ms880 Rebuilding 2007 ms880

[openspaceman]

1 hour ago, TimberTickler said:

I didn't use acid but everything else you suggested I did  this is the result I have. 

I would say those six little patches of grey could well still be aluminium pick up.

 

Can you smear some oven cleaning gel over them with a cotton bud and see if it turns white?

 

I use

 

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and just do it repeatedly until it stays clear.

[spudulike]

I would say the areas are where the plating has been ripped off the bore. It is easy enough to tell - inspect it with a magnifying glass and see if they recess in to the bore or protrude out from the bore. 

Recess = ripped off plating

Protrusions = transfer

It is often difficult to tell from online pics but I think the plating has partially gone.

The good news is the damage is BELOW the exhaust port so if the plating has failed ( I have seen this before), you can often LIGHTLY smooth the surround of the areas around each area of damage (you may already be there) and then just fit the new piston and "see how it goes".

The engine can't see your dilemma, it doesn't sense your reticence in its looks, it just works on if the bore can support the piston and seal when it needs it....the top of the stroke.

The worst that could happen is more plating may come off and mess up the piston. The best is that the bore settles and gives a few more years service.

Give the exhaust port a re-bevel, check the area with a magnifying glass, inspect the bore for any other lifting of the plating and crack on. I have had this sort of thing before and shared these same conclusions with the customer. A new cylinder kit is damn expensive - fitting the piston, getting it running and putting a few hours on it is a better idea IMO.

 

[openspaceman]

24 minutes ago, spudulike said:

I would say the areas are where the plating has been ripped off the bore

Yes once I zoomed in it does look like the plating has come off, it is only about 0.4mm thick IIRC.

[peatff]

It's still below the port, you'll not lose any compression so it's worth a try. Check it again with some acid or oven cleaner just to make sure it's not higher than the plating and clean the port edges up as Spud said. Get a decent piston and rings and crack on.

[openspaceman]

7 hours ago, peatff said:

It's still below the port, you'll not lose any compression so it's worth a try. Check it again with some acid or oven cleaner just to make sure it's not higher than the plating and clean the port edges up as Spud said. Get a decent piston and rings and crack on.

Trouble with that is that it is aluminium under the plating and that will fizz.

[spudulike]

Yes, if the plating has gone....Nooooo to strong acid or alkali.....you are looking at smoothing the edges of the damage a little so the piston just contacts the high & good part of the bore.

[peatff]

16 hours ago, openspaceman said:

Trouble with that is that it is aluminium under the plating and that will fizz.

 

It will be lower than the level of the Nikasil though. 

[bmp01]

9 minutes ago, peatff said:

 

It will be lower than the level of the Nikasil though. 

You risk undermining the surrounding plating though. Especially as the plating adhesion doesnt look too clever - there might be the odd crevice for acid to get into.

 

Bit of a risky game altogether really, a bit more loose plating and that'll be another piston gone, possible bottom end damage and another rebuild. Do Meteor make a cylinders for these ?

 

[TimberTickler]

Hi all, just thought I'd give an update on the 880. 

After trying numerous of workshops who wouldn't touch the saw, I took a punt at doing it myself and we'll, safe to say it runs! 

 

 

 

[pleasant]

On what basis did they decline to touch the saw? Was it because you didn't want them to fit a new cylinder?