The spark plug gap in a Yamaha Seca is 1/2. It can be easily obtained and is very affordable and likely to be replaced by the owner. It is a quick replacement.
the difference is the Yamaha is better
0.031 to 0.035"
The proper spark plug gap for a 1997 Yamaha YZF600 should be .028 inches. The best spark plugs to use in a YZF600 are copper.
part #: NGKDPR8EA-9
.028-.030
.030-.040
There is NO WAY a stock Seca 2 will do 140. About 115-120, which isn't bad.
NGK D8EA/DR8EA/DR8EIX or equivalents.
The spark plug gap, on your 1994 Honda, is .013. Most spark plugs will come pre-gapped from the spark plug manufacturer.
The drain plug is on the frame, just behind the front wheel.
I am not sure what to do if your Grizzly 600 Yamaha will not start. You can try taking it to a shop and having it worked on.
Just a wild guess, but I would start at the top of the heads.......should see a spark plug wire connected to a plug........viola! spark plug.