[Alfalfa]

Hi guys been a while since my last fumbling experience working on my bike but I got a question for yall. So when I try to rotate the generator rotor to find top dead center on what I believe to be the compression stroke (aligning the LT with the index mark) Its like the rotor begins to get a mind of its own. It becomes very difficult to turn and then when I get to just before the LT mark its as if the energy I used to turn the rotor gets released and it spins another 45 degrees all on it's own which causes me to overshoot the mark. After this i can rotate the rotor freely for another full turn but when I try to allign the timimng marks again after a full turn same story. Surely this is not normal... whats going on??


Sorry, bike details:
1975 CB500T

 

[66Sprint]

First, I trust you are rotating it Counterclockwise..... Secondly,the 450 and 500T tend to "want" to overshoot a bit (but usually just a couple or 5 degrees, NOT 45 degrees) Use a box wrench,(not a ratchet) and have a friend hold it in place on the index.....

 

[Alfalfa]

Although usually it is not a good idea to assume I am doing things correctly ha ha, yes I am rotating it counterclockwise. Maybe I overestimated the ammount of jump, but it does certainly push past the timming mark. But i take it this is normal. Is it also normal to have to put a good ammount of torque in trying to get the marks to line up on the compression stroke?

 

[66Sprint]

Yep, the right cylinders ex valve is under pressure (opening) at that time...

 

[jayel]

didn't someone mention using a tapered wooden shim to hold the rotor against the case?

 

[tbpmusic]

didn't someone mention using a tapered wooden shim to hold the rotor against the case?

Yes, that was mentioned.

I just use a very cheap 14mm wrench - a flat one, with no offset.
By putting a longish 6mm bolt/screw into one of the alternator cover holes, I can "trap" the cheap wrench in position and hold the alternator in place really well.
A cheap wrench has more play than a Snap-On or other good wrench.
Noramlly one of the three holes provides the right spot.

 

[Alfalfa]

awesome. great info guys!