Is this master cylinder original or reproduction

[Craizeehair]

Would anybody be able to tell me if this is genuine or perhaps original to the bike? I recently bought my old K7 back after a few years, the last owner had fitted an aftermarket master cylinder but the rubber bushing and retaining plate that sit underneath are missing, so there is a load of free play on the lever.

I messaged the guy and he said that he still had the one that he took off and has kindly posted it to me.

I’m hoping to confirm that it is original so I can go ahead and refurbish it and fit back on the bike, this one doesn’t have the retaining plate like I have seen on others, I am going to strip it down soon but if it’s an aftermarket part like the one on the bike now, it probably doesn’t make sense to refurb and fit this one.

Thanks in advance

[JamesH]

Original not repro


Sent from my iPhone using Tapatalk Pro

[Craizeehair]

Original not repro


Sent from my iPhone using Tapatalk Pro

Thank you, much appreciated.

I shall set about stripping, cleaning and fitting the refurb kit. I’m very happy about that. 

[Johnny4428]

That retaining plate and bushing was missing from mine too a little while back but resourced from CMS no problem.

[Laverda Dave]

Don't try to repaint the body, I understand it is some kind of anodised finish and is one way to tell the original from a repro, genuine have a mauve type finish as yours has. If you try and paint it the new paint will flake off over time but don't ask me how I know this 

[Oddjob]

Unless you get it ceramic coated Dave, impervious to brake fluid. Saying that I haven't been able to test the theory yet until I get the 500 on the road but it should work and looks like a standard finish when new.

[Craizeehair]

Thanks all, I’ve cleaned it up and fitted the rebfurb kit but like a wally I forgot to order the diaphragm, I need to order a few more bits soon so I will make sure it’s on the list then.

I will do an oil change with filter in the not too distant but I made the mistake of reading some of the ‘what oil’ threads and now my brain hurts and I need to curl up in a darkened room!

[Oddjob]

When changing the oil please be aware that the oil filter bolt has a large spring fitted but also has a large steel washer on top of the spring, this often gets stuck to the filter and gets thrown away with the old filter. It's vital this washer is fitted or you risk the spring puncturing the filter seal and that can lead to catastrophic engine failure. It's part 8 in this diagram  https://images.cmsnl.com/img/partslists/honda-cb550k3-four-england-oil-filter-oil-pan_bigma000085e11_5e54.gif https://www.cmsnl.com/honda-cb550k3-four-england_model14671/seat-oil-spring_15414300000/ a lot have been accidentally thrown away by previous owners and if you don't know it's supposed to be there you wouldn't spot it was missing.

[Craizeehair]

Thanks, I will keep an eye out for that. I also read on her somewhere that someone had tested four out of 5 oil filter housing bolts and found them to not be working correctly, I did wonder whether it might be wise to order and fit one of these as well?

[Martin6]

Could someone explain how the oil flows through the filter system / how it works?

[andy120t]

My CB550 original one is a faded purple too..it looks far nicer than the replica ones. Patina!

[Oddjob]

Could someone explain how the oil flows through the filter system / how it works?

Comes from the oil pump, which sucks it through the strainer in the oil pan or sump, the oil pump feeds the oil filter, it flows on the outside of the filter and strains through to the centre of the oil filter bolt which then feeds the crankshaft first which in turn feeds the conrods and the oil reducing valves which are fitted to the barrels before they go on, this then feeds the camshaft journals and then flows back down through gravity. The rest of the engine is mainly lubricated by a splash system, with all those moving parts inside the engine there is a lot of oil being thrown around. This is on the 500/550, the 750 has a completely different arrangement. The 550 also has a small oil pump in the gearbox but that's not really part of the oil system.

There is a relief valve fitted to the oil pump and another fitted to the oil filter bolt, the filter bolt one is one I've recently found to be sticking, I tested 5 bolts and only one worked as it should, one was jammed and the other 3 were sticking. This relief valve is just a small cup with a spring which forces it up inside the bolt, the spring is held in place by a small roll pin. To test the relief valve get a small piece of right angled metal and slide it into one of the holes right under the nut end of the bolt, you can see the relief valve up overing up the next layer of holes, press down on the cup and the holes should become exposed, it should then move back into place when you release the pressure on it. The idea is that if the oil filter blocks or collapses (which one of mine has in the past) the pressure of the oil will force the cup down, oil will now flow through the top holes and exit the next holes down, these holes will be inside the filter when it's in place. So it bypasses the filter and allows oil to go into the engine but of course it's now unfiltered oil so it's not a good idea to leave it like that.

That help?

[robvangulik]

A picture says more than a thousand words?

[Martin6]

Thank you, I know it's not rocket science, but I'm struggling with how the bolt and filter are sealed, so that only filtered oil continued onwards. Plus how the pressure relief arrangement works. The picture helps. I know I don't need to know, just interested.

To check:
- The fixing bolt (with the holes in) screws into an engine supply 'gallery'. Does it have 2 different types of holes, one set for filtered oil and one for unfiltered (when pressure relief is required)? With the main supply holes in the bolt inside the filter, passing filtered oil into the motor via the gallery?
- The spring which requires the washer (which the bolt goes through), is it only there to push the oil filter hard enough to seal against the bolt on the flange outside that engine supply 'gallery', also ensuring the pressure relief mechanism section of the bolt is outside the filter?
- The pressure relief holes in that bolt. Are they are outside the filter (in the end section within that outer spring)? Does it work so, as flow gets restricted by an increasingly dirty filter, pressure builds in the oil filter housing until it pushes down the spring inside the bolt and unfiltered oil is forced through those pressure relief holes in the bolt and straight into the gallery?

[Craizeehair]

There is a relief valve fitted to the oil pump and another fitted to the oil filter bolt, the filter bolt one is one I've recently found to be sticking, I tested 5 bolts and only one worked as it should, one was jammed and the other 3 were sticking. This relief valve is just a small cup with a spring which forces it up inside the bolt, the spring is held in place by a small roll pin. To test the relief valve get a small piece of right angled metal and slide it into one of the holes right under the nut end of the bolt, you can see the relief valve up overing up the next layer of holes, press down on the cup and the holes should become exposed, it should then move back into place when you release the pressure on it. The idea is that if the oil filter blocks or collapses (which one of mine has in the past) the pressure of the oil will force the cup down, oil will now flow through the top holes and exit the next holes down, these holes will be inside the filter when it's in place. So it bypasses the filter and allows oil to go into the engine but of course it's now unfiltered oil so it's not a good idea to leave it like that.

That help?

Can these be brought back to life if they are sticking or is a replacement bolt?