ahhh back fire

[C.N.]

While attempting to set the points on my cb77 for the first time we discovered that the entire assembly was in upside down. After turning it 180 degrees and reassembling it the bike back fires shooting flames out of pipes. Did I set points incorrectly? Did the wiring get crossed somewhere in time? What the h*#l?
C.N.

[LOUD MOUSE]

At the coils and points GREEN RIGHT/YELLOW LEFT per wireing diagram in the HONDA BOOK. .................lm

While attempting to set the points on my cb77 for the first time we discovered that the entire assembly was in upside down. After turning it 180 degrees and reassembling it the bike back fires shooting flames out of pipes. Did I set points incorrectly? Did the wiring get crossed somewhere in time? What the h*#l?
C.N.

[cknight]

There is also the possibility that during a previous rebuild, the point cam was incorrectly installed 180 degrees out into the cam drive sprocket assembly. The point plate assembly would then have accordingly been rotated "upside down" to get the proper relationship to the cam restored. Check Top Dead Center firing on each cylinder (both valves completely closed) to make sure that the points for that cylinder are just opening. Regards, Chase

[LOUD MOUSE]

Chase has a good idea there. I recommend you remove both right side tappet covers, points cover and rotor cover. Index rotor to "T" and see if both tappets are loose. If only one is loose turn engine 180 degrees and check tappets again. When both tappets are loose the line/mark on the end of the points shaft should be pointing DOWN THE CENTER of the cylinders. "Line will be on the bottom of the points shaft". If it's at any other location the cams and timing are not correct. ................lm

There is also the possibility that during a previous rebuild, the point cam was incorrectly installed 180 degrees out into the cam drive sprocket assembly. The point plate assembly would then have accordingly been rotated "upside down" to get the proper relationship to the cam restored. Check Top Dead Center firing on each cylinder (both valves completely closed) to make sure that the points for that cylinder are just opening. Regards, Chase

[C.N.]

You guys are awesome. I couldn't do this without this forum and especially help from you guys. Thanks lm and cknight I really appreciate your expertise!
C.N.

[C.N.]

Ah maybe that's it. The previous owner mentioned having the top end redone. How difficult is it to reinstall the points cam correctly?
Thanks
C.N.

[LOUD MOUSE]

I would hope you have made sure the points cam is 180 degrees out. Remove the engine. Remove the top and the points end cover and loosen the large nut on the sprocket and remove the 2 cam followers on the right side.
Drive the right sprocket out enough to be able to turn the cam sprocket 180 degrees. So the line on the end of the points cam is in alignment with the dot/circle on the sprocket. Slowly drive the cam back into the head being sure the points cam is fitting into the sprocket correctly. (moves but doesn't turn). ............lm

Ah maybe that's it. The previous owner mentioned having the top end redone. How difficult is it to reinstall the points cam correctly?
Thanks
C.N.