug wires.  If there is any green in there, then nip off about a quarter inch from the plug wire to expose clean copper.  Check the resistance of the caps while you're at it.  Should be 5000 ohms (or is it 10,000?).  Since you have resester caps, you don't need resister plugs.  Go with the D7EA's.

If you want to boost your coil output and make it less sensitive to points pitting, consider a Hondaman Ignition Module.  It's basically a solid state switch that take the points pulse and switch the coils on and off.  Instead of the points carrying the full current of the coil, the points get only a small fraction meaning they don't erode as fast.  That means you won't be messing with them much, maybe one a year. 

[mikethejeepguy]

Hey OldSchol,

Thanks for your reply. I gotta say that reading 9:00 when I installed the cam at 3:00 kinda freaked me out as a newb and hearing stories of valves hitting the piston Especially when I heard grinding... I was sure I buggered something with the cam chain. Man does it ever run nice n quiet now with the new tensioner. The chain was noisy from the time I bought the bike so I had no comparison.

I'll be going over the coils connections this week and am off to the dealer for D7EAs (since no one else around here has them). All parts places have DR7EAs for some reason. I hope that helps. I cleaned and greased all electric connections this spring, but maybe neglected to do that on the coils. Oh... I unfortunately ordered a Dyna S before I read the post on Hondaman's ignitions but am hoping to build up my spare motor over the winter and drop it into a custom cafe next year, and that one will run H-man's ignition for sure. Gotta support our fellow SOHC gurus!

Once again, thanks to all for taking the time to reply to my long winded posts and helping me along.  I hope to go for a ride this afternoon on a now much quieter bike... cam chain AND exhaust. TT would be proud... back to stock.

Now onto the next issues... changing the jets and needles in my carbs back to stock... and addressing my spark issue. I'll get it running right yet!