Louder (than normal) valve noise at idle

[Barry]

So the noise is much worse than before ?

I wouldn't be too pessimistic just yet. It's got to be worth a quick check under the valve covers.

If you can't fix it does this mean you miss the test.  I had a altercation with a Taxi bending the forks in the weeks leading up to my test. I finished reassembling the bike by grafting Honda forks and front wheel on to a Ducati single the night before the test and had quick run around the test circuit in the dark.

[tunnelrider]

I think the noise the noise is now piston clank I and she's got no power, the test was definitely off.  It's bad enough that I'd put it in the 'blown engine' dept for now.  I had a look under the rocker cover when I got home but all appeared to be normal.  Also drained the oil straight away, there wasn't too much in the sump oil but quite a lot of metal flecks in the oil filter creases.  The noise changed during the test ride.

Well done on your ingenuity with the different forks and wheel.  I needed to find a different bike, there wasn't enough time, I'll just have to do it another time.

[tunnelrider]

Just thought I'd give a quick update since I've finally got to taking apart the cylinder.  As predicted she ain't pretty in that there cylinder.

The exhaust valve seat has been partly pushed into the combustion chamber, some of it has broken off and the fragments embedded into the piston and cylinder head, ouch.  The piston also got damage hitting the valve seat.

Does anyone know a method of removing the valve springs or will I have to hire a spring compressor tool?  This is so I can assess the other valves and whether I'll be buying a full valve replacement kit or maybe getting by with replacing the broken valve and seat.  I'm planning to get the valve work done by a specialist shop, don't like my chances of using the kitchen oven.

I've been reading with interest Einar's post about his broken piston and the great advice from you good folk around the world, as I'm assuming I'll have to replace the piston also.  Planning on reusing the cylinder. I'm also hoping to re use the cylinder head, hopefully with the burrs smoothed out.  Does anyone know if this is this ok or not?
Any thoughts or advise appreciated in advance,
Cheers.

[georgesgiralt]

Hello Tunnelrider,
To remove the valves, you only need a pipe wrench of a suitable size, a rag and a hammer.
Put the rag into the combustion chamber as round and tight as you can. Put the head on the workbench with the base on the workbench.
Then put the angled part of the tube wrench above the collet and apply it firmly by hand to the upper spring roundel.
Then give a whack with the hammer on the tube wrench head. No need to be brutal but very quick. The wrench will push the spring only and the two collets will fall in the tube wrench hole. And you're done. Assembly requires the special tool.
If I were you, I'll bring the whole lot to the engineer and ask him what's his opinion. Then ask him what parts I should buy. He will told you and maybe can supply a lot of the parts himself. (mine can).

[montmil]

Difficult to see into that 'black hole' of the cylinder, but you might use a "green" ScotchBrite pad with hot, soapy water to scrub the cylinder wall. No worries about damaging the bore; the Nikasil plating is all but bulletproof.

After a rinse and drying, you should easily see the OEM cross-hatch pattern, If there are no areas where the Nikasil plating might be damaged, odds are in your favor that the jug is good to go back into service.

That piston is definitely toast. New piston and iron rings for sure. That poor cylinder head. I would not trust just any engineer or shop as to the possible repairs. There is a forum member here that discovered that the hard way when her repaired cylinder head / valve seat came back as totally unusable. Save yourself some time and possible frustration trying to remove valves. You already know they are damaged. Get an estimate from a legitimate BMW shop even if you have to pay for their examination and opinion. You'll be money ahead.

Good, gently used cylinder heads show up frequently on eBay. Years ago, I bought a pair of assembled R65 heads for $60.00USD and put them away as an investment in the future. Installed eight years later, they are now running well on my 1981 R65.

Shop wisely, Grasshopper. Post up what you discover.

[tunnelrider]

Grasshopper    True that.

Monte your advice is as solid as ever, thanks.  So you think I should take both cylinder heads to my local BMW dealer to assess, makes sense.  I'll have a look on Ebay for parts.  And George thanks for the method of spring removal, sounds like fun actually!

On cleaning the cylinder, bugger, there's a wee 'nick' in the Nikasil plating.. I'll also take that for an opinion but guess I'm prepared to accept it's also toast, I've ignored too many things lately.  The wee nick is barely noticeable by running a fingernail over it.  It's visible in the photo's as the bright fleck roughly 6'oclock, half way down the cylinder in the first photo and a black spot roughly the same spot in the other two.

Back to research and weighing up the economics vs emotional attachment!  I'll keep you guys posted. Thanks for your good advice.

[georgesgiralt]

Sorry to hear about the nick.
If you have to go to the new parts route, bear in mind that Siebenrock is selling a 860 cc kit for less than it cost from BMW.
You should see a dealer with you jug and ask him what is it's opinion. I've been told that repairing Nickasil coated jugs is possible (and often done on off-road motors) and quite "cheap".. (regarding new jugs)

[montmil]

Man, T'rider, I hate to see that.

Might check in with Motobins and Motorworks over in Jolly Ol'. Beside parts, they are also breakers and might be able to get you a complete top end that's in good nick. Might save a heap o' money.

Don't rush your decision. Research options before you pull the trigger.

[Luca]

There are folks that apply nikasil to ultralight aircraft 2-stroke cylinders.  Racer's do it too.

A quick google search turned this up http://www.racerstoystore.com/replating.html  They charge about $200US, more if they need to repair gouges, etc.

Maybe there is someone in your area.

[tunnelrider]

Back on the road after almost two months!  Had the damaged piston inspected by an engineer and a BMW trained m/c mechanic who both recomm. to re-use it after smoothing down the sharp edges.  Bought a spare 1980 R65 engine. Swapped my '85 con rods (one had worn so much the rear oil passage on the big end was ground down to almost no passage) with the donor engine con rods and new big end bearing shells.

Re-using my original barrels and pistons + new piston rings.  Using the donor 1980 heads while my '85 ones are still at the shop, she runs much smoother now!  Great to be out on the road again, although a bit of a run in for the rings the next couple of weeks.

[montmil]

Pleased to hear both bike and rider back on the road.

When the rebuilt heads return, and I'm sure they will look great, perhaps consider taking a quick look at the bore with the Nikasil chip. I would bet it's small enough to be a non-issue.

Stay safe, mate.

[nhmaf]

Better sounding news, at least!

[tunnelrider]

Thanks Monte and nhmaf.  Yes I'll pull apart the top ends again once in the depths of the south hemisphere winter, to put the reconditioned heads on and no doubt will take a very interested look at the 'nick'.  I'll keep in mind the joy a photo brings to all!....