1981 R65 Harsh Knocking

[matthewjp14]

Hey, not sure where to start with this one but my r65 gained a new harsh loud clacking/knocking today in the right side valve area. Its definitely right side and my long screwdriver I'm using as a stethoscope tells me the valves get a lot of that noise, but it could be piston/piston slap related if people think thats something that could happen. Maybe the sound echoes through the valves the most in that scenario.

Iv'e done a lot of work on this bike, cylinder heads were just finished by Ted Porter's last year so in theory those are well taken care of. I have to assume no burnt valves. I have regularly (every few months) checked compression and adjusted valve lash when needed. Its never been out of the range of 120-140 and typically after resetting runs 135-140. Its getting gas and air so the only thing potentially unchecked at this point would be unhealthy spark but it hasn't had serious running problems since shaking off the cobwebs after valves being done.

I might be done here. I'm not sure how else to tackle this. Just sat down in the garage and walked through valve lash, rocker end play, timing, and studs torque on both sides to be sure and it changed nothing. Its made the knocking hot and cold. Even runs like a champ. I technically have a spare engine including rockers, pushrods, and all which may be worth swapping parts in and out to try and locate a problem but I'm just baffled this kinda noise would come form nowhere and get so deafeningly loud in a day. These bikes are known for loud valves, but this is an intermittent, typically on dropping rpm, isolated noise coming from one side. Left side still sounds like it used to.

All advice is appreciated.

[georgesgiralt]

Hello Matthew,
Been there, done that. So I know how you feel.
I would set the valve lash properly, first, then check if the noise has disappeared or not. Y ou will also be able to see if something is amiss when opening the valve  cover. (I had, once, a valve spring broke and, boy, that was noisy...)
Then, as you have removed the heads and put them back, I would check that the exhaust big nuts are properly seated and torqued.... If somewhat loose, there is a gas leak which is noisy....And don't ask me how I know.
If the nut is not set properly, refrain from torquing it more. unscrew it, clean the threads and put high temperature grease before putting it back. Otherwise you are going to have problems somewhere down the line...
Hope this helps.
P.S. : Do not forget to check the spark plug. if not set properly, the leak also make funny noise.

[Bob_Roller]

This is 'interesting' tp say the least !!
You have to start somewhere .
To eliminate the ignition system swap the ignition lead and spark plug from the good cylinder, I really don't think it's the problem, but you're just trying to eliminate possibilities now .
I would remove all the valve train parts on the affected side and give them a good inspection .
I had the rocker arm bearings fail on my '81 R65, the sheet metal shell broke out on the flange that hold the needle bearings in, I found several needle bearings missing on those bearings, but I also found the chewed up parts in the valve cover, again I don't think this is the case here .
If you don't see anything wrong, I'd swap in parts from your spare engine and see if anything changes .
By chance if you didn't know this, the rocker arm shafts have a drilled oil passageway .
It's been over 10 years since I had the head and cylinder off of this bike .
Oil supply for the rocker arm parts comes from I believe the lower cylinder studs, the corresponding hole in the shaft has to be on this stud, facing toward the cylinder head not the valve cover .
Hope that made sense !!
Did you have the cylinder off during your major work ??
Did you use any sealant in the area of the o-rings on the engine case where the lower cylinder studs come out ??
There's been a few reports of clogging the oil supply to the valve train parts because of sealant used in this area .
I don't know if any of this will get you closer to a solution to your issue here .

[dogshome]

Sudden, deafeningly loud tapping/knocking says something has let-go to me. Valve spring, rocker arm bearings, yes, little end, maybe, piston slap, maybe, big end even. Whatever it is, taking it to bits that side will quickly reveal it.

I wouldn't go riding around much (at all) until you've found it, or it'll take itself to bits. 

[matthewjp14]

The engine currently in the bike was swapped 2 years ago. Health wise, it sat for roughly 2 decades until I decided it was worth putting time and effort into over my engine (sitting in boxes) threw an exhaust valve at the piston. This 'new' engine had somewhere around 35,000 original miles on it. PO and I both have no idea what went wrong with it for it to go and sit for 20 years but the motor was in decent shape after replacing seals.
After getting it running, about a year in, I got valves done by Ted Porter's. Truly A1 work. It's ported now, makes a hell of a lot more power than the original tired valves did on my 150k+ engine.

The things I did not replace or check on this replacement engine would be the crank (seemed to spin fine), thrust bearings (same logic, knew for a fact they were intact), and the timing chain and tensioner (just didn't feel like opening it up and paying for pullers and more parts on my minimal college budget). Every other gasket was replaced. I also know the ignition circuit needs looking at so that will be on the agenda to replace wires and plugs as well as double checking coil values.

As far as the events 2 days ago are concerned, first thing I assumed was amiss was a bad valve lash. These guys are known to go in/out of spec seemingly randomly and with changing seasons it could've warmed up enough to change things. Before that compression was at 130 both sides, after it was 130-140 both sides. Both sides were in spec for gaps before and after. I made sure oil is flowing through the rocker arm galleys and it pumps out the top of the rockers on both. Checked needle bearings on the exhaust valves on the noisy side and they seemed to be doing their job; I'm not an expert though so theres a possibility it isn't something my untrained eyes can pick up on.

Once I have time to dive in, it will be a good idea to swap in the valve train from the spare sets. Other than that though it's internal and I will need to start digging into it big time. If I have to guess the old brittle timing chain tensioner could have gone. It's not out of time yet but I never cracked the front case open so I'd be willing to look into that. My next guess would be piston slap or dropping a piston ring. It's totally possible something went wrong in the bottom end. Maybe something with lifters. Couldn't be sure.

This is all If I'm able to get to it before taking care of my 89 4runner's blown bottom end already fully disassembled and been waiting for a chance to take care of it. I have to take that to a machine shop though so who knows what lead times are like during the spring. Probably several months which will give me time to focus on this bike. Will be updating when I have information on miraculous recovery or certain destruction.

[donbmw]

To me it sounds like connecting rod main bearing. This is going by having ba bearing suddenly go on my TR3. But on my R90 I had light knock that would come and go. Finally pulled cylinders to fix oil leaks. Found piston pin connecting rod bearing bad. Replaced bearing and that knock went away.

[matthewjp14]

Update on teardown. Light work today, pulled off the noisy right side cylinder to check things out. I was expecting the worst but was actually pleasantly surprised. No piston slap, no cracked valves or seats. no broken piston rings. All the crosshatching looked as fresh as ever. There was also no discernible play in the wrist pin/main bushings. They swiveled clean and straight. No pushing or pulling revealed any serious play.

All of that to say the good signs here make me more confident in my past work and hopeful that we're looking at a simple timing chain replacement. If I had to guess, the tensioner arm or guide was broken loose and is now captive, rattling away inside the front right cavity where the chain lives. I've never taken that cover off before but it seems to be straightforward minus concocting a puller tool for the front cover from potentially plumbing fittings.

I'll attach pics for context but almost everything here seems generally healthy. The only thing I was unsure of is the pushrods. Theres a ring around both that I can feel with my fingernail. Is this normal? It doesn't seem to be aggressive.

[dogshome]

Thanks for the photo updates, keep them coming. A detailed, concluded thread is always welcome 

[matthewjp14]

 

 I gotta break these guys out more often.

I'll just be waiting on tools before making any advances on the teardown. I've never pulled a front cover off these bikes before and just purchased the rotor helper tool too. Anybody have any tips for pulling that front cover?

[Bob_Roller]

Mark the position of the ignition canister .
I use a scribe to mark the canister and the timing case .
I’ve heard of problems not using the hardened tool for alternator removal .
There is a paper gasket that goes on between the timing case and the engine .
There is one small gasket, looks like a paper washer, it goes on around the center of the timing cover, if you neglect to put it on you can get seepage of oil into the ignition can and alternator area It's been 10 years since I had this cover off .
I believe there a different length fasteners that hold the cover on may want to make note of this upon removing it .
And I think there may be some spacers on some of the fasteners as well .

[Bob_Roller]

Do you have any plans to replace the timing chain
Here’s a little tip that helped me out with installation of the timing chain .
Take the old master link and bevel the ends of the two pins .
Put this on the forward side of the chain to get it lined up .
The master link is then installed from the back side .

[matthewjp14]

If I'm opening that front cover, it's getting replaced. I have opened one cylinder so its getting those head gaskets again. I do need to ensure I find the source of the knock before actually spend gasket and chain money on it though. Ordered the rotor tool over the weekend and will be heading to harbor freight for a basic puller set to combine with other hardware store fittings to make that front cover puller sometime this week.

If my hunch is correct I will be very pleased with a simple chain and tensioner replacement. Doesn't seem so ungodly expensive compared to other things on these bikes.

Such is the life of the beemer owner. 

[Bob_Roller]

Other than the alternator rotor tool, no other specialty tools are required .
Just basic hand tools .
You may want to get the oil seal that the rotor goes through if you haven't already .

[Bob_Roller]

While you have this area disassembled, you may want to upgrade the wire from the diode board to the starter .
I did this on my '87 Guzzi, it has the same charging system as the airheads, but they placed the diode board under the left side cover plenty of cooling air in this location .
I made up two new wires of heavier gauge .
There are two terminals on the diode board for output voltage .
I don't know if it makes a real world difference or not doing this, but the original wire is not a particularly large diameter wire for the 20 amp alternator .

Just another random thought, you've got access to the starter, may want to clean and lubricate it, guaranteed, it's dry of original lubricants .
I have a repair shop locally, that specializes in generator, alternator and starter repair, I remember they want $50 to this, plus replace the brushes if necessary for an extra charge .
There used to be a posting here with a video here about doing this .
I just checked, it's still here under R65 FAQ and Procedures .

[matthewjp14]

I actually have an alternator rebuild kit on hand. Couldn't get it opened up when I wanted to tackle that previously haha. Sprained a finger slipping a wrench off one of the hex nuts. I'll be investing in one of the hammer to impact bit drivers to open the philips screws holding the solenoid on because those things seem near impossible to remove in its current state.

I will be replacing the seals up front 100% If I'm in there. I'm not opening it up again to deal with that mess separately. That would be dumb.

Got the rotor tool in and popped it off quickly today. You saying once the nuts and bolts are removed that front cover can be tapped off with say a rubber mallet? That's much more enticing because I'd like to not have to spend time and money on figuring out a homemade puller to bolt onto the alternator flange.

Stay tuned.