Started Engine strip & Rebuild

[Gromitdog]

Hi All

I have decided to started my strip down on a 550 engine with advice and what to beware of from Ken, which has been a great help so far.

All went reasonably well cylinder cover came off ok along with the cylinder head & all the valves bar one came off easily bar one exhaust valve which required a gentle tapping out on further investigation I found that only the small washer was fitted under the valve springs and the large washer was missing which leads me to believe that possibly the exhaust valve is slightly bent as other valves fit in that position np there is lucky no damage to the piston so have been lucky there.

The main block was really hard to get off and had to be tapped off using wood and wedges got even harder as we eased the block up the main studs This turned out to be corrosion in the holes which left a rusty paste like crud on the and below the stud top threads. So they will need a die running down them to clean them up.

The bores are looking clean and I have applied general grease to them until I get round to measuring them up. Small ends 1&4 came out easily but 3&4 needed to be tapped out with a 8mm socket and showed signs of corrosion in both of the small ends and gudgeon pins .

Would anyone have spare exhaust valve and the large washer in the spares draw that I could purchase please.  As I take it that the gudgeon pins and small ends can be repaired ?

Gromitdog

[Murf]

Hi The lack of washer under the spring would not have made any difference to how far the valve was being pushed down into the cylinder when the valve was opened. The valve height is set by its seating on the valve seat and its distance of travel into the cylinder is set by the cam lift and tapet adjustment.  The washers job is to protect the soft aluminium of the head.  Clean off the corrosion from the piston pin and see if there is any pitting on the pin, if it is pitted in the areas where it makes contact with the piston or small end then it might need replacing. If the corrosion is just in the none contact areas or no pitting has occurred then I would clean everything up put the piston pin back in the small end and check if there is any discernible up and down movement in small end/piston pin joint.

[Murf]

BTW if you are going to use new pistons in your rebuild they will come with new gudgeon pins. I don’t know if the small end is bushed or just bored in the metal of the con rod. I have my 550 in bits so will have a look.

[K2-K6]

The missing valve spring support washer, as already noted above, won't change how far it moves but, it will decrease spring preload on the valve with the possibility of valve bounce at high rpm.

It may have been affected by that and just touched a piston, that's a possibility. Anyway, a new valve should sort it.

You can check a valve for being straight by just rolling if on stem and head periphery on a piece of glass to see of the mid part of the stem runs true.

A cooker hob, if glass, makes an easy "surface plate" to roll it across. Dont get caught by owner of surface plate though 

[Bryanj]

The large washers frequently are there but dont feel like it, try using a magnet to see, i can probably find a used valve and washer if needed but check for everything else you need first as postage is dear.
Replace gudgeon pins and check small end in rod, as said if you rebore piston kits come with pins anyway.
Very common for the crud in stud holes, many times have had to use the threaded ends to "ream" the holes on dissasembly.
Are you going into the bottom end?

[Gromitdog]

Thank you to all that replied to my post I never done an engine strip so this is all very new to me so thanks for all the advice and guidance. Just going to take my time and plod through it .

Gromitdog

[Mike_Berkshire]

I will be following your progress with great interest as I’m doing the same. (‘76 US import 550K) Currently my top end is in bits although I have de carboned the head, pistons and valves, re ground the valves and replaced all the valve seals. I will get round to putting the engine back together once I have rebuilt the front end of the bike. Forks and front brake done and next is switchgear and clocks.

Good luck!

[DomP]

You're in safe hands Gromitdog, I rebuilt my CB550F following advice from Bryan, Ken, Roo and Ted to name a few having never done an engine rebuild before.  Just done rush any stages and expect it to take longer than you might think and you'll be fine.

[Bryanj]

bownload the complete 500/550 manual from Ashs dropbox, if it isnt specified in your particular supplement its the same as the 500

[davidcumbria]

I found this article really helpful.

https://www.dropbox.com/scl/fi/qkzj4s8ivns2f58oep7wu/Classic-Mechanics-1988-Engine-Rebuild.pdf?rlkey=tamoibyqmtgwqveiyd3528z2p&dl=0

[Gromitdog]

Hi Dave
I get it printed off I sure it will help with the strip down & rebuild thanks.

nige

[McCabe-Thiele (Ted)]

When I dismantled my first Honda engine - a 400 in 2020 - I found taking plenty of photos really handy especially when dismantling things like kick start shafts, any gearbox shafts, clutch assembly, cable runs etc etc. I took well over a hundred photos during my 400 strip down - even then it was not enough when it came to putting it all back together again.

I would take a start photo then as I progressed take part dismantled photos. Even stuff that looks obvious where it fit's might not be obvious a couple of months or more later when you put it all back together.

I had a Haynes Manual plus looking at builds here like Julies 400 engine strip - (those pistons were bad!)
If I got stuck obviously I asked here after searching a subject.

After dismantling my 500 I spent hours looking for the main rear brake return spring. Eventually I checked my start photos to realise I had been searching for something that was missing from the start!

Also the odd hidden sneaky bolt when you are trying to seperate an item. Lastly when you find a bolt that does not want to come out - take your time - use plenty of releasing fluid etc. Put bolts in a labeled take away box or zip lock bag. Keep bolts with the covers or part they belong to etc.

Lastly when you hit a problem thinking time is important - when you need a new part don't rush to order it - ask here first it might save you money. Sorry if I'm stating the obvious - we all have different levels of ability in different areas.

Lastly Gromitdog post a project build here so new members can share your build.

[Johnny4428]

Parts diagrams too Nige, very good for checking everything is correct and in the right order. Good luck and look forward to further updates.

[Mike_Berkshire]

I have found using stackable plastic storage boxes really useful. Tesco are the cheapest I have found.

[Gromitdog]

Thank you ALL for the continued help and advice & guidance from you all, Just looking into some plastic boxes with clip handle lids ( will be repurposed on another project later ) to store the finished tappet cover, cylinder head and block in when they have been finished to keep them safe until ready for use.

IPC diagrams are great as it shows you all the part in the right order 🤗 and not how you think they should go 😂

Parts are so far bagged and labelled, Open engine covered over and blanked around con rods with rag. cylinder bores are covered in general medium grease to protect against corrosion

Will keep you updated on the progress

Nige