Busted cam shaft...

Wow I've never heard of a camshaft snapping in half. I would push the manufacture to replace the engine warranty or not.

What's next an axle or triple tree? If they give you a hard time tell them you are going to submit the broken camshaft for metallurgical testing to determine the cause of failure. I would be willing to bet the cause is use of substandard materials rather than oil starvation. Ridiculous!!

had one snap on me in my blazer... boy did it make a racket.
 
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Here are a couple of pics of the valves. I have to get into my brother's shop to get shots of the cam shaft and the rest of the engine.
 
Bike:

Cam shaft...
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Great pic man. Thanks for sharing =) Best of luck gettin er up and running!

My brand new 2000 CBR 929 had problems since it was new. One issue was during hard leans, when you hit a bump, the engine would cut out for a split second. SCARY! Turned out to be the kickstand safety switch. Second problem was with the F.I./Computer. When pulling a wheelie just as you got it up, it would sputter and try and die and then the FI light would come on and it would go into "limp home mode". It was in the shop for 18 months out of the 20 months I had it, Honda Canada would not authorize a computer replacement. I got fed up and just picked it up and rode it easy and it worked OK. A few weeks later the shop called me "we just had a 2001 929 get written off, if you can be here in 20 mins we'll let you swap the computer." I did, and it worked flawlessly ever since.

Don't lose hope. The scrap engine, etc. Something will come through for you.

-Jamie M.
 
Hyo engines are not very reliable... abt 25K kms, for me, the CCT let go causing bent valves. i replaced the valves but when i was tightening the camshaft screw, i had to be a stupid head and re-re torqued one of the screw which ended up breaking inside. breaking of the screw was completely my fault. not blaming Hyo for that. but for the CCT, Hyo is to blame. had to happen 2 months after the warranty expired too.. :(

anyway.. heres a pic of the old valves comparo with new ones.
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edit: OP, check hyosungsource for parts. i definitely recomend them for any stock Hyo parts.
 
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I just had the rear cams go on my 2008 Hyosung gv250. I was riding home and pulled into a parking lot to buy something and as I was shutting off the bike I heard a nasty grinding noise. Clattered like crazy when I restarted it so I had it towed. I didn't go to a Hyosung dealer because its too far away and out of warranty. A local mechanic thought the cam tensioner had gone so I bought that part and he installed it, but the bike had hardly any power so I told him to check it again. It turned out both rear cam shafts broke and the valves are bent too. I bough two new camshaft assemblies and four valves and a gasket from hyosungsource for $355 including shipping. I'm waiting for delivery now. I don't know the full cost of repair yet, but its certainly not worth scrapping the bike over. My worry is what caused this and will it happen again?
 
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Here are a couple of pics of the valves. I have to get into my brother's shop to get shots of the cam shaft and the rest of the engine.

The marks on your valves makes it seem like your valves have contacted the valve pockets on the piston. Ouch!
 
How loose are these CCT's getting? Are they getting loose enough that the timing gets way off and the valves hit the pistons breaking the camshaft?
 
I just had the rear cams go on my 2008 Hyosung gv250. I was riding home and pulled into a parking lot to buy something and as I was shutting off the bike I heard a nasty grinding noise. Clattered like crazy when I restarted it so I had it towed. I didn't go to a Hyosung dealer because its too far away and out of warranty. A local mechanic thought the cam tensioner had gone so I bought that part and he installed it, but the bike had hardly any power so I told him to check it again. It turned out both rear cam shafts broke and the valves are bent too. I bough two new camshaft assemblies and four valves and a gasket from hyosungsource for $355 including shipping. I'm waiting for delivery now. I don't know the full cost of repair yet, but its certainly not worth scrapping the bike over. My worry is what caused this and will it happen again?

Inherent design flaws and/or cheap manufacturing. Given that there are multiple engines with the same failure ... it is something built into the design, and if you replace the broken parts, it is a possibility that it could happen again.

How loose are these CCT's getting? Are they getting loose enough that the timing gets way off and the valves hit the pistons breaking the camshaft?

It's possible that this is the failure mode. Normally, if this were the cause, the failure would be preceded by an increase in mechanical noise from the engine - a slight rattling noise, generally most pronounced at lower revs, from the timing chain slapping around.

The pictures of the broken camshaft suggest a brittle failure. Camshafts are very commonly made from chill-cast iron but it's supposed to be heat treated to remove some of the brittleness and add some toughness. My money is not on tensioner problems but rather on improper heat treatment of the camshaft. And it's unlikely to be a manufacturing error ... it's more likely that the wrong material or heat treatment process has been used on every single one - built into the design.
 
It's a 2008 Hyosung. Just be glad it lasted that long.
Be thankful you didn't die when this happened.
They are throw away bikes.
Throw that one away and go buy another one.
 
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