Advance unit installation. Am i missing something?

[Johnnyb89x]

Hey there. Im installing finishing up a motor rebuild that I put off for too long. Im to the point where I am installing the advance rod and advance unit. My issue is with the assembly on the advance side. Im having trouble finding a good schematic for the parts and assembly. I have put it all together and spun the engine over, but when I do, the lock nut (advance lock nut) loosens up. Im not sure if there is a locating pin that i am missing or if i am not installing everything right. I dont want to run into the issue of things coming apart while im riding...Ive searched on the interwebs for the past couple of days with no luck...any help would be greatly appreciated since this bike will be my only means of transportation and kinda need it finished up yesterday hahaha.

 

[Johnnyb89x]

I forgot to include that I have a 73 TX650. sorry no pictures at the moment. When all was said and done i ended up with a spare pin after using one on the advance side for the notched plate.

 

[5twins]

There are 3 pins used in the advance and advance rod assembly. One pin locates the advance unit correctly on the cam. The other two are used to align the point cam and the little advance disc on the ends of the advance rod.

Mounting the advance unit is pretty much a no brainer. It can only fit on and lock on the pin in the cam in one position. There is a slot on the back of the unit that fits on the pin .....

Put some anti-seize on the cam stub before sliding the advance unit on so the two don't rust together. The notched ring that holds the advance unit on has a raised lip around its I.D. on one side. Face that out.

There's a "gotcha" associated with assembling the advance rod. It can be done incorrectly. The locating pins for the point cam and the advance disc need to point in the same direction or the timing will be off .....

It's possible to assemble the rod with the pins pointing opposite to one another. That will throw the timing 180° off.

Later advance units have a line scribed on the little disc and on the main backing plate (yellow arrows). These should align, or very nearly align. If you're 180° off, the line on the little disc will be pointing in the opposite direction. Your older unit may not have the scribed lines and may have had paint dots instead. No matter, just make sure the advance rod pins (green arrow) point in the same direction and you will be fine.

 

[Johnnyb89x]

I found another thread that showed the pin i forgot to install on the actual camshaft. It was the left over pin. Thank you for the input! and this will give me a chance to make sure the pins on the advance rod are on the same plane.

 

[5twins]

The pin slot in the little advance disc is usually pretty easy to see, as shown above. The pin slot in the points cam or a Pamco rotor, however, is often covered by the nut and lock washer. I mark them with a Sharpie .....

 

[Johnnyb89x]

good tip. So the pin in the camshaft to hold the backing plate is slightly larger in diameter than the pins in the advance rod correct?

 

[5twins]

No, all the same pin, same part #. Part #7 here, 3 required .....

http://www.boats.net/parts/search/Y...AIN TENSIONER XS650D - E - E006501/parts.html