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The current project (CX500 79 CDI) I am undertaking seems to have become a little more involved than I had originally thought it would and I have now dropped the engine in order to check the cam chain and replace the mechanical seal. Whilst it wasn't too hard to do, I do have a few questions that I would hope the more experienced would be able to answer.

First thing was to remove the camshaft cover on the front of the engine as it was leaking oil, man it was a pain to get out, but eventually wasn't an issue, I have a replacement on the way and some new gaskets/o rings to go with it, sorted hopefully! The rubber seal on the front was as hard as plastic!

The water pump assembly was also fairly simple to take off and the impeller was no problem to remove (Have kept the copper nut!). The previous owner seemed to have a thing for using a large amount of sealant with the gaskets which was a nightmare to get off and there was a lot of silicone residue within the system itself... not great. I pulled at the old mechanical seal and with no resistance at all it popped out (shows that the idea to replace it may have been good!) I plan on using the "shep" method of doing it as the metal part is still in there and I have spares lying about with sealant glue. - (is there another one needed for the back? / rubber seal or something?)

Drained out all the engine oil before removing the back of the engine (in hindsight probably should have done it before dropping the engine...Doy) a little metallic but I don't think it's too serious (advice please? :p )

Water


Taking the back plate off the engine was a little more tricky, getting the bolts off was a little tough as they had been JB Red Threadlocked in place - jiggling it out was also a bit of a ballache.. Was introduced to a pretty clean interior (with of course masses of sealant around the outside).

First thing that hit me was absolute dread as there were what looked to be huge pieces of metal on the inside of the case, however after further inspection it would appear that these lumps actually ARE the case. They are solidly on there and are the same colour so I presume it's just the casting.

Auto part Engine Tire Automotive wheel system Wheel


Second worry was the grey gunk in the bottom of the engine I have been told that this is normal residue from older engines - however it strikes me as very odd that the previous owner would go to such lengths to replace all the gaskets (and apply so much sealant lol) but not bother to clear out all the sludge at the bottom - strange right?
Whilst removing the sludge, I came across a loose washer embedded in it... Which made me thank god that I had taken the engine apart before running the bike properly - but also now worry what on earth it could be from...

Auto part Metal Crankset
Red Pink Magenta Tape measure Circle


The cam chain didn't look in such bad shape either, not loose by any means and by the looks of the tensioner there is still some life left in it? But again, some advice would be great.

Auto part Gear Engine Metalworking Automotive engine part
Auto part Gear Engine Automotive engine part Bicycle part


Oh and also, it would be nice to know what sort of o-rings these are as they need to be replaced.

Auto part Engine Rim Wheel Metal


Finally does anyone know how these gears are supposed to mesh as they came away when the back was removed?

Auto part


Any other seals, gaskets or anything that need to be replaced or looked at too?! Any advice would be greatly appreciated

Thanks (and I am really sorry it is questions galore, my expertise on these engines is non-existent and I really don't want to mess up.
 

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Those orings are part number 9460850000. There is great documentation on this website to download that has teardowns and part numbers of everything. The FSM is also great and shows how everything goes back together.

The "chunks" in the bottom of the rear case are the case itself. Looks way cleaner than mine did!
 

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Thoughts: miscellaneous and not sorted ;)

- It's not a copper nut but a copper washer and a nut with a head.

- The tensioner arm will not tension because the is a burr/fin on the hole on the arm.

- The chain is ready to go into the bin.

- The dirt/gunk is magnetic ?

- CX500 97 CDI ===> it's 79 ;) <<**Mod edit, corrected**

- The embedded washer is maybe the one of the gear shift spindle

- To see more suspicious things and to change the cam chain You have to remove the fly wheel. (to remove it You need a puller-screw M20x1,5mm (IIRC))

The last answer for the moment :)

Auto part Engine Machine Automotive engine part Carburetor
 

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Discussion Starter · #7 · (Edited)
Thanks everyone for the help! I have checked the tensioner and bought myself a new cam chain, as well as the orings and a new mechanical seal. You were right too, that washer is off the gear selector lever! I have begun cleaning out all the gunk at the bottom too and will hopefully get everything running within the next week or so!
 

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'84 CX650E that is evolving into a GL500
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While you are in there examine the starter clutch. The replacement springs, caps & rollers to rebuild it aren't very expensive and you have to remove the flywheel to get at it. Also, test the camchain guides to see if the rubber has hardened - if you can dent the rubber with a thumbnail they are OK of it is too hard to dent replace them.

Oh, and DO NOT CHEAP OUT and try to re-use any of the o-rings, especially the one on the camchain tensioner bolt. You really don't want to have to drop & open the engine when it fails and engine starts running down the back of the engine :rolleyes:
 

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only buy honda starter clutch springs at 3 dollars each you can afford it

i have seen and fixed some of the clutches fixed with ebay kits that did not last 2 months on a 500 and just weeks on a 650

the springs are brittle and break in half
 

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under the impellor , on the end of the shaft is a steel shim washer. It may be stuck in the recess on the rear of the impellor even. Do not lose this as it is the distance spacer to prevent the impellor rubbing on the housing on reassembly.

Also , while the motor is out , pull the front cover and service the oil pump chain and intake screen. This should be done regularly anyway but no one ever does.....
 

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Good idea. If there are blobs of silicone floating around in there they will (hopefully) accumulate on the screen.

BTW: I won't argue whether you found it inside the engine but the only silicone I can see in the pics is around the bolt holes. For some reason people seem to get the idea that it should be applied liberally and the parts assembled while it is wet as if it was glue and that often results in blobs of it being extruded into the inside of the engine which can break off and flow around inside with the oil.

Silicone can, if used correctly, help gaskets seal and greatly reduce the labour the next time the engine is apart by preventing the gasket from becoming bonded to the metal. The correct way is to smear a very thin layer onto both sides of the gasket and hang it up to cure overnight before assembly. But if the mating surfaces are in good shape the gasket shouldn't need any help and smearing grease onto it before assembly will ease disassembly just as much without the need to wait for it to cure.

Also, if smearing a dab of silicone on the threads of a bolt before you screw it in it will seal moisture out of the threads, preventing corrosion. It leaves residue in the bolt holes like the orange silicone in your pics but that is easy to remove.
 
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