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Author Topic: Over revved the $h!+ out of her :(  (Read 3514 times)

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Offline Greenducky55

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Over revved the $h!+ out of her :(
« on: April 11, 2013, 12:57:22 PM »
So last night was riding with my buddy we both decided to get on it good since neither of use really have since we got our bikes togeather. Was at about 6800-7000 rpm in 4th gear when she popped out of gear.... So as you can imagine revs went to the roof never really seen how high but once she came down I then hear the valve train really loud though my helmet. Was able to limp 2 miles home and park her. But have not been able to asses the damage. I'm expecting possibly a bent valve? I'm hoping my pistons arnt damaged supposed to ride to the coast Sunday. I'm hoping to just swap my k3 head onto my k1 with my k1 cam hopefully all goes well. Any ideas? I have an extra 836 head gasket and valve cover gasket.
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline lucky

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Re: Over revved the $h!+ out of her :(
« Reply #1 on: April 11, 2013, 01:00:18 PM »
Just wait and see.
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Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #2 on: April 11, 2013, 01:02:58 PM »
Ya pretty much where I'm at.
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline ekpent

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Re: Over revved the $h!+ out of her :(
« Reply #3 on: April 11, 2013, 01:18:32 PM »
Pull the inspection caps and check the valve tappets etc. before doing a teardown. Maybe you got lucky and just spun an adjuster nut loose and is tapping the cap. That 836 though adds another dimension with its more power etc.  Good luck,hopefully not fatal.
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Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #4 on: April 11, 2013, 01:31:07 PM »
Ya ill have to check I did just recently adjust the valves too and I don't remember being very aggressive with tightening. But well see I hate that I'm stuck at work for another 6 hours still
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Over revved the $h!+ out of her :(
« Reply #5 on: April 11, 2013, 01:36:09 PM »
If it's noisy and not running right my guess would be a bent valve hopefully without damage to the piston when it hit. If it's this bad it's locked up. Missed 1 to 2 at WFO.

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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline ekpent

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Re: Over revved the $h!+ out of her :(
« Reply #6 on: April 11, 2013, 01:39:32 PM »
That piston needs to go in the Hall of Fame Jerry. It is so bad its almost pretty. Thing is totally hammered.
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Offline 70CB750

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Re: Over revved the $h!+ out of her :(
« Reply #7 on: April 11, 2013, 02:12:50 PM »
Quote from: Jerry Rxman Griffin on April 11, 2013, 01:36:09 PM
If it's noisy and not running right my guess would be a bent valve hopefully without damage to the piston when it hit. If it's this bad it's locked up. Missed 1 to 2 at WFO.



$HIT!  Took me a while to realize what I am looking at.  What a picture, Jerry.  I hope I never see it myself.
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Offline Bailgang

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Re: Over revved the $h!+ out of her :(
« Reply #8 on: April 11, 2013, 02:13:49 PM »
That piston looks just like the one in the 750F engine from a parts bike I picked up years ago. I knew I was in for a treat when I removed the valve cover and saw the #1 int valve was nowhere to be seen.
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Offline flybox1

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Re: Over revved the $h!+ out of her :(
« Reply #9 on: April 11, 2013, 02:31:06 PM »
Quote from: Jerry Rxman Griffin on April 11, 2013, 01:36:09 PM
If it's noisy and not running right my guess would be a bent valve hopefully without damage to the piston when it hit. If it's this bad it's locked up. Missed 1 to 2 at WFO.


:o that deserves its own lighted case in the man cave  8)
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Offline Roach Carver

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Re: Over revved the $h!+ out of her :(
« Reply #10 on: April 11, 2013, 03:48:39 PM »
Like was said. Check your valves. Ive done the exact same thing and all i had to do was adjust the valves. This is a common occurence. Fingers crossed for you.
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Offline Greggo

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Re: Over revved the $h!+ out of her :(
« Reply #11 on: April 11, 2013, 03:53:39 PM »
Quote from: roach carver on April 11, 2013, 03:48:39 PM
Like was said. Check your valves. Ive done the exact same thing and all i had to do was adjust the valves. This is a common occurence. Fingers crossed for you.

+1
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Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #12 on: April 11, 2013, 04:00:19 PM »
Thanks guys. And holly hell I'm pretty sure it's not like that lol. That's a great paper weight lol.
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline Garage_guy_chris

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Re: Over revved the $h!+ out of her :(
« Reply #13 on: April 11, 2013, 05:10:27 PM »
M'mmm aluminum donut. 



That is one hell of a piston failure, never seen one like that before, i have a CB450 piston that burned a 1/2" hole right thru the center
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Offline scottly

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Re: Over revved the $h!+ out of her :(
« Reply #14 on: April 11, 2013, 05:46:35 PM »
Quote from: roach carver on April 11, 2013, 03:48:39 PM
Like was said. Check your valves. Ive done the exact same thing and all i had to do was adjust the valves. This is a common occurence. Fingers crossed for you.
2+ When it happened to me, the top half of an adjuster screw snapped off. I found the broken piece with the lock-nut still attached after removing the cam cover.
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Offline madScientist

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Re: Over revved the $h!+ out of her :(
« Reply #15 on: April 11, 2013, 06:13:54 PM »
That piston is epic!

I wasnt sure what the reference was until i saw the wrist from the rod.
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http://forums.sohc4.net/index.php?topic=113293.0
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Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #16 on: April 11, 2013, 11:04:47 PM »
Found the problem lock but rattled off and adjuster was allthe way backed out. Haven't found the but yet gonna pull the valve cover Tomarrow and find her. So glad that's all she had wrong. Meet to clean up the tip of the valve though.
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Over revved the $h!+ out of her :(
« Reply #17 on: April 11, 2013, 11:23:03 PM »
I'd say you are one LuckyDucky
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline ekpent

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Re: Over revved the $h!+ out of her :(
« Reply #18 on: April 12, 2013, 04:31:26 AM »
Do you have to pull the engine or are you lucky enouph to have a frame kit ?  Good reminder for all to snug those locknuts up well    ;)
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Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #19 on: April 12, 2013, 04:52:59 AM »
Actually don't have a frame kit yet but gonna build a relatively simple one tomarrow
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline bjbuchanan

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Re: Over revved the $h!+ out of her :(
« Reply #20 on: April 12, 2013, 05:17:12 AM »
I did the same thing 2 weeks ago but my adjuster nut was hanging on by a half thread just gmering away the tappet cover. Why don't you stick a magnet in there instead of all that extra work
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Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #21 on: April 12, 2013, 08:09:47 AM »
cant even see the nut anywhere in there is the problem. plus im tired of my valve cover gasket leak lol.
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #22 on: April 12, 2013, 05:58:16 PM »
My home made frame kit. I still need to clean it up and paint everything but gonna work out damn good I believe
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.

Offline Jerry Rxman Griffin aka MuthaF'er

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Re: Over revved the $h!+ out of her :(
« Reply #23 on: April 12, 2013, 06:02:09 PM »
Did you pull the oil pan yet?
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As of today 3/13/2012 my original owner 75 CB750F has made it through 3 wives, er EX-wives. Free at last.  ;-)

Offline Greenducky55

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Re: Over revved the $h!+ out of her :(
« Reply #24 on: April 12, 2013, 08:22:04 PM »
I pulled the vale cover and found the nut while I was in there I retorqued my head an everything
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1975 cb750f1 with k1 motor 836cc stock cam, pamco ignition.
1973 cb750k digger project
2008 ktm 450sxf, 2005 yamaha yz250 2 stroke, 2001 ttr125l modded pit bike.
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