79 Engine Ticking/Knocking

I'm getting ready to ride my 79 that I've been working on for years now. I've started it a few times and runs (or ran)well. I did a single carb conversion on it, so I'm running the 32dft from Stovebolt. My knowledge of carburetors is fairly limited, but I'm not sure if a poorly tuned carb can cause this ticking/knocking or not. It ran several times just fine with no problems previously but I suspect my son may have "adjusted" the idle fuel mixture for me when he was in the shop with me the other day. I rev'd it up a few times while it was warm, and then suddenly started making this sound as it sat on the side stand. It does this both on side/center stand and before/after an oil change. I currently have a new filter, Rotella-T 15W-40, and 6oz seafoam in the crank case. I ran it today for about 5-10 mins, long enough to get the fan to come on, and it didn't seem to impact the sound one way or the other.

When I changed the oil I got a lot of black sludge out (it's been sitting 5 years). I'm not sure how prone the oil passages in these engines are to getting "plugged up", either. I basically have a lot of guesses as to what this could be, but I'm looking for a professional opinion.. or at least more educated speculation.

I haven't changed the belts yet, but was going to this week.


[video]https://youtu.be/_x2x6Xst0a0[/video]

its time to take the timing belt covers off and valve covers off ..and check for belt tension and timed right plus you can turn it by hand with crank bolt and see if you ca find whats making the noise...i dont think it lower motor but could be i think its i valve trane somewhere.....its certainly not the carb ...check oil in motor for its condition ....

Sounds like rattle for sure. Might want to remove the valve covers and check for stuck valves. Doesn't sound carb related to me.

That sounds like a valve tapping a piston.
One tooth off on the belt can cause this.

Broken rocker? Lots of things that can cause that noise. Do like suggested and pop the covers and investigate. It could even be a valve adjuster that didn't get tightened properly.

yep time to go slow here and check this out good ..with plugs out an timing covers off you can check all this by hand ...as resistance will be low and be able to feel things good ..jumped timing is huge possible as dan said

better find the trouble real quick. Rubber mallet thump the valves and check the timing real close.

For sure check the timing belt time and valves , Maybe want to check the sump screen under the right lower engine seeming how that oil was so bad...Hope it wasn't starved for oil.

Thanks everyone. I'll be doing the timing belts this week and will report back!

Hey Folks.

I pulled the valve covers, timing belt covers, flywheel timing cover, spark plugs, generator cover, and followed the valve adjustment procedure in the manual, and valve/tappet clearances were good. I made some very minor adjustments to a couple of the valves (corrected by turning two of the adjustment screws just slightly, less than 1/8th of a turn). I found some small metal (aluminum) shavings in the oil, predominantly on the intake valve springs on the left side (Cylinders 2 and 4). I'm assuming the shavings are from whatever is causing the noise, however I will note that I have fresh oil AND about 6oz of SeaFoam in the crank case. I suspect the only other source of the shavings could be from whatever the seafoam knocked loose. (possibly from a previous issue one of the PO's had?)

The timing marks line up perfectly between the crankshaft pulley, and the timing gears both on the left, and right sides, so it doesn't appear that the timing belt jumped. The belts look to be brand new. My dad was the PO and is about 90% sure he changed the timing belts prior to parking the bike about 5 years ago. The condition of the belts basically confirms that. The belt teeth look new, and don't show any signs of wear, as described/shown in the shop manual. (Regardless, i'll change them anyway due to age.)

The timing belt for the valves on cylinders 1 and 3 (Right side as you're sitting on the bike) is loose.. Loose enough that I can turn the tensioner pulley freely with very little effort. It is TOUCHING the timing belt, but the belt isn't tight enough to keep the pulley from rotating. The opposite timing belt for 2 and 4 (Left side as you're sitting on the bike) is tighter (not over tight), and I'm unable to turn the pulley without using a fair amt of force. NGW's Shop Talk Section has an article by Octane that outlines the procedure for changing the timing belts and describes this issue, as well as outlines the procedure for correcting the slack on the right belt.

My question is:
Could this sound be caused by a loose timing belt, even if the belts indicate correct positioning, and the valve clearances are correct? Any ideas or things I can try would be greatly appreciated.

Thank you!

In my opinion only, if the timing belt is loose it will throw off the timing of the valves. The belt may be in the correct position for the teeth lining up when stopped, but under a load (such as increasing your throttle) the belt will be pulled further than it should which is nearly equivalent to be off 1 tooth on the belt.

Listening to your video seems to confirm that. I would suggest tightening the tensioner correctly first and then check your timing marks. It is possible that the noise could be removed with correctly set belt tension (assuming no valve damage).

Well the bad is the metal shavings in the crankcase, thats not good, might have a bad rod bearing.

Get the belts adjusted. That could be the whole problem, hopefully. Five year old belts that just sat are questionable at best. They take a set, sitting in the one spot for so long. Five years is the recommended interval driven or not. My guess is the 1-3 is off a tooth. If so, it may have bent some valves. Adjust the belts, turn over by hand listening closely. If it starts and runs good, you dodged one. If not, I would check compression next.

Hey guys, I've been sick the last few weeks. Some kinda nasty flu has been making it's way through the family. I did a valve adjustment. And loosened the tensioner pulleys and it pulled a decent amt of slack out of the belts. I'll be replacing them this week. I started it and it knocked until I revved it up to about 5k and the knocking is gone. I've shut it off and restarted it several times and it's no longer knocking. Should I chalk it up to belts/timing issues or is this perhaps a sign of an oil pump on the way out? Thoughts?

I dont think your problem has anything to do with the oil pump, Change the belts and see if it cures the problem.Make absolutely sure the belts are in time, turn the engine with the front crank bolt over a few complete revolutions and triple check the marks on the cams and crank before you fire it up.
Glad your over the flu..those really suck.