TDC

[Urban Surfer]

I'm doing my first valve adjustment. I set up the left side, everything went easier than I expected. The other side I can't seem to get top dead center, so the valves are loose. I am using the method of turning the engine over with a socket wrench on the pulley at the front of the engine, and watching for the OT mark to line up. Turned it over a few times but can't get the valves loose at that point.

What could I be doing wrong?

[Tobias]

The TDC mark isn't important.

What is important is that the cam followers are on the base circle of the cam and not rising up on the lobes.

[SKYGZR]

If you're unsure, remove the spark plug (should have done that anyway), insert a long blade screw driver into the bore, rotate the crank (clockwise) while "feeling" the movement of the piston travel while you turn the crank bolt. You'll be able to tell when the piston's at TDC (or close to). (try not rotate the crank counter clockwise while feeling for TDC)..just keep rotating clockwise while feeling for TDC.

 

A few tries, you'll get a feel for when the piston's gonna be there. (it will be 360^/ full rotation for TDC on the compression stroke.)

 

Once there, the tappets should be "loose", and be able to be wiggled to confirm. Adjust as required.

 

 

[eddd]

I always use the a chopstick in the spark plug hole. I find it a very easy technique which does not require you to find one small mark, you just need to be close.

 

Like SKYGZR said, once you can wiggle the now loose tappets you are close enough.

 

If the exhaust tappets are tight when the piston is at the top of the cylinder you are at the top of the exhaust stroke. Keep going and the next time the piston is at the top, your valve will both be closed ready for adjustment.

[Selden]

I use a variation of the chopstick method, with a wood dowel that is slightly smaller in diameter than the spark plug hole, with a piece of blue masking tape marking the position corresponding to TDC.

[terryofperry]

Urban Surfer

 

I have come across a set on an R850R that was like that. The valves on one side were tight in any position. Turns out they were tight. I turn the crank the same as you and look at TDC the same. Never taken a spark plug out, but that is just me. Between the TDC mark and the arrow on the cam gear you should be confident where you are.

 

Keep us up to date.

 

Terry

[Urban Surfer]

Ok I got. The valves are tight, I can just barely move them, but they all move so I should be in the right position to adjust them.

Thanks.

Now on to balancing the throttle bodies

[Eckhard Grohe]

Before you take out the spark plugs, remove the plug cap and give a good blast of air down there. It is open to the elements near where the plug seats and crud can accumulate there.

 

Eckhard

[rich t]

My cam sprockets have alignment marks that seem to correspond to the intake and exhaust tdc. The marks face toward the back of the bike. The chopstick method didn't work as well for me.

[AndyS]

Ok I got. The valves are tight, I can just barely move them, but they all move so I should be in the right position to adjust them.

Thanks.

Now on to balancing the throttle bodies

 

Are you sure you have it right?

When the OT timing mark is showing, only one side should be loose, the other side should be tight. Then after rotating the engine a further 360 degrees, the other cylinder should be loose, and its opposite number tight.

The inlet rocker gap should be 0.006 of an inch. (0.15mm)

The exhaust rocker gap should be 0.012 of an inch (0.30mm)

 

Andy