I am thinking about buying a 12MM TDC tool.

They screw into the #1 spark plug hole and have a rod that screws in and out to touch the top of the piston.



Whats the proper way to use the tool?



Gerry

Puccini wrote:I am thinking about buying a 12MM TDC tool.

They screw into the #1 spark plug hole and have a rod that screws in and out to touch the top of the piston.

Whats the proper way to use the tool?

Gerry

Long time ago I had one made with an old spark plug and a mechanical indicator.
If the purpose of this is to set the ignition,you are better to do a dynamic setting using a timing light.

CF

Thats a TDC Gauge. The tool I'm getting is a TDC Tool. It only has a screw in threaded stud that the piston butts up against to stop it.

I just don't know how I'm supposed to set it up.



Gerry

Puccini wrote:Thats a TDC Gauge. The tool I'm getting is a TDC Tool. It only has a screw in threaded stud that the piston butts up against to stop it.

I just don't know how I'm supposed to set it up.
Gerry

Take an old spark plug, drill it and install a rod that you can lock in the plug. This is the same principle as the indicator but you will be able to lock the piston.

Hi Puccini,
That's more commonly called a piston stop and you need a degree plate fixed to the crankshaft to determine TDC. Once installed, rotate the engine until the piston contacts the stop and note the reading on the degree plate. Now rotate the engine backwards, again until the piston reaches the stop and note that reading. Half the distance between the two readings will be TDC.
Cheers,
Paul.

Can that be used on the K100?

I've never tried to time a K100.

Is there access to the flywheel or someplace to mark?



Gerry

Puccini wrote:Can that be used on the K100?

I've never tried to time a K100.

Is there access to the flywheel or someplace to mark?



Gerry

The only place to attach a degree wheel is at the front where the hall sensors are. You would need to have a special spacer made to adapt it. I have only ever used a dial gauge so I cant help any futher on a spacer for the front.

sidecar paul wrote:Once installed, rotate the engine until the piston contacts the stop and note the reading on the degree plate. Now rotate the engine backwards, again until the piston reaches the stop and note that reading. Half the distance between the two readings will be TDC.
Cheers,
Paul.

Could be that I completely misunderstand something here...
But this must then be carried out at cylinder #2, to find TDC at cylinder #1.
If all carried out at #1 you find BDC.

Inge K.

Inge K. wrote:

sidecar paul wrote:Once installed, rotate the engine until the piston contacts the stop and note the reading on the degree plate. Now rotate the engine backwards, again until the piston reaches the stop and note that reading. Half the distance between the two readings will be TDC.
Cheers,
Paul.

Could be that I completely misunderstand something here...
But this must then be carried out at cylinder #2, to find TDC at cylinder #1.
If all carried out at #1 you find BDC.

Inge K.

Once you have set the degree wheel you take the stop out. and there is TDC

Yes, of course...I`m kind of slow today....did think 180 degree wrong.
So I misunderstood it completely.......

Inge K.

I'm with you on this one Inge.

Using a piston stop is a good thing when putting an engine together.
I used one when assembling my fuel engine on the drag bike. I would put the stop in and turn the engine to the stop and that was a known 10 deg BTDC then I could drop the magneto into its place and move it to the correct place just by using the degree arc on the magneto body then tighten a bolt and all was ready to go.
It helps when you need to change an engine between races.

Yes Rick (Oh how I miss K freak), the one I made for the Vincent has a vent so that it doesn't come up against compression and it stops the piston at 34 degrees BTDC which is the ignition timing point. It makes life so much easier.

This morning the sun was shining so I wheeled my spare engine outside and made an adaptor to fit a degree plate to a K........just in case anyone would wish to do so, here are the details.



13mm bar, 110mm long, turned down to 10mm x 50mm long and threaded M10 x 1mm pitch, (note that this is a fine thread) for about 20mm. Tap the end M6 to attach the disc. Cross drill a hole to use a tommy bar for tightening.





I can't imagine that I will ever use it, but somebody somewhere might find the idea useful.
Paul.

I have often thought of making a hole in the bellhousing and marking the clutch carrier in a few places for TDC, BDC and firing points.
I really dont know why it was not done by the factory, I suppose because then the owners could do more themselves and not pay the dealer to seriously neglect the bike.

Rick G wrote:I suppose because then the owners could do more themselves and not pay the dealer to seriously neglect the bike.

a great tool paul....

not only good for electronic/mechanical timing ..but also good for mapping cam lobes, piston tdc and btc ...etc

i have heard (read ) that there is suposed to be different cam timings on early models (pre 85-86) worded as more agressive ......it would be interesting to see if cam duration , lift .and rotational timing across the different models and years made much difference to the performance of the bike ....of corse an understanding of what kind of rev range we use the most (after all we all have different riding abilities and preferences of comfortable revs )

cheers!...... a great tool

Thinking a bit further down this line, if one had a 12mm tapped bar (1.25 pitch - spark plug thread) with a degree plate fixed on the end, one could use it as a piston stop to find TDC: back off the bar and move the piston to TDC: gently screw the bar back until it just touches the piston: back off the piston, then turn the bar clockwise 69.1 degrees and that will be the static timing point.

The timing point is 0.24mm BTDC, one turn of the screw moves 1.25mm, so we need to move the bar 0.24 divided by 1.25, ie 0.192: converting to degrees we multiply 360 by 0.192 and get 69.12. QED

Well, it could be an option if you don't have a dial gauge.....Or should I get out more?
Paul.

When you start making a minature dial gauge to fit the minature brick (that I have no doubt you have already considered making) we will know it's time to call the rubber truck.

Couldn't you simply make that same bar dilled through and put a longer pin through marked for the various, like TDC and the ignition point? Keep it 'loaded' with your finger on it and see how it moves. Flat end on it so in can't fall through........

It is weekend, let's see

You don't get weekends when you're retired Rene,

Now if BMW quoted the timing point as degrees of crankshaft rotation, the crankshaft timing disc alone would suffice.
Paul.

ReneZ has a great Idea just like the old pencil air gauges measure the pin set the crank seat the plug pin unit and start the timing set up. Thats on the money.