Topic: Learning: For all who have asked about 550 Tensioners...

[Jonesy]

I tore the top end off the wife's CB550K tonight so I can replace the leaky oil gallery O-rings that feed the valvetrain. Since many folks have asked about how to adjust the tensioners on these little beasts and debated over how they function, I figured I'd post some pics of the tensioner assembly, as well as what can happen if the cam chain is not properly tensioned.

Here's is the tensioner body, with the tensioner blade removed for clarity:


Here's a close-up of the adjuster mechanism. I thought both ends had moving slides with gear teeth, but I was wrong. One end of the tensioner blade is held fixed while the other end is movable. The gear teeth are circled:


Lastly, here's the worn tensioner blade:

[bryanj]

That tensioner blade is good for lots more 1,000's. The "rails" of the chain eat into the rubber until the "rollers" are bearing on the rubber surface. Only change when ANY ONE of the following is apparent; the middle is significantly lower than the edges, steel shows in the "grooves" or cracking is apparent where the rubber bonds to the steel backing at the ends.
A New fittment would have grooves in it within 1,000 miles--hence the rubber bits in the oil pump screen!

[Jonesy]

Thanks for the info, Bryanj. The rubber is showing cracks at one end. I already have a new blade on order.

[bryanj]

No problem at all mate, when you consider how old all our rubber tensioners are, they really all aught to be changed. Worth looking at the cushion on the other run for any fracture marks as they do, occasionally and rarely, break up

[L.A. Nomad........]

Where are you getting your replacement from? I'm getting ready to replace many of the seals and gaskets on my motor. My motor has about 50,000 miles on it. So I guess I should check the tensioner too!


Nomad

[Jonesy]

Worth looking at the cushion on the other run for any fracture marks as they do, occasionally and rarely, break up

The chain guide on the "tight" side of the cam chain looks practically brand-new.

Where are you getting your replacement from? I'm getting ready to replace many of the seals and gaskets on my motor. My motor has about 50,000 miles on it. So I guess I should check the tensioner too!

All the top-end seals are still available from Honda, but they don't have the top-end gasket sets anymore (Last quoted price was about $74.00) and ordering all the bits individually runs around $150.00, tensioner blade not included.

Here was my order for the 550, less the other misc. bits I needed for other projects:

14520-323-000, SLIPPER, TENSIONER  Quantity: 1 
91305-323-000, O-RING (5.8X1.9) Quantity: 1 
12191-426-306, GASKET, CYLINDER, Quantity: 1 
91301-426-010, O-RING (4.9X2.5) Quantity: 2 
91310-426-000, O-RING (11X2.5) Quantity: 2 
12251-374-306, GASKET, CYL HD Quantity: 1 
91318-300-013, RUBBER, SEALING Quantity: 6
91302-001-020, O-RING (30.8MM) Quantity: 8
 12391-323-000, GASKET, CYL HD CVR Quantity: 1
12329-323-000, GASKET, BTHR CVR Quantity: 1 
91319-323-000, O-RING (6X3) Quantity: 4 
18291-390-306, GASKET, EX. PIPE Quantity: 4