Which timing plate for 550/650 swap?

[Guest]

Ok, So when I went to put the mechanical advance onto the engine I'm currently rebuilding, I noticed that the donor 550 did not have the timing plate that sits behind the pickup rotor. My original 550 didn't have one either so now I gotta get one. The question however, is which one? The 550 or the 650? Note that this is a 550 lower end with a 650 top end.

I have included a pic of the two pickup units. The one attached to the motor in the pic is the unit from a 650 and the one to the left is the original 550 unit. As you can see, the TDC and reference marks are quite different between the two.



Anybody got any idea on this? BTW, I do plan to degree the cams so maybe it doesn't even matter?

Thanks.

[SqDancerLynn1]

I would use the one from the 550 bottom end

[Guest]

Bumping. Still looking for some input on this.

For those who have done this swap, which did you use and why?

Thanks.

[Suzuki_Don]

Clay it doesn't matter which plate you use behind the advance/retard unit. It is only there to give you reference mark/line to accomplish your timing and it is a reference mark for other tasks as well.

[Guest]

Um, I'm not sure I follow Don. What am I missing? Would degreeing the cams create new marks so I won't really need these or ?

Thanks again for your patience.

[Suzuki_Don]

Clay there is a thin tin plate in front of the advance/retard units on these motors, it is held in place by 3 screws. This plate is stationary. On that plate there is a single vertical line stamped which aligns with the "T" mark on the advance/retard unit when the motor is at TDC. You need this plate. And you need to use the GS650 advance/retard unit for this swap.












Hope this helps.


P.S. When you get the degree mounted and have the motor at TDC on N0. 1 cylinder check that the reference mark on the plate is correct and adjust if necessary.

[Guest]

Ok well I don't have that plate. Figures. I guess I will have to make my own and setup my own reference marks then. I am using the 650 unit.

[Suzuki_Don]

Ok well I don't have that plate. Figures. I guess I will have to make my own and setup my own reference marks then. I am using the 650 unit.

Clay that plate only costs $8 from a dealer. Not worth the trouble making one yourself.