Top end clatter noise

[Fordiesel69]

This is a Suzuki 2011 TU250X motorcycle and I checked the valve lash. It is perfectly dead on.

Here is the video of the top end clatter, ignore the knocking sound you also hear, that is the balancer knock deep down in the bottom of the engine that all of these do since they are new . I am talking the tapping noise. In looking on ebay and cylinder heads I am not sure where this noise could be coming from. Like cam chain, rocker arms, etc? I guess it could be a piston skirt or such but to me this really sounds like the very top of the motor like valves and cam.

Here is a photo of the cylinder head and valve train (not mine, just one from the internet):

Video Here:

 

[samven]

Do you have a mechanics stethoscope, You might be able to isolate exactly where the tap is. It sounds like valves but it could be chain tension. Does it go away when warm or get worse. In this motor the tap seems to be in perfect sync with the exhaust note not rattling.

 

[Fordiesel69]

I do not but I used a long scewdriver and the sound is at the top most of the engine where the cam and valve rockers are.

I am just at a loss as these engines are bullet proof and do not make enough power to harm themselves. The rockers and how you set the lash adjustment is also very robust. Unless of course a partially broken valve spring.

 

[Fordiesel69]

UPDATE

Problem is diagnosed but unfortunately will never be solved. The camshaft appears to have been unfinished from the factory as if it came out of the forging furnace untouched. It's black and very very rough textured and does not appear to be hardened. It ate up the rockers pretty bad.

 

[Fordiesel69]

Is this an oil related failure (lack of moly or zinc) or does this appear more of a metalurgy issue during manufacturing?

Yamaha had this issue in 2010 or so with their XV1900 roadliner / stratoliner bikes.

 

[samven]

Great, dont tell me this, I have a 2008 xv1900 and there is no way to work on this motor it is so crammed in and a support part of the frame.

 

[Fordiesel69]

does my cam look like oil related failure or factory finish deffect?

 

[Fordiesel69]

Anyone?

 

[Fordiesel69]

Really? Nobody wants to comment on the wear pattern?

 

[Fordiesel69]

Update.

I installed missing parts to make the bike road worthy and did a 25 mile test ride with no failures, there was oil seeping out of the seams where I did not reseal the rocker cover. So it must be getting some oil. I want to beleive this is just a manufacturing defect with the cam surface. But I wonder if any of these 3 scenarios are a possibility.

1. Wrong oil was used that was not suitable for flat tappers.
2. The excessive high idle and slow engine rpm from the rider course starved the top end. After all 4675 miles is a lot when you consider a parking lot plus all idle and start / stop cycles.
3. The cam lobes may have not been machined properly as if you look at even the base circle there is a rough finish. This area has not load so it should not wear much. The lobes are also gallled.
3B. Maybe the rocker pawls peeled or wore in a way it ate the cam, but I think it was the other way.

 

[Exhaustgases]

Photos? Most of us likely have no idea what we are looking at. Looks like the cam was removed. Then show us the pics of just the cam and use something as a pointer to point things out. You didn't show us much as far as the whole lobe.
It looks like the one base circle is either over heated or rust? Removing the cam and cleaning it then pics would have been nice.
Looking at those followers and the wear, pretty much destroys all the contact surfaces so can't determine if some part originally had a bad finish. And if it was over heated during the wear process, messes up trying to get the parts tested for hardness.

 

[Fordiesel69]

Exhaustgases,

Photos in post #4. Very high quality and you can zoom. Look at cam lobes, and you will see a dark grey roughness like it was forged rough.

I stopped by a local shop and they had a theory. Being a former MSF course bike, it most likely saw significant idle time. The mechanic does not know the TU250X and has only read about them, but claims that other models of suzukis use a non chrome plated cam, and instead use a hard chrome rocker pawl. The cam is techincally the softer of the two surfaces. His best guess is that instead of being run low on oil that the high idle time wore thru the hard chrome on the rocket pawls, and dug into the cam lobes. The wear continued to accelerate on both parts.

Alternately, my thought is because these are often stored in out buildings with no heat, the camshaft have have gotten flash rust in the spring during the thaw, and once the cam surface get rusted, it damaged the rocker pawls.

These are just theories.

 

[Fordiesel69]

I tore down the top cam cover of my 1700 mile bike for inspection purposed and the cam and rocker pawls look mint.

 

[Fordiesel69]

UPDATE:

I purchased a very nice 1900 mile used top end that is mint. I will sell the head and hardware minus the cam and rockers. The seller would not break it up in piece parts.

Before I ordered it I removed the two valve adjustment caps and ran the engine, with a flashlight shined in the hole there is oil spraying all over in there, and oil flys out both inspection holes, so no issues with oil supply. We can rule out oil starvation as a cause.

The failure must be from the zillions of idle hours, combined with the many stop / start cycles. Coupled with the bikes not moving faster enough to cool down. The oil most likely was too hot or wrong type was used.

Ended up inspecting all my other 3 bikes and one more was on the verge of failing, the other two looked brand new. The one I caught in time, the rockers are peeling and just started scratching into the cam. Engine is mint and clean inside. I should be able to polish the cam by hand and the new rockers should solve any issues in the future.