Very Interesting Post-Mortem Result
#1
Very Interesting Post-Mortem Result
I'll start at the beginning. Last week, my bike was making a very light "tick tick" noise. To me it sounded like something in the valvetrain was making noise, maybe hitting once every time the cam came around. A friend of mine, more experienced with engines, told me that he thought the noise was actually a crack/leak in the exhaust manifold, and the ticking noise was actually the sound of escaping detonation noises. But either way, we both agreed I had to keep riding and wait for it to get worse before diagnosing -- there just wasn't enough to go on.
Well, today it "got worse". It started making an awful clattering noise upwards of 3k RPM and it was losing power. Since it was losing power-- not a tiny exhaust leak. Anyway, I tore it down in record time to see what was the matter. Once I had both camshafts off, I noticed that one of the exhaust valves (2nd from the left, I believe) was sitting way too high. When I pushed on the cap, it moved easily. Hmmmm.
It turned out that the tappets had failed. This caused the valve to no longer be pulled back up by the spring, and instead be pushed up by the piston. Below is the "pancaked" tappets and valve (which is slightly bent).
Here's the damage to the piston. It basically shined up the top surface, but the geometry does not seem to have changed much. I'm not replacing the piston because of this.
So as I mentioned, I AM IN NEED OF AN EXHAUST VALVE AND TAPPET. If you have one you can sell me, I will buy it. Otherwise, I'll have to pay $55 for the valve and $14 for the tappets. On top of the head gasket I already have to buy. Then I'll also need to devise a way to compress the springs in order to install the tappets onto the valve.
Another question, please. If I am forced to buy a valve and tappet from BikeBandit, they sell many different tappets. Apparently they come in different sizes, from "1.200" to "2.875." What is this for, and which would I buy? Thanks for your help, everyone.
Well, today it "got worse". It started making an awful clattering noise upwards of 3k RPM and it was losing power. Since it was losing power-- not a tiny exhaust leak. Anyway, I tore it down in record time to see what was the matter. Once I had both camshafts off, I noticed that one of the exhaust valves (2nd from the left, I believe) was sitting way too high. When I pushed on the cap, it moved easily. Hmmmm.
It turned out that the tappets had failed. This caused the valve to no longer be pulled back up by the spring, and instead be pushed up by the piston. Below is the "pancaked" tappets and valve (which is slightly bent).
Here's the damage to the piston. It basically shined up the top surface, but the geometry does not seem to have changed much. I'm not replacing the piston because of this.
So as I mentioned, I AM IN NEED OF AN EXHAUST VALVE AND TAPPET. If you have one you can sell me, I will buy it. Otherwise, I'll have to pay $55 for the valve and $14 for the tappets. On top of the head gasket I already have to buy. Then I'll also need to devise a way to compress the springs in order to install the tappets onto the valve.
Another question, please. If I am forced to buy a valve and tappet from BikeBandit, they sell many different tappets. Apparently they come in different sizes, from "1.200" to "2.875." What is this for, and which would I buy? Thanks for your help, everyone.
#4
Supposed to be a one time use, same with any other gasket. When you tighten up the bolts you "crush" the gasket, and if you go to put it together a second time with the same gasket it will not be likely that you will line it up the same way that it was installed the first time.
#8
#9
Engine only has 15k on it, which is why I'd like to keep everything intact if possible. I had not checked the valve clearances prior to the incident, but in general I never had any problems or noise coming from that area. When I install the new valve though I'll let you know whether all the other valves' lash are in spec.