Verify Oil Pump Flow - Top End Noise

I recently had the top end apart end on a new to me bike. After I got it back together it ran good but after running around (2200rpm) for a few min I heard a tapping noise which seemed to come from the cylinder on the spark plug side. I could be wrong but that’s where I think it is.

Starting the bike cold it’s quiet. Once it warms up the noise starts.

If I ran the bike with the intake tappet off, how much oil should I see moving around/coming out? A thought was a weak oil pump but I’m not sure if those are common failure points.

From what ive seen with the top tappet cover off, revving it slightly in neutral it usually throws a few drops of oil up onto the back side of the fender. Am guessing the throttle doesnt go over 1/4 during this test.

If you are concerned about oil flow, take off the right side head cover and remove the plug. Kick over the engine until you see oil flowing from the bottom section...once you see the oil kick it about 5 times and note how much more oil comes out. If it is at least 1/2 teaspoon, your oil pump is fine. That's spinning at about 100 rpm on kickover. Now imagine how much will come out at 1500 or 5000.

fatcaaat said:

If you are concerned about oil flow, take off the right side head cover and remove the plug. Kick over the engine until you see oil flowing from the bottom section...once you see the oil kick it about 5 times and note how much more oil comes out. If it is at least 1/2 teaspoon, your oil pump is fine. That's spinning at about 100 rpm on kickover. Now imagine how much will come out at 1500 or 5000.

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Thanks, I’ll give that a try. When I had it idle with the intake tappet cover off it threw a few small drops onto the fender.

There's an easier, if somewhat cruder, test. Once the oil pump has been primed...and it should be by now...pull the lower rocker cover, wipe it dry, reinstall it, then kick the engine over a few times. If you see oil pooled in the cover, oil is flowing as it should.

I've seen many worn out engines with oil pump problems. The problem is usually binding...due to lack of maintenance. And the problem usually manifests as worn teeth on the oil pump drive sprocket. If you verified that the pump was spinning freely during assembly and the drive shaft is correctly indexed, oil flow should be fine. If there were enough dirt to obstruct the metering orifice that controls oil flow to the top end, it would be a first.

I double checked the valve clearance, both are at .002”.

I wiggled the rocker arms side to side and found play, is this excessive? See the video below. I also measured the play with a feeler gauge and found the intake rocker to have .356mm clearance and the exhaust to have .254mm of side to side play.
https://youtu.be/5I9ME9fvdOQ

Also, when I pulled the exhaust tappet cover it had oil in it so I believe the oil pump is fine.

I doubt that you have an oil pump/oil flow problem.

That is a lot of side clearance but not what I'd consider noteworthy. It might be a contributing factor with the clacking. The rockers can be displaced laterally from cam and/or valve contact; and it can vary with temperature. It is possible to shim the rockers, using thin washers; you'll have to do some fab work...either drill-out the ID or cutting-down to OD of washer big enough to have the right ID.

New rockers, adjuster screws and valves might eliminate the lateral displacement, a.k.a. "walk" but it might take a new cam, too. The contact surfaces all develop a wear pattern, over time. It's also possible that the existing valvetrain parts will break-in again, developing new wear patterns...resulting in less "walk" and the noise going away.

As long as the cam journals, inside the head casting, are not worn to the point where the cam is rattling around, I doubt that anything will be damaged. You should look for metallic flecks (the old, dreaded, "stardust") when you change oil. A certain amount of fine sparklies is to be expected with a fresh rebuild. An abnormal amount means something is getting chewed. It's unclear to me, at this time, just how loud the noise actually is.

racerx said:

I doubt that you have an oil pump/oil flow problem.

That is a lot of side clearance but not what I'd consider noteworthy. It might be a contributing factor with the clacking. The rockers can be displaced laterally from cam and/or valve contact; and it can vary with temperature. It is possible to shim the rockers, using thin washers; you'll have to do some fab work...either drill-out the ID or cutting-down to OD of washer big enough to have the right ID.

New rockers, adjuster screws and valves might eliminate the lateral displacement, a.k.a. "walk" but it might take a new cam, too. The contact surfaces all develop a wear pattern, over time. It's also possible that the existing valvetrain parts will break-in again, developing new wear patterns...resulting in less "walk" and the noise going away.

As long as the cam journals, inside the head casting, are not worn to the point where the cam is rattling around, I doubt that anything will be damaged. You should look for metallic flecks (the old, dreaded, "stardust") when you change oil. A certain amount of fine sparklies is to be expected with a fresh rebuild. An abnormal amount means something is getting chewed. It's unclear to me, at this time, just how loud the noise actually is.

