Rocker arm and valve problem
#11
03-28-2021, 04:58 PM
Seasoned HDF Member
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Campy Roadie (03-29-2021)
#12
03-28-2021, 06:21 PM
I'm guessing English isn't your first language so I'll be nice. I'd investigate by pulling the head and the valve. It looks like it may have hit the piston and bent. That's as far as I can go without actually making you "my customer".
Tomorrow's basic 4 stroke engine lesson will include timing and interference.
Tomorrow's basic 4 stroke engine lesson will include timing and interference.
anyway, do you think is cam problem?
will remove head tomorrow
attached photo from my Harley place in Cracow Poland
Last edited by seba6250; 03-28-2021 at 06:31 PM.
#13
03-28-2021, 06:22 PM
Man... Sometimes you guys jump way to quick.... Maybe this guy in Europe is just trying to build a business... Things are not the same all around the world.. Give him a break and help him... Don't ridicule, we were all there at one time or another....
I'll have to say over revved the motor and valve to piston contact.. That looks pretty severe....
I'll have to say over revved the motor and valve to piston contact.. That looks pretty severe....
thanks for nice words!
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98hotrodfatboy (03-28-2021)
#14
03-28-2021, 06:28 PM
You're right of course.
That said, The most ethical way to learn something is on your own machine or for friend for no money. I'd help him but he clearly said he knows what the problem is, how to fix it and didn't ask for help in the first place. No matter where you are in the world, when you need help, all you really need to know are two things; who to ask for help and how to ask for it.
You're right about my attitude as well. From here on out when someone asks "Any ideas what could couse this problem?" sic, I'll just say "yes"
That said, The most ethical way to learn something is on your own machine or for friend for no money. I'd help him but he clearly said he knows what the problem is, how to fix it and didn't ask for help in the first place. No matter where you are in the world, when you need help, all you really need to know are two things; who to ask for help and how to ask for it.
You're right about my attitude as well. From here on out when someone asks "Any ideas what could couse this problem?" sic, I'll just say "yes"
thanks
Last edited by seba6250; 03-28-2021 at 06:33 PM.
#15
03-28-2021, 06:50 PM
Club Member
#16
03-28-2021, 06:57 PM
Seasoned HDF Member
Originally Posted by MURPHCC1
Pretty sure it has to do with over revving engine............
AS the revs go up and exceed the redline, the valve springs are not strong enough to keep them from floating, hence, valve contacts piston, bent valve..........
Thats how I understand it...........
AS the revs go up and exceed the redline, the valve springs are not strong enough to keep them from floating, hence, valve contacts piston, bent valve..........
Thats how I understand it...........
#17
03-28-2021, 07:03 PM
Seasoned HDF Member
Actually when a motor over revs and the springs do float the valves, what happens is the lifter pumps up all the way and when that happens that's when the valve smacks the Pistons, or should I say the Piston smacks the valve cause the valve is late to close..
OP, you didn't say if this motor's been running a while and then all of a sudden this happened or was this a fresh build and it happened right off the bat... but regardless whenever you build a motor, bigger cams, domed Pistons, shave the heads, you need to check valve piston clearance.. you need to Clay them to find out where you're at.. more information would bring it a long way as well as the motor build. Info...
OP, you didn't say if this motor's been running a while and then all of a sudden this happened or was this a fresh build and it happened right off the bat... but regardless whenever you build a motor, bigger cams, domed Pistons, shave the heads, you need to check valve piston clearance.. you need to Clay them to find out where you're at.. more information would bring it a long way as well as the motor build. Info...
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todd-67 (03-29-2021)
#18
03-28-2021, 07:21 PM
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#19
03-28-2021, 07:34 PM
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If you down shift into a lower gear and drop the clutch it will over rev the engine. Don't ask me how I know. My 1968 VW Bug engine I had to replace the pistons & valves had that problem. Was a learning experience when I was a young'in.
#20
03-28-2021, 08:15 PM
Seasoned HDF Member
You might be on to something there Max, pretty sure the shovels are 1.5 ratio rocker.. and with that high arch on the backbone, it doesn't look like a stock rocker either for a Evo or Twin cam...