Finding top dead center of 83 GS450

[jlineberry]

Hi,

I am working to rebuild my 83 GS450 engine and am slightly confused about the timing. When I first re-assembled the engine, something was off, so I wanted to double check everything. I pulled the cylinder head off again and was checking top dead center. However, when the right cylinder is at the top, the R T timing mark on the flywheel is not lined up.

Should I time the engine based on where the cylinder is or the timing mark?

Thanks for any and all advice!

 

[sawyer]

I had the same problem with my 400 I just used screw driver and found tdc by piston location and was good to go. Bike runs fine.

 

[Nessism]

It makes no sense that the marks would be off unless someone changed the parts.

 

[jlineberry]

I thought it was weird as well, since the bike is stock (as far as I'm aware).

But, with the R T mark lined up, the cylinders are both sitting about halfway in the case. When I place the right cylinder at TDC, the flywheel marks are about 90 degrees off.

I just wanted to check which I should base my timing off of: The mark or with the right at TDC.

Thanks everyone for the responses and input.

 

[Nessism]

The advance unit has various marks on it. You may want to remove the signal generator plate so you can really see what's going on with the various marks on the advance unit. My guess is you are looking at the wrong marks.

 

[jlineberry]

Here's what I'm looking at with the right cylinder TDC. The mark I'm using is in the top left just by the screw. I intend to install a new ignition system regardless, so I'll just time the engine off of what I'm seeing with the cylinders in the case and the right at TDC.

 

[Nessism]

Something weird going on. I haven't messed with a 450 in a long time but I don't see the timing marks in your photo.

 

[Gorminrider]

yes indeed missing bits? "Finding TDC" bwringer is here-might help

http://www.bwringer.com/gs/tdc.html