Yamaha XS500 timing question

[kawasaki kdx]

I have yet another question on how to set timing(I look at Yamaha TX500 service manual)! I don't see any marks on this and it says remove hex plug? on left side to turn engine to align marks!

 

[kawasaki kdx]

I have yet another question on how to set timing(I look at Yamaha TX500 service manual)! I don't see any marks on this and it says remove hex plug? on left side to turn engine to align marks!

I have spark, both plugs spark at same time when I kick over!

 

[MacMcMacmac]

Both plugs will fire every stroke in a wasted spark system. This allows for the use of one set of points or electric trigger to run both cylinders.

 

[Its been a long time]

Both plugs will fire every stroke in a wasted spark system. This allows for the use of one set of points or electric trigger to run both cylinders.

Hmmm. Picture above clearly shows two sets of points though?

 

[MacMcMacmac]

Well I guess I'm full of it then. Lol. Carry on! I'm too used to dealing with our 360deg twins I guess.

Second thought, maybe someone put a dual fire coil on?

 

[jetmechmarty]

Hmmm. Picture above clearly shows two sets of points though?

I believe the XS500 has a 180 degree crank. Therefore, two sets of points would be required.

 

[Its been a long time]

I believe the XS500 has a 180 degree crank. Therefore, two sets of points would be required.

I see. Makes perfect sense then, I agree.

 

[Jim]

I believe the XS500 has a 180 degree crank. Therefore, two sets of points would be required.

Correct.

 

[Its been a long time]

OK. With a 180 degree crank and two sets of points, plug will fire each upward stroke on each cylinder. But left and right sparks should be 180 degree carnk rotation apart each time there's a spark. If left and right plugs are genuinely firing together, then there is an issue.

 

[Its been a long time]

I have spark, both plugs spark at same time when I kick over!

Are you absolutely sure? The sparks left and right should be 180 degrees of crank rotation apart. You can see the two sets of points are 180 degrees apart in the picture.

 

[jetmechmarty]

Will fire each upward stroke on each

No. Every other TDC event.

 

[Its been a long time]

No. Every other TDC event.

Not on a system with two sets of crankshaft triggered points. Each and every stroke towards TDC on each cylinder (like a two stroke engine). Hence, known as a wasted spark system on a four stroke engine.

 

[jetmechmarty]

Not on a system with two sets of crankshaft triggered points. Each and every stroke towards TDC on each cylinder (like a two stroke engine). Hence, known as a wasted spark system on a four stroke engine.

I assumed cam triggered. I should not assume.

 

[Jim]

Not on a system with two sets of crankshaft triggered points. Each and every stroke towards TDC on each cylinder (like a two stroke engine). Hence, known as a wasted spark system on a four stroke engine.

It's not driven directly from the crank. there's a shaft and gear that reduces it to 2 to 1.... so it's timed just like a camshaft driven system.

 

[jetmechmarty]

It's not driven directly from the crank. there's a shaft and gear that reduces it to 2 to 1.... so it's timed just like a camshaft driven system.


View attachment 259900

Thanks for vindicating me!

 

[Its been a long time]

It's not driven directly from the crank. there's a shaft and gear that reduces it to 2 to 1.... so it's timed just like a camshaft driven system.


View attachment 259900

Thanks for that. I would never have guessed looking at the picture posted above.

Looking very carefully, I see the points are handed and the heels are 90 degrees apart. OP can forget what I thought above.

But, if the plugs fire together, there's definitely a problem there.

 

[Its been a long time]

Thanks for vindicating me!

Yes, you're right.

 

[MacMcMacmac]

Fairly elaborate system. I guess they were trying to extend the life of the points on a 10k rpm motor.