Top Dead Centre.

[jfheath]

Removed

 

[wjbertrand]

If the cams are out it sort of doesn't matter yet. Whether at TDC it is on compression or exhaust stroke will depend on the cam shaft positions when you replace them. The STs (1100 and 1300) both fire a waste spark on the exhaust stroke.

 

[wjbertrand]

Since posting, I had a look at the wiring and followed the low tension leads on the circuit diagram. Decided it had to be a 'spare spark' set up. Nothing else made sense really.

Thanks for the prompt confirmation. I can stop worrying about it now.

I finally got down to the right hand cam chain tensioner with home made tool, probing between the rubber guard, throttle cables and rubber tubes.

Got the bolt out without any problems, but I wonder how many aluminium washers are floating around in the Vs of ST1300 engines around the world.

Sounds like there is a story here?

 

[GitSum]

The easiest way I found to tell that #1 is TDC on the compression stroke is to look at the lobe on the #1 exhaust cam. It should look like this

Here is a thread with some more info and a worksheet

https://www.st-owners.com/forums/showthread.php?t=72139&highlight=valve+worksheet

 

[hojo in sc]

The easiest way I found to tell that #1 is TDC on the compression stroke is to look at the lobe on the #1 exhaust cam. It should look like this

Here is a thread with some more info and a worksheet

https://www.st-owners.com/forums/showthread.php?t=72139&highlight=valve+worksheet

+1 and look at the photos of the service manual, it takes a magnifying glass to see, but they show RI and RE for intake and exhaust, you look at the appropriate side cylinder (the photos show which cylinder to look at; right or left). Then inside the cylinder you can see the RI and RE markings as to where they should be during the compression cycle.

 

[wjbertrand]

The easiest way I found to tell that #1 is TDC on the compression stroke is to look at the lobe on the #1 exhaust cam. It should look like this

Here is a thread with some more info and a worksheet

https://www.st-owners.com/forums/showthread.php?t=72139&highlight=valve+worksheet

But, but, but he said the cams were already out.

 

[GitSum]

Well, I think it goes back to what wjbertrand said in post #2 - If the engine is brought to TDC using the T1 mark on the CKP sensor rotor, the way the cams are installed will define whether its TDC on the compression or exhaust stroke.

The only thing I am unsure about is the timing using that method.

The manual indicates to check the timing, you connect a timing light to the #1 spark plug. Then you look for "the index mark on the right crankcase cover to align between the "F" marks on the CKP Sensor rotor.

I have never checked my timing, but I think it is safe to say that the #1 plug should be firing when the F on the sensor rotor is visible. The F is actually on the rotor, not on the tooth, and is slightly before the T1 mark

Since the plug should fire somewhere near the top of the compression stroke, I would think if you are manually rotating the crank, this F mark should be visible and be aligned slightly before the T1 mark...