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Thanks for the information. The noise is temperature dependent and increases with RPM. I’d say it’s a ticking noise, sounds like a valve with too much clearance. When riding the bike it was loud enough for me to hear and bother me.

I drained the oil and it looked good.

I’m questioning if the rocker arm lost material allowing the clearance or if the material is gone from the head ?

I’ll check the cam shortly for play. When I had the head off the cam journals looked good and weren’t scored.

With a screwdriver to the ear the noise was the loudest on the spark plug side by the side plate.

What plug do you have in the head?

lukelaw1 said:

What plug do you have in the head?

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Unlikely as plug-to-piston contact seems to me, this is a very good point to raise...and so easy to check.

For a short-run test, the valve clearances can be set really tight. You'd never want to run with overly tight valve lash but, for a few seconds up to a couple of minutes, you could set the valves a tight as they will go while still allowing the engine to run. If the noise vanishes, or decreases, you'll at least know that it's related to the rocker arms. No difference and you'll know to look elsewhere. Do this testing with one rocker at a time. The objective is to isolate the source.

Addendum...
I've run across pistons that were noisy...and very difficult to pin them down as the source. There was a batch of aftermarket pistons that rattled like hell unless installed backward...with the sparkplug relief on the wrong side(!). That was a good 5-6 years ago, seems unlikely any of those pistons would still be sold as of this late date. Another possibility is piston-to-head, or piston-to-valve, contact. If the tolerances are just on the jagged edge, thermal expansion would account for the timing (IOW when the noise occurs) without bending/breaking something. I'd not pull the head until such time that the valvetrain has been ruled-out as the source.

Here is a photo of the cam chain. Adjusting it made no difference in noise so I ruled it out. However now I’m questioning it. There is some side to side play in each link, I’ve never had a new cam chain in my hands so I’m not sure if they have some play when new or not?

The piston is a DRATV standard bore. I used a Versah gasket kit for the first time on this build and I almost prefer the TB Parts gasket kits I’ve used in the past.

I checked and the cam and it has no play.

Did you try setting the valve lash as tight as it could go, while still allowing the valves to fully close? Remember, this is only a short-duration test procedure, you can leave the valves that tight for very long.

I've never checked a brand new cam chain for lateral deflection. And they typically are so tight, when first installed, that it's a bit unnerving. If the cam chain were slapping against the cylinder jug tunnel, it would create a lot of shiny aluminum fragments that would be all but impossible to miss while draining the oil.

As for gaskets, I've not had any real issues with any brand. Worst problem has been excessive gasket length sticking out from the case halves; 30 seconds and a single edge blade was all it took to trim that unsightly overhang.

Besides the rocker arm play and the questionable cam chain this is the only other possible thing I see (piston, see link below). If it was the cam chain I would assume the noise would be there all the time and would not be temperature dependent?

The wrist pin is tight. Not sure why the piston makes this noise unless it’s just the rings changing directions?

No mention in this post on what year engine this is, BUT that piston crown is protruding past the cylinder. You have the wrong piston... That's the noise for sure. It's very possible to damage the valves and crank in the process. Good job posting that video, it makes the diagnosis, very simple.

I have a 72 H model,I did notice the piston. came out past the cylinder then I told myself perhaps the head gasket took up the difference. I’ll measure that piston vs OEM one and report back. The valves showed no signs of contact. Perhaps I got lucky not running it much.

Here is the piston I used.

https://www.ebay.com/itm/CT70-CT-70...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

I wonder if someone swapped cranks at some point and put in a newer model with the longer stroke? Is that possible ?

You want to measure from the wrist pin, up. A pic of the old piston too.

I’ll get the dial calipers out and measure both pistons and get pictures.

Here is the box the new piston came in.

I measured both and maybe my measuring wasn’t the best since the measurements came out close but when sitting side by side it appears the new piston is taller.

I measured the cylinder from mating surface to mating surface and I get 62.64mm. It appears to be a Honda cylinder.

Thats the same piston kit i just got from Dratv for my HK0. I specified in detail short rod.

Tripod said:

Thats the same piston kit i just got from Dratv for my HK0. I specified in detail short rod.

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I’m not sure where my difference is, maybe the cylinder was machined down at some point. The piston measures close but does pushes out past the cylinder mating surface a touch.