TDC

[Beemerman59]

Is there a "foolproof" way of ensuring the L/H pot is at TDC for when adjusting valve clearances? The R/H pot is easy as there's an easy to view mark on the cam chain however I can't see anything for the L/H side. The manual instructions require the use of a tool that inserts through a blanked off hole on the right side of the engine but does anyone know if this works for both pots? If so, would a simple substitution of the BMW tool (which looks a very simple design) be made by using a screwdriver or similar?

Having adjusted my clearances the R/H pot seems relatively quiet (for a Boxer engine) but the exhaust valves on the L/H side are more noiser and I'm wondering if its possible that it wasn't exactly at TDC when adjusted. When doing them, the inlet valve clearances were spot on, with the exhaust side feeling a little tight but maybe the tappet wasn't fully open?

 

[(RIP) Bin Ridin]

when the r/h pot is at TDC, guess where the l/h pot is?

 

[Nice 'n' Fat]

 

[cookie]

when the r/h pot is at TDC, guess where the l/h pot is?

but that doesn't mean it's at TDC on the compression stroke

stick yer finger in the plug hole and the TDC after you feel pressure is the one you want.

ps. don't take both plugs out or you won't be able to tell

 

[karnevil]

Drop me a pm i will knock you up a tool,for an SAE need to make one for myself

 

[Timolgra]

but that doesn't mean it's at TDC on the compression stroke

stick yer finger in the plug hole and the TDC after you feel pressure is the one you want.

ps. don't take both plugs out or you won't be able to tell

Also the valves won't be moving but will be 'rocking' on the other cylinder

 

[Beemerman59]

Also the valves won't be moving but will be 'rocking' on the other cylinder

That's pretty much how I worked it out at the time. Maybe I'm being too picky with accuracy since the inlet and exhaust valves will be closed together and I would have to get it dramatically wrong for the inlets to be closed and the exhausts partially open. I was using the picture sequences shown on one of the links from here to guage when the left pot is at TDC (on compression) - it just doesn't seem as accurate as when using the timing mark on the R/H side.

I also remember the valve noise being greater after a dealer service than before but that would be on both pots not just the L/H side. Rocker arm end play is at the smaller of the range.

 

[Steptoe]

when the r/h pot is at TDC, guess where the l/h pot is?

Not at TDC on the compresion stroke

Insert a thin screwdriver into the plug hole, turn the engine over by hand so the inlet valves have just closed, and when the screwdriver gets pushed out to it's furthest point is tdc. Repeat for the other side.

You can substitute a straw for the screwdriver.

 

[(RIP) Bin Ridin]

Lads, Lads...
If he can find the mark for tdc on the r/h, 360degrees later, same mark, he has l/h set to adjust.
anyhow, setting using crossover on d'opposite valves does fine.

 

[Deleted account W]

You can substitute a straw for the screwdriver.

I used a chopstick, is this frowned upon?

 

[Beemerman59]

Lads, Lads...
If he can find the mark for tdc on the r/h, 360degrees later, same mark, he has l/h set to adjust.
anyhow, setting using crossover on d'opposite valves does fine.

Well, taking a look at this, either you or this guy is wrong......

http://www.r1200gs.info/howto/valve-adj.html

 

[Beemerman59]

Not at TDC on the compresion stroke

Insert a thin screwdriver into the plug hole, turn the engine over by hand so the inlet valves have just closed, and when the screwdriver gets pushed out to it's furthest point is tdc. Repeat for the other side.

You can substitute a straw for the screwdriver.

Thanks Steptoe.

 

[Timolgra]

I used a chopstick, is this frowned upon?

A mate of mine used a pencil with a rubber on the end to find TDC on his Husaberg, of course if you put it in at 'BDC' it may get wedged and snap on the way up.
His did, and it left the rubber and metal retainer on the piston

 

[Steptoe]

I used a chopstick, is this frowned upon?

I have heard things said about them, but it's all just chinese whispers.

 

[Gizmo]

Well, taking a look at this, either you or this guy is wrong......

http://www.r1200gs.info/howto/valve-adj.html

Perhaps not wrong but a little unclear. 360 degrees of crank rotation is 180 degrees of the camshaft, so that should bring the cylinder you have adjusted to a "rocking" position and the opposite cylinder to TDC on the power stroke and ready for adjustment.

 

[Beemerman59]

Now have it all sussed. The arrow to use on the R/H pot is for the R/H pot only, it doesn't help you at all with the left hand pot. To do the left hand pot, it's OK to use the picture in the above mentioned link but I now have a suitable marked chopstick in the GS toolbox - thanks guys great idea!.

I have the Wurth feeler guages so ended up have all four in the valves and one by one set the clearances using the weight of the allen key to determine the correct tightness. If you do this it's worth wiggling each feeler as you do it due to the angle of the valves, otherwise it can feel tighter than it actually is. When the allen key stops moving under its own weight, tighten up the locknut. I did this for all the valves and the bike now sounds a real peach. Job done.

 

[(RIP) Bin Ridin]

Congratulations! Very satisfying to get it done well.

I do see my error above now, as you point out the cam mark is correct for that side only. Ooops.

What I use is the valve cross-over point on the opposite cylinder.

 

[(RIP) Miff]

Surely on the Boxer engine, it's SIDE dead centre???