VAC advance Assembly install question

[79XS11F]

OK .. My hop-up engine is ready to start save and except for confirming the following item.
I took the VAC advance Assembly off the engine that came out of the bike because the pickup coils on that unit are new and gapped correctly. It was a time saving measure.
There are no instructions in ether of my manuals as to what the final position of that assemble is when installing it. How do I know what the exact position for it before tightening the assemble in place.
Rob

[TopCatGr58]

Hey Rob,

The PU coil/vacuum advance assembly is mounted onto the shaft with a slot in the assembly for adjusting as you "try" to set the timing!! So, once you are able to start the screws, just position the assembly in the MIDDLE of the adjusting slot, and then you'll need to start the bike, and use a timing light as per your manual to check and adjust the timing accordingly, unlocking and then rotating the assembly CW or CCW, and then retesting to see if you got the timing on the right position! What fun!
I haven't had the opportunity to do this process on my Basket Case YET, but was wondering?? When I adjusted the timing on my old V-8 firebird, the engine was running, and I was able to turn the distributor while viewing the timing light marks while it was running, and then able to lock it down.

Why can't we do the same with our bikes, unlock the screws just enough to allow the assembly to spin/rotate under modest pressure, fire it up and shoot the light, and then rotate the assembly while running until the light and marks align, and then tighten it down then???? Beats starting, checking, stopping, loosening, adjusting, locking down, and the restarting and rechecking with light, repeating!? I realize that the timing late will be spinning, is it just a safety issue not wanting to catch your fingers on the spinning plate!?!?
T.C.

[79XS11F]

It's likely the safety issue. Something like that sounds like it would be real easy to do with two people. One shotting the gun the other rotating the plate.

So I will do it that way. I want to start stop the engine minimum number of times to do this so I may just do the plate rotating thing with the engine running. On first start up it has been suggested to me that I fire her up, bring her to normal operating temperature, shut her down, let completely cool, and re-torque the head.
Thanks
TC
Rob

[mro]

re-torque the head

Used to allways re-torque heads, then new type gaskets don't need it. Would ask your gasket maker what they suggest. Looked thru Yamaha manual and there's nothing in it about re-torque the head.

can't see it hurting anything tho.............



mro

[79XS11F]

Re: re-torque the head

Originally posted by mro
Used to allways re-torque heads, then new type gaskets don't need it. Would ask your gasket maker what they suggest. Looked thru Yamaha manual and there's nothing in it about re-torque the head.

can't see it hurting anything tho.............



mro

Hmmm . both my manuals call for this procedure under the "tune
up" section with a complete tune up being recommended every 4000 KM.
A mechanic at the local shop also recommended this procedure.
As you say ... right or wrong it won't hurt anything to check them after a rebuild
Rob

[randy]

It's likely the safety issue. Something like that sounds like it would be real easy to do with two people. One shotting the gun the other rotating the plate.

What TC said was basically right, that will work. For safety's sake, what I've done is NOT rotate the plate with my hand, rather I use the butt of a ratchet or whatever is handy to tap on the mounts to rotate the plate. Keep in mind, you don't want it too loose when you do this or the setting will change as you tighten it down. It's a one-person job.

[79XS11F]

ya it can be done alone holding the timing gun in one hand and taping the plate with a tool held in the other hand.
As it turned out the way my coils went back into the bike my #1 cylinder is not readable with my timing light so I will have to check the timing with the pared cylinders plug wire.
Rob