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CB550K - engine rebuild (partial or full)

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Erny:
Hello all,

Preparing for engine opening and partial or full rebuild. As I’ll do it for the first time, I’d like to kindly ask for forum experts’ advices/recommendations. I’ll keep thread updated as I’ll proceed. Sorry for long post in advance 😉

Bike is stock CB550K K1, has 17.7k miles total. Engine pulls good as far as I can judge (till 70 mph good, above it not so fast, max speed is about 90-100 MPH)

So let’s start with why I plan this and what I want to address/achieve:

1.   Issue with either camshaft or valve rocker or something else – so need to open valve cover as minimum, more details here http://www.sohc.co.uk/index.php/topic,23227.msg208693.html#msg208693. Along with that I want to replace valve cover by new type, that have fixed rocker arm shafts. But need to find it first. Along with that of course new gasket.. Optionally, if it turns out that camshaft needs to be replaced, I’ll try to find one with improved torque or one from CB650. And of course rockers if replacement needed

2.   Rattling noise @idle coming from head-cylinders (pushing clutch makes just little difference). I’ll make video and post it here, maybe you know that noise and its route cause. Bike idles well, ign. set properly, carbs synced

3.   Cam chain replacement

4.   If head will come off – complete head work – cleaning, valve checks, eventually new valve guides, seals, check for flatness / milling … simply taking opportunity that head is off, check/replace all needed. All gaskets / O-ring / seals replacement. Check/replacement of tensioner

5.   If cylinders will come off – replacement of piston rings. I expect bores & pistons will be OK

6.   Splitting cases is big question now – I’d like to fix shifting issue, but still hope this could be caused by mechanism under clutch (?) http://www.sohc.co.uk/index.php/topic,19775.msg175185.html#msg175185 On the other hand side, having cylinders off, maybe it is good idea to replace all seals, primary chain and check gearbox (?)

Now first questions – before I pull engine and start stripping, any advice what I should do before?

I’m thinking about:
-   leak test (to estimate rings / head status to be confirmed when removed)
-   redo compression test to have reference for comparison after rebuild. Last measurement was: dry: 120/120/110/130 psi, wet (teaspoon oil into each cylinder) : 150/150/145/145 psi
-   detailed inspection of clutch and shifting mechanism under basket – maybe after that case splitting not necessary (?)

Any thoughts / ideas / advices what else I should do before pulling engine / stripping?

philward:
I think you seem to be 'on it' Erny! Hard to comment until you start the strip

Nurse Julie:
I will watch with interest Erny.

Bryanj:
IF you have the motor stripped to base gasket and clutch cover off and you say you are thinking about a primary chain as well as cam chain dont forget the cush drive rubbers in the primary hub, not cheap for a full set but needed if primary chain being done. NOTE:- the 550 casing are slightly diferent castings and the primary can be way more worn than the 500 before it wears the oil gallery

Erny:

--- Quote from: Nurse Julie on October 18, 2020, 09:38:59 PM ---I will watch with interest Erny.

--- End quote ---
thanks Julie, I hope Trigger will give some advice  ;)

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