Topic: HOW TO START ENGINE

[revjim]

I have a 74 sohc and I want to start the engine, but I don't have the bike together.  How do you guys test your engine with the bare minimal setup.  Thanks.

[BobbyR]

Is it mounted in the frame?

[revjim]

it is mounted to frame...that is it!

[754]

Tie it down, hook up oil tank & lines, Battery and coils..put poer to the coils(use a switch).. then kick or crank away.

[mystic_1]

You'll need gas, electric, oil, and exhaust.


I have a Motion Pro fuel canister that hangs on the wall and holds around a liter of gas.  You can also hook up a long line from your tank or just drop the tank back onto the frame.

Mount the exhaust - running an engine with no pipes at all can result in burning up the exhaust valves.

Electric is the biggest hassle if you've already removed it all.  If you have spare parts lying around you could whip up a test panels with all the required parts (reg/rect, starter relay, switches etc) on a board and some long leads to plug into the engine, but unless you're going to be doing this more than once this may be more trouble than it's worth.

I've seen guys who made test-rigs like this that run the bikes on an engine stand.  There are some pics on the Cyclex website that come to mind.

hth

mystic_1

[Bodi]

If you want a quick and dirty test of whether the engine will run, you don't need much time or money invested.
You can start it with open exhaust ports, don't run it for a long time like that though. It will sound incredibly weird... don't worry about that either - with pipes it will sound normal.
You need the oil tank with a dry sump (750) motor. Watch out if it's sat a long time, you may now have a full sump and empty tank if the check valve leaks... if you fill the tank you'll get an oil gusher from the tank when it pumps the sump out. I would remove the drain plug and check that personally.
Fuel is required obviously. I soldered a plumbing petcock (probably for a heating radiator air vent, I dunno... Home Depot) in the bottom of an old metal syrup can and a wire hook to the top: with a pint of gas in it I can hang it on a nail beside & above the bike.
Electricity is very simple for kickstarting: 12V battery, "-" terminal to the frame, "+" terminal to the ignition coil black wires. You should have a switch of some sort in the + wire. For electric start it's a bit more complicated to do a "nice job" but in a pinch I have just used a (separate) car battery and jumper cables... connect the black "-" cable to frame and when you clip the red "+" wire to the starter motor wire or the solenoid terminal (if attached) the starter motor will run.
If it has linked carbs you can manually rotate the cable wheel to open the throttles, if it's a really old one with four throttle cables you will need at least the cables and 4-1 splitter to get any useful throttle action (pull on the cable end...).

[kta]

If you just want to see if the thing will start for a few seconds just squirt gas directly into the intakes and give it a couple kicks. No need for the exhaust, carbs, oil tank, etc. Just don't run it more than a few seconds.

[Tim.]

It would seem to me that if you've rebuilt the engine, checked compression, valve clearances etc. and torqued everything down, you might as well put it in the frame.  Any further work to make it run well (timing, carb balancing etc.) can and should be done in-frame unless you have a really solid setup like the others mentioned.