Topic: Cb550 Cam Install Question

[Wreckitralph54]

So I have a cb550 and the top end was taken apart. I set the timing mark on the crank to 1-4 TDC. I then installed the cam with the notch aligned parallel to the mating surface of the valve cover. I then finished assembling the motor and getting it prepared to fire. The motor kept back firing out of the exhaust on cylinder 4 and out the carb on cylinder 1. I swapped the blue and yellow wires coming from the points and the bike fires up.
Obviously I aligned the cam on the wrong stroke so do I just have to rotate the cam 180 degrees to correct the issue?

[That 70s Bike]

No, it's correct.
Cam notch horizontal at either 3 or 9 o'clock determines the TDC compression or TDC exhaust stroke for cyls 1 & 4. (valve timing)
Apparently something's going on with the (ignition timing) points wiring as you've found.

Edit: just checked the 550 manual, the blue wire is for points 1-4 and yellow for points 2-3.
So were they on the wrong point sets?

[BomberMann650]

Pictures help a lot in this situation

[goldarrow]

Check that the ignition cam at the points plate is installed correctly.  With the crank turn to 1-4 T, the tiny little dot on points cam should point to about 4 o'clock position.

Points advance cam

[jonda500]

Check that the ignition cam at the points plate is installed correctly.  With the crank turn to 1-4 T, the tiny little dot on points cam should point to about 4 o'clock position.

Points advance cam

+1 it's not the cam alignment it's the points cam like goldarrow says - you have the points cam installed 180 degrees out.
John

[Wreckitralph54]

Thanks guys it's deffinantly going to be the points cam. I'll check it on Sunday when I get back home!

[Wreckitralph54]

Is the points cam removable?

[BomberMann650]

Yes, remove the little bolt in the center of the big nut attached to the crank.  Remove the points plate, then the advancing unit comes out. 

[calj737]

As long as you have swapped the ignition wires to the correct coil as oriented to the points cam, you needn't change anything further. Your bike will be fine just as it is from now on.

[strynboen]

think too,,its the ignision cam vho are turned a half rotation vrong.
.its a 100%  for mee..have done it 4 times now..its just pulls aut..and can be mounted vrong vhen you lube it..and thek the springs for tension

[jonda500]

As long as you have swapped the ignition wires to the correct coil as oriented to the points cam, you needn't change anything further. Your bike will be fine just as it is from now on.

True! I ran my 400-4 for many years with the blue/yellow wires swapped after installing the points cam 180 out.
John

[That 70s Bike]

As long as you have swapped the ignition wires to the correct coil as oriented to the points cam, you needn't change anything further. Your bike will be fine just as it is from now on.

True! I ran my 400-4 for many years with the blue/yellow wires swapped after installing the points cam 180 out.
John

If you never correct it and decide to sell it, at least tell the buyer the points cam & wires are reversed or he could be back here posting about the wire colors conflicting with the manual info.