ignition timing adjustment

[KNS]

i am putting my 1975 R90s back on the road and am having starting issues. If the choke is open or the throttle is opened the engine does not want to crank over and the battery is new and fully charged. Is this a result of the timing being to advanced? Also the plate that the points attaches to does not have any slots in it for advancing or retarding the timing. I am at a bit of a loss and would appreciate some friendly advice.

Thanks
Ken

[Ken in Oklahoma]

i am putting my 1975 R90s back on the road and am having starting issues. If the choke is open or the throttle is opened the engine does not want to crank over and the battery is new and fully charged. Is this a result of the timing being to advanced? Also the plate that the points attaches to does not have any slots in it for advancing or retarding the timing. I am at a bit of a loss and would appreciate some friendly advice.

Thanks
Ken

Ken, I'm having trouble imagining any way that the choke (enricher) or throttle could affect the engine cranking. There's no functional connection between the carbs and the starting system.

Let me ask the question. If the choke is closed and the throttle is closed, does the engine really turn over then?

Also whether the timing is retarded or advanced the engine should turn over or at least it should attempt to spin the engine. When the engine fails to crank, does anything at all happen? For example do you hear a slight clicking of the starter relay or a not so slight sound of the starter solenoid clicking or thumping? Or is there dead silence?

I would be concerned about the battery cables and connections. The negative side is easy to get at since the negative post is connected to the transmission. On the positive side the battery connection is out in the open so it can be examined. The othe end of the cable goes into the engine top cover and it would have to be removed to get at the battery connection at the solenoid.

You could also try jump cables from your car to your battery. The voltage is the same so the car battery won't hurt your electricals.


Ken

[Major Softie]

KNS, it sounds like we are having a vocabulary issue with you. To us, if the motor isn't "cranking," that means the starter is not turning the engine, while "firing" would refer to actual combustion taking place when starting. Do you mean that the starter will not turn the motor with the throttle open, or that the starter turns the engine but the engine will not start running?

[ME 109]

Nothing like a little air/fuel mixture to stop a piston dead in its tracks if the timing is way advanced.

[KNS]

Thank you for confirming my suspicions ME 109. My apologies if I did not describe the problem clearly. What happens is when I turn the key with either the choke on or the throttle slightly opened the engine does not turn over in a normal fashion, it will turn over then struggle to keep turning over, however it will start and run very well if not a bit rich. I think what might have happened is that when I put the engine back together I put the flywheel on not in the original position ....
Thanks to all I am taking the trans out this weekend and repositioning the flywheel properly.
Ken

[ME 109]

I think what might have happened is that when I put the engine back together I put the flywheel on not in the original position ....

That'd do it.

[Duane Ausherman]

Before you pull the transmission, prove that the flywheel is on in the wrong position.

If there is any error in the battery, wiring or starter motor, you may well find that it can crank at uneven speeds. That would depend upon how much fuel gets into the conbustion chamber and when it fires. I suggest that you question every assumption and check over everything.

You could start with putting the engine at TDC, or a bit early and then checking for the points opening at that time.

[KNS]

Thank you Duane I will verify the flywheel position and the electrical before removing the transmission. The project has taken so long that I may have thought I had the cylinders set at TDC before reassembly but I did not check. A bad assumption.
Thanks again
Ken

[ME 109]

Of course, now we must question whether you blocked the crank when you had the flywheel off?

A critical step to take when the flywheel is removed to prevent the crankshaft from moving forward, and taking a thrust washer with it.......