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· i love lamp
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4,153 Posts
Discussion Starter · #1 ·
so my head was taken off today and found out that i dropped a valve. luckily, all that happened is that my piston just slapped that valve a bunch of times and didn't actually fall into the cylinder. so, i'm putting in some new JE pistons, thinner head gasket, degree the cams, and i'm upgrading to a full exhaust. afterwards i'll get it dyno tuned. so this should add a few extra ponies.:jump here a some pics





this is a pic of the spring retainer cracked in half




the head


the valve




piston



head
 

· i love lamp
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4,153 Posts
Discussion Starter · #3 ·

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241 Posts
I dropped a valve in my 05 too and did some damage. The valve dropped and just "kissed" the piston. The intake valve bent a bit but did not do any head damage (besides this valve and the valve guide). I ended up replacing the piston anyway because i was afraid it may have weakened it, plus the engine was out anyway and it was cheap. I wanted to get my cams "degreed" too and the guy told me that they were already set at 105/105. He told me that that is right on the money, is he right? What does degree the cams mean? I hope he was right when he said that the current 105/105 is the best for me? He also cleaned up all the carbon and then "cut" the valves to ensure a good seal. I hope this was enough.
 

· Forum Moderator
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How did it happen?
 

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Im not sure how it happened to the other guys, but mine was apparently from over-reving for too long a time, then suddenly drop in RPM's. From what I hear, these yamaha engines have a history of dropping valves because of keepers failing. I was on a road (no one around so dont bash me), doing a long wheelie in high rpm. For some reason this day felt "good" for me because the front end just managed to stay up soo much longer than it normally did. I was very high in rpms and when I let the front end down and slowed down quickly (to turn on my street), it suddenly felt as if I took one of my spark plug wires off. After taking motor apart, I noticed that the keeper let go and dropped the valve into the cylinder causing some damage. I have done ALOT of research, and apparently the original yamaha keepers are junk and are prone to fail in these types of conditions. I was advised to change them all when I put it back together, rather than just repairing the one. I of course did just that so that I do not run the risk of dropping another valve later. Kinda scary how a $1 part can cause $2000 damage?
 

· Ghostrider Squadron
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9,259 Posts
make sure and hone out and clean up head where bucket goes. looks like it got little scarred up. nothing that cant be fixed.

really no point in milling head and running thinner gasket.. unless ur trying to get to certain squish number. but clearances just wont allow much. stock headgasket is .020 thick. split it and its .010. YEC gasket thats not findable now is like $150 and it measures .012 i think. plus new stock gasket is cheap..but i always reuse old one anyways when i split it. it is worth little gain and worth doing. glad u caught it man. it could have turned ugly.


now let me know when u put pistons in. ill tell u thats mother!!!! not much room if u put rings and pistons into cylinders and then slide them onto motor, and jsut put in pins and circlips. its major pain to do. be careful with those damn circlips... dropped one in motor 3 times last time i put on cylinders. had to take off pistons, take off cylinder, and then put all pistons back in cylinder, then put cylinder on motor and try with circlips again. tried stuffing papertowel in to stop circlips..but there jsut not enuff room once u get 2 middle ones done and working on 2 outer pistons.
 

· AFTERHELLBURNER
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1,729 Posts
I think i'm easy on bikes scheduled mait. no wheelie-burnout-dragrace but i do like long high speed sweepers. Both my 00 & 06 "blowed-up" in the same corner 00 spun a rod bearing 06 dropped valve. For the 06 I was in said corner leaned over maybe 3inch from touching knee 100mph and the rear felt like it was sliding and did'nt seem to want to rev past 10 grand. Once I stood the bike up it started clakin like the chain broke engine cuts out and I coast to a stop. I look back chains their " NO F**KIN WAY " I babied that bike during "break in period" I really was'nt pushing it after the 1000 miles or whatever it is anyway because of the shit stock tires. If I do start doing wheelies which I'm not into I'd hate to see the damage that puts on my wallet
 

· "Sorry babe,payload is 120lbs"
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249 Posts
Sorta like mine really. Got an 02 and cylinder #1 isnt firing and sounds REALLY rough, I can even feel it in the ground when its running! Just dont know whats wrong. Dont think I threw a rod b/c the engine wouldn't be running. Do I need to pull the motor? Any ideas?
 

· i love lamp
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4,153 Posts
Discussion Starter · #19 ·
9K miles... that's unusual, were you riding the rev limiter?

who's doing the work? shop in vegas?
no i wasn't riding the limiter at all. i was doing a consistant 6k in 6th all the way from Ann and 95 down to the galleria mall. dropped at the light.

and Racer's edge is doing it for me up on spring mountain and valleyview



make sure and hone out and clean up head where bucket goes. looks like it got little scarred up. nothing that cant be fixed.

really no point in milling head and running thinner gasket.. unless ur trying to get to certain squish number. but clearances just wont allow much. stock headgasket is .020 thick. split it and its .010. YEC gasket thats not findable now is like $150 and it measures .012 i think. plus new stock gasket is cheap..but i always reuse old one anyways when i split it. it is worth little gain and worth doing. glad u caught it man. it could have turned ugly.


now let me know when u put pistons in. ill tell u thats mother!!!! not much room if u put rings and pistons into cylinders and then slide them onto motor, and jsut put in pins and circlips. its major pain to do. be careful with those damn circlips... dropped one in motor 3 times last time i put on cylinders. had to take off pistons, take off cylinder, and then put all pistons back in cylinder, then put cylinder on motor and try with circlips again. tried stuffing papertowel in to stop circlips..but there jsut not enuff room once u get 2 middle ones done and working on 2 outer pistons.

oh i know it would be a pain in the dick, that's why i'm just saying screw it and have someone do it for me.
 
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