Cam Chain Adjustment

roncieri313 · Posted: Sun Sep 07, 2008 6:14 pm Post subject: Cam Chain Adjustment

Honda Experts...does the cam chain on my CB450 (K6) have to be adjusted in conjunction with the valves so I can be sure the pistons are at TDC?...thanks.

tbpmusic · Posted: Sun Sep 07, 2008 6:18 pm Post subject:

Usually it's done immediately after adjusting the valves, but you can do it anytime.

bill

roncieri313 · Posted: Sun Sep 07, 2008 6:26 pm Post subject:

So, I can do what the manual (from Honda not Clymer's) simply says below and no need for the TDC if I don't have the time right now?...thanks Bill.

Cam Chain Adjustment

A loose cam chain will cause the timing of the valve to change, resulting in poor engine performance. It will cause a drop in power output and also produce excessive noise.

Adjustment is made by loosening the tensioner lock nut (2) and tensioner lock bolt (1) this will cause the tensioner push bar to automatically apply the proper tension to the chain.
After completing the adjustment, tighten the lock nut.
NOTE: Do not apply additional pressure on the tension push bar as this will apply excessive tension to the chain and the guide rollers, shortening their service life.

tbpmusic · Posted: Sun Sep 07, 2008 8:54 pm Post subject:

Honda manual says do it at TDC - they don't specify, but it should be TDC Left Compression stroke.
Here's the page from my honda manual -

Link to PDF Extract

The CB500T manual, which is usually very helpful, has less info than the 450 manual in this case.

bill

Barchetta · Posted: Sun Sep 07, 2008 9:35 pm Post subject:

edit, sorry.

tbpmusic · Posted: Sun Sep 07, 2008 9:38 pm Post subject:

roncieri313 · Posted: Mon Sep 08, 2008 6:17 am Post subject:

Here's what I found in the 450 manual...I understand the alternator part but not the valve markings part..maybe you guys can help make sense of it for me...thanks.

Valve Tappet Adjustment

Excessive valve clearance will cause tappet noise and negative clearance will cause valve damage, excessive wear of the cam follower, and loss of power.

Therefore, the valve tappet clearance should be maintained properly.

Turn the fuel valve to the "STOP" position, remove the fuel lines from the fuel valve body, raise the seat and remove the fuel tank.
Remove the cylinder head cover A (inlet side) and B (exhaust side).
Remove the point cover and the dynamo cover.
Rotate the generator rotor counterclockwise and align the "LT" mark (1) on the generator rotor with the index mark (2) on the stator. If the index marks of both the inlet and exhaust camshafts are aligned to the index marks on the bearing holders, this position is the top dead center of the intake stroke, therefore, the rotor should be turned one complete revolution to bring it to the top dead center of the compression stroke, in other words, the purpose is to place the left hand piston at the top dead center of the compression stroke.
Check the left hand cylinder tappet clearances in the exhaust and inlet valves. Insert the feeler gauge (3) between the cam and the cam follower. If a slight drag or resistance is felt as the gauge is inserted, the clearance is correct. If the clearance is too close or too loose, adjust the tappet. The standard clearance for both the inlet and exhaust valves is 0.0012 in. (0.03 mm) when the engine is cold. Adjustment by loosening the cam follower shaft lock nut (5) and turning the cam follower shaft (4) with a screw driver as shown in the photo. Specific clearance can be obtained at two positions of the follower shaft, but only one of these is the correct adjustment point.

The clearance is reduced when the adjustment is made as shown in the table below.

Right side
Inlet: Turn counterclockwise
Exhaust: Turn clockwise
Left side
Exhaust: Turn counterclockwise
Inlet: Turn clockwise

NOTE: The check or adjustment of the tappet clearance should be performed while the engine is cold. The clearance may tend to increase as the temperature rises. Make sure that the adjustment has not been disturbed while tightening the lock nut, by rechecking the clearance after the lock nut has been tightened.

Next, rotate the generator rotor 180° counterclockwise to bring the right hand piston to the top dead center of the compression stroke and then check both the right inlet and exhaust valve tappet clearances in the same manner as for the left hand side.

tbpmusic · Posted: Mon Sep 08, 2008 8:04 am Post subject:

All the nonsense about finding the cam marks is unneccessary. That's just a method to make sure you are on compression stroke.
My alternate method is to stick my fingertip in the Left spark plug hole and turn the akternator CCW. When you feel/hear the air pressure build up, you're on compression stroke. Turn a bit more till the "LT" mark is lined up, then adjust your tappets (Left).
The cam marks on a 450 can be very confusing and difficult to identify.

Most people use 0.002" for the tappets - the book sez 0.0012", but that's really hard to do, and if you screw up a lot of damage could be done. The Team Hamsen guys set them to 0.005" - a bit of clatter, but otherwise no ill effects.

The adjusters should always turn away from the engine to tighten the tappets.

Once the left side is done, rotate the alternator 180 degrees, to the "T" mark, then do the right side.

Hope this helps......

bill

roncieri313 · Posted: Mon Sep 08, 2008 8:35 am Post subject:

Now that makes sense!...a big help...I assume can use this method to position the pistons for a cam chain only adjustment?

tbpmusic · Posted: Mon Sep 08, 2008 9:08 am Post subject: