1978 XS650 Engine knocking noise

[livetoride21]

Hi Everyone, I have a 1978 XS650 that I just brought back to live after being stored away for 31 years. It was stored away after the owner ran the bike low in oil, and then heard a knocking noise the next day.

What a surprise, I have a strange tick/knocking noise. I'm afraid it could be a rod bearing, any ideas?
I adjusted the cam chain tensioner and it appears to be adjusted fine now, but could it still be cooked on the inside?
Also could the valves being out of adjustment do this? (I'm going to check them tomorrow)
lastly, I've checked and have very good compression 150lbs, so I'd be surprised if there is any engine damage in the bottom end without in turn damaging the cylinder walls or valves.
In my experience, when a motor runs low in oil, the first thing to go are valves / compression. then crank.

 

[NONclow]

Welcome! Invest in a mechanics stethoscope. It'll help pinpoint the noise. It sounds like valves to me tho. Not that it can't be scuffed cyl walls, or loose wrist pin(s), or pitted valve stems, or.........

Time to play doctor. Just don't forget the hot nurse!

 

[peanut]

sounds like top end noise to me ...probably the front cam chain guide is severely worn or has had the rubber ripped out of the guide and the chain is running on the aluminium holder.

If you had a USB endoscope/boroscope you might be able to see the front guide without a strip down by removing the chain tensioner assembly and feeding the scope into the tensioner opening.

to be frank if its not been worked on and run for 30 years the whole bike is going to need some serious overhauling and renovation including an engine rebuild.

 

[retiredgentleman]

The camchain tensioner has a "damper" on it. You should remove the tensioner and confirm that the damper is still there and in good condition.

 

[livetoride21]

Thank you for the comments guys! I was leaning towards top end noise as well.
The bottom end on these bikes is pretty stout, and as I said before I have very good compression, so I'm trying to avoid a complete tear down if I don't have-to.
I'm going to check the valve clearances today, and check the tensioner, as well as make sure there's nothing rattling around in the clutch/starter. if I can't get the ticking to go away after that I'll pull the engine and start looking at the guides.

 

[livetoride21]

The camchain tensioner has a "damper" on it. You should remove the tensioner and confirm that the damper is still there and in good condition.

Which part is the "Damper" in the chain tensioner assembly?
do you have a picture by any chance?

 

[peanut]

Thank you for the comments guys! I was leaning towards top end noise as well.
The bottom end on these bikes is pretty stout, and as I said before I have very good compression, so I'm trying to avoid a complete tear down if I don't have-to.
I'm going to check the valve clearances today, and check the tensioner, as well as make sure there's nothing rattling around in the clutch/starter. if I can't get the ticking to go away after that I'll pull the engine and start looking at the guides.

if you are going to set the tappet clearance I would suggest you use the settings for the early XS650 engines of 0.006 intake and 0.012 exhaust .

There are numerous advantages to using these settings. have a read of this technical article by Brit XS650 specialist Howard Smedhurst , I expect you'll find it as enlightening as I did .
http://www.smedspeed.co.uk/tech.html

cam chain tensioner assembly images
https://www.google.co.uk/#q=xs650+cam+chain+tensioner+image

 

[retiredgentleman]

Which part is the "Damper" in the chain tensioner assembly?
do you have a picture by any chance?

https://www.mikesxs.net/products-26.html#products

 

[5twins]

The "dampener" is nothing more than a copper washer on the plunger between the head and the adjuster screw. You probably noticed during your adjustment that the plunger bounces in and out. It's head sometimes bangs into the back of the adjusting screw. This copper washer dampens and quiets that blow. Without it, you can get a ticking like loose valves. Pull the adjuster screw, plunger, and spring right out of the housing. Don't worry, no loose parts will fall down inside the motor or anything. Check the assembly for the washer .....

The '78 spec for the intake valves is .004". That can be too much. My '78 ticked like crazy using it. Most of us run .003" on the intakes. I know .001" doesn't seem like much, but it quieted mine right down.

 

[gggGary]

Good poop from smedspeed! I guess I was aware of tighter lash for reduced noise but those advantages of running the valves "loose" were news for me. Some experimenting seems in order.

 

[gggGary]

An odd idea comes to mind, I may run it by 2M.

 

[TwoManyXS1Bs]

Finally got to listen to your youtube video. The 'clatter' sound is synchronized with the exhaust note, which means it's synchronized with the camshaft, and rockers. If oil starvation is suspect, there's a good chance that there's a ground-down cam lobe and/or rocker's follower pad. Or more.

The 'ting', 'ting' sound at engine shutdown also is a clue to a rocker.

Hopefully, it's just valve lash needing adjustment. With the valve covers removed, flashlight around in there to see what you can of the camshaft lobes, and note any discoloration and scarring.

Good poop from smedspeed! I guess I was aware of tighter lash for reduced noise but those advantages of running the valves "loose" were news for me. Some experimenting seems in order.

Yeah, I like smedspeed. He writes the way I think. Agree with his stuff.

If I run my XS1B at the 'early' lash spec of 0.006" and 0.012", it runs much crisper.
And has the telltale 'clatter' of a racing Husqvarna. (The noisier they are, the faster they go)

I've closed mine down to 0.003" and 0.006", per the bulletin, and it took out a lot of the clatter, and the performance. I'll probably open them up a little, later.

An odd idea comes to mind, I may run it by 2M.

Uh-oh.

(Welcome back, BTW)...

 

[5twins]

I've been aware of the larger clearance benefits for some time. It was explained on this 650Motorcyles.com page a long time ago. It says pretty much exactly what the smedspeed link does .....

http://www.650motorcycles.com/isky.html

Once I had supposedly quieter running elephants feet adjuster screws installed, I decided to try it. Honestly, I really didn't notice any performance gains, the valves just made more noise. Yes, you can make the elephants feet adjusters noisy if you go big enough on the clearances, lol.

But, reading it again now, I may just start tweaking some more. The big benefit here seems to be making the intakes bigger so you can reclaim some of that lost "linger" time. The exhaust is already bigger so I'm thinking it doesn't suffer from the problem as much. I did go back to .004" on the intakes with the elephants feet because they will run that nice and quiet. Maybe I'll bump them up a little, say .006" IN and .007" or .008" EX.

But, one thing you do notice with the elephants foot adjusters is that when you go to set them, you usually find the foot portion stuck to the valve top due to oil cling. This would seem to indicate that all the lash movement is taking place in the ball and socket part of the screw. Making the lash too big might start yanking the foot off the valve top all the time and possibly accelerate the wear between the ball and foot. The .006" setting on the exhausts seems fine but maybe up near .012" won't be. So, that's why I'm thinking maybe 6 and 7 or 8. Or maybe I'll start with 6 and 6.

 

[TwoManyXS1Bs]

5Twins, which brand of elephants foot adjusters are you running? I found the CB adjuster cups to be somewhat brittle, and some in the VW community reported them shattering. Just a thought concerning clearances...

 

[5twins]

I have the cheapie EMPI ones but on the about half dozen motors I've put them in, there have been no problems to date. I do plan on using the little better ones (supposedly) from now on, the Bugpack ones .....

http://vwparts.aircooled.net/Elephant-s-Feet-Valve-Adjusters-8-p/adj-elephants-ft-8.htm

I feel this upgrade is a no-brainer. Heck, 4 screws for around $20 is lots cheaper than the $30+ for repops from Mike's.

 

[gggGary]

5t you got me, I ordered 2 sets of elephant feet, like I don't already HAVE elephant feet. now to decide which engine gets those and which gets the special ground 2m set................

 

[TwoManyXS1Bs]

I have the cheapie EMPI ones but on the about half dozen motors I've put them in, there have been no problems to date.

I didn't find any signs of brittleness with the EMPI.

I do plan on using the little better ones (supposedly) from now on, the Bugpack ones .....

http://vwparts.aircooled.net/Elephant-s-Feet-Valve-Adjusters-8-p/adj-elephants-ft-8.htm

Oh, yes, those look like the better Porche adjusters, as shown in 270Yam's thread:

http://www.xs650.com/forum/showthread.php?t=32559

 

[5twins]

I find this mod much easier to do now that I have started grinding into the bottoms of the rockers with a rounded stone in a die grinder as oposed to grinding the whole bottom flat. You don't have to remove the rockers from the head this way, just wrap them good with a rag to keep the grinding grit out .....

 

[livetoride21]

thanks for the replies guys, I adjusted the valves to 0.003 intake and .006 exhaust, and it has quieted down a bit. it still seems louder than I'd expect it to be though. I checked the cam lobes and everything looks pretty pristine, not rounded or anything concerning.
I also checked the damper and its still there and in decent shape. I'm figuring now that maybe it could be the plastic guides causing this noise?
I know for-sure some of this noise is coming from the rockers, as when I was adjusting the clearances I rocked it back and forth and got the exact same sound.
I'm at the point where I'm temped to pull the engine out and give it a once over.
any thoughts? Am I overreacting at a 30+ year old bike having valve train noise?

 

[retiredgentleman]

thanks for the replies guys, I adjusted the valves to 0.003 intake and .006 exhaust, and it has quieted down a bit. it still seems louder than I'd expect it to be though. I checked the cam lobes and everything looks pretty pristine, not rounded or anything concerning.
I also checked the damper and its still there and in decent shape. I'm figuring now that maybe it could be the plastic guides causing this noise?
I know for-sure some of this noise is coming from the rockers, as when I was adjusting the clearances I rocked it back and forth and got the exact same sound.
I'm at the point where I'm temped to pull the engine out and give it a once over.
any thoughts? Am I overreacting at a 30+ year old bike having valve train noise?

What oil grade are you using? These engines are noisy compared to modern engines, so you may just have to get used to it. 20W 50 is the best oil to use, as it reduces the ticking somewhat. I would say its better to ride the bike for a while, before jumping into a re-build.

If you want a super smooth and quiet engine, these are the wrong bike for sure.