So this is my problem: I checked my valve clearance and adjusted accordingly over the weekend, rocker arm type. Three of the four are fine and stay in adjustment. The fourth, my right hand exhaust valve move out of adjustment when i turn the engine over after i set the clearance. Why???
I found that when i checked this valve first time it was quite tight. I adjusted in to within spec (0.12mm +- 0.02) and covered the valve caps, put the fuel tank back on etc and fired him up. There was a loud knocking sound coming form the engine which didn't sound good.
I let the bike cool overnight and rechecked the valves. All were fine except the RH exhaust valve. There was so much slack in there i could easily move it up and down with my finger. I reset the clearance, lock the nut, turn the engine over and then the valve is stuck closed. Not even a 0.05 feeler gauge goes in. I repeat the process only to find that when i turned the engine over this time there is loads of slack in the rocker arm again. WHY??? Readjust, turn over, valve is tight. Readjust, turn over, slack, etc.
It's a Honda XR400R, kick start. So i use the kick starter to find TDC on compression. I kick it through a few times watching the valves open and close, listening for intake, wait for the intake valves to close, kick through slowly to let the compression build, and when there's a notch in the pressure on the kick starter i have TDC, right before the exhaust valves open. Right? Works for kicking the beast into life...
So i open up the timing inspection cap on the LH side of the engine cover and check if i am indeed at TDC. Turns out I am not. The TDC mark on the flywheel appears right after the exhaust valves opened and closed again. I am no mech, but i have read up a bit on the basics of a four stroke and this does not seems right.
Just before i serviced i did hear some valve noise, not much but audible, like a happy tappet. But this is strange... Did the rocker arm bend? Did i bend a valve? How does one check for this? Do i have timing issues? Compression? Any other suspicions?
There is a guy in Walvis that does XR's, but i haven't been able to reach him...
Any advice?
Ahoy
I found that when i checked this valve first time it was quite tight. I adjusted in to within spec (0.12mm +- 0.02) and covered the valve caps, put the fuel tank back on etc and fired him up. There was a loud knocking sound coming form the engine which didn't sound good.
I let the bike cool overnight and rechecked the valves. All were fine except the RH exhaust valve. There was so much slack in there i could easily move it up and down with my finger. I reset the clearance, lock the nut, turn the engine over and then the valve is stuck closed. Not even a 0.05 feeler gauge goes in. I repeat the process only to find that when i turned the engine over this time there is loads of slack in the rocker arm again. WHY??? Readjust, turn over, valve is tight. Readjust, turn over, slack, etc.
It's a Honda XR400R, kick start. So i use the kick starter to find TDC on compression. I kick it through a few times watching the valves open and close, listening for intake, wait for the intake valves to close, kick through slowly to let the compression build, and when there's a notch in the pressure on the kick starter i have TDC, right before the exhaust valves open. Right? Works for kicking the beast into life...
So i open up the timing inspection cap on the LH side of the engine cover and check if i am indeed at TDC. Turns out I am not. The TDC mark on the flywheel appears right after the exhaust valves opened and closed again. I am no mech, but i have read up a bit on the basics of a four stroke and this does not seems right.
Just before i serviced i did hear some valve noise, not much but audible, like a happy tappet. But this is strange... Did the rocker arm bend? Did i bend a valve? How does one check for this? Do i have timing issues? Compression? Any other suspicions?
There is a guy in Walvis that does XR's, but i haven't been able to reach him...
Any advice?
Ahoy
