The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: tunnelrider on February 12, 2016, 01:28:57 AM
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Hi everyone,
With the engine at operating temp in mid summer I'm getting a random loud metallic chatter from one valve on the right cylinder at idle, sounds like a valve hitting something alloy-ish.
The metallic noise comes on and off at random for 2-5 secs while idling, matches the normal valve rhythm, is very noticeable at idle but not at all while under load and produces a wee duff exhaust note if right up at the back of the exhausts pipes. It doesn't seem to be occuring under way or when the engine's cold.
I've checked and adjusted the valve clearances (the last time was 11,000km ago, gee, already?!), topped up the engine oil and opened up the idle mix screw a little, which have all had no effect on the problem. The bike runs normally otherwise but I haven't checked the timing lately.
I feel a bit lame for posting this as I'd like to have investigated a bit further before posting, but I've got a licence test in a few days...!
Thanks for any advice,
Dan.
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Rocker shaft end float ? what's the adjustment method on an 85 are they shimmed ?
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Hi Barry, thanks for your reply. Yes the '85 rocker arms are shimmed. I measured the rocker arm end floats when I did the valve clearances. On the problem cylinder the intake end float was .229mm, the exhaust was nil. Perhaps this should be more? I haven't adjusted the rocker arm floats since owning the bike and put 20 000km on the clock. The valve noise has always been pretty noticeable but there is a problem noise now (prob started approx 1000km ago).
BTW, the left side which doesn't have the valve problem have end floats of .254mm (intake) and 0.074mm (exhaust).
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Hi,
I won't alarm you, but you should remove the valve cover.
Why I say that ? Because last time I had this noise on my R65 it was because I had broken a valve spring.
And I stop riding just before the valve broke due to that...
But YMMV
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Hi georges,
Yes so you're familiar with the noise. Dammit, I didn't want to believe it would be a broken spring but you're right, I need to assess whether it is. I have to admit I've been riding her as fast as she'll go before this problem. I'll check tomorrow, thanks for your reply.
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When I broke an exhaust valve spring, the performance hit was noticeable. I did not notice any noise before hand, but I wasn't necessarily listening for it. The spring broke at start up, though. Parked the bike at the office, was a normal (fast) commute in, going home was brutal. Probably shouldn't have ridden it in that state.
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Thanks Matt for your input. Unfortunately I didn't get a chance today to have a closer look at the rockers and springs, will try my luck tomorrow, if my better half doesn't mind me spending time with my other girlfriend in the garage on Valentine's Day...
In reply though there hasn't been a discernible difference in performance or exhaust notes while riding. But she's gonna be parked up now 'till I find the cause.
I need to buy an exhaust nut spanner too, anyone got recomend's? I've avoided this so far as the postage to NZ will prob. be more than the spanner.
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In order to check, you only need to remove the valve cover. It takes 5 minutes each side. Then you can decide if you have to remove the heads or not...
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This is the one I have
The compact size may not be as bad to ship as some others
http://www.cycleworks.net/index.php?main_page=product_info&cPath=29_33_51&products_id=346
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Why would the head need to come off for a broken valve spring?
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Well IF it is a broken spring !
Once the noise origin ascertained, the OP will have a decision to make.
If the spring is actually broken, and he has ridden the bike, the valve and valve guide could have suffered (this is what I saw on my head). Then, if this hypothesis is correct, the head should come off.
But we are just speculating here.
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What kind of damage did you see, George? I've had to remove valve springs in a V8 and just needed to bring the piston up top to keep the valve from falling all the way in... Actually, kind of stuff as much 1/4" nylon cord/rope into the cylinder then crank the piston up a little...
That being said, if you suspect damage on piston side of the head it would need to come off.
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Even if he doesn't need to remove the head at this time .
It is still a good idea for a Airhead owner to have some of the basic special tools handy.
The exhaust nut wrench is one of them.
The rotor removal bolt and swing arm bearing socket are others.
I almost forgot the heat gun ::)
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Hi again,
Mrclubike that's right, an airhead owner should have an exhaust nut spanner. I've been meaning for a while to sort out the low compression on this cylinder, which was existing before the noise. If it was winter I'd be getting right into the barrels. I want to replace the piston rings, the base gasket O-ring is leaking and I've expected something to be done with the valves. But anyway with the rocker cover off there was the following:
- The R65 on the centre stand is able stay upright through a 5.7 earthquake centred 10km away (no s&%t!)
- The valve springs are not broken although the exhaust spring has been installed up the wrong way, with the painted end towards the rocker cover.
- There were a few metal filings, magnetic, on the rocker arm support blocks, mainly the intake side.
- The intake rocker arm has a larger shiny area where it is pushing on the valve, due to the larger axial play, than the exhaust (see photos).
- The exhaust push rod has a few marks along it but no gouges have been worn in.
I'm thinking my next step should be to order a few shims to reduce the intake rocker arm axial play and see if this makes a difference.
Because the four nuts holding the valve rockers are off, oil has weeped out of the barrel base o-ring gasket. Can I just tighten up over this?
Cheers for all of your input, you guys are great.
Dan.
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Uh oh, the brutal (big up's Matt) ride back home, the ride from hell where you just want to ride into a hole and come back out with a broken shoulder to think about rather than a broken bike! I now know what it's like...
Against all good wishes (and thanks for your advice George) I bloody put the rockers back on and took her for a test ride up a hill so I could sit my full bike license today. After starting alright I clanked back home at 40km/h. Well I knew I was asking for trouble but kinda hoped I'd be lucky!
So I'm gonna get stuck into the barrels, just like it was winter! But I cant tell what or how bad 'till I get an exhaust nut wrench. I can see by looking down the spark plug hole that it's very oily in there, I'm expecting a whole lotta trouble. I'll probably post again when I'm climbing out of the hole, hopefully without the spade. ;)
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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.
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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.
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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.
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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).
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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.
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Grasshopper ;D 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.
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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)
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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.
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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.
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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.
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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.
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Better sounding news, at least!
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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!....