Major Problem.... Bent valve/snapped valve + who knows

[ag0d3k]

So its not my bike, but my buddy has an 06 FZ6, 12k miles, 2bros, excellent condition, great bike. Have only been on a few rides this year so far, but already changed oil and filter, new plugs, and the usual post winter stuff.

The other day we were out riding, after about a half hour we were coming down a hill to a stop sign, he downshifted and pop, sounded like a dirt bike. Luckily it was real close to my house, rolled it there. Knew it wasnt running on all 4, figured out #4 wasnt firing, took spark plug out and the tip was smashed/flattened. Took tank and airbox off, cracked butterflies and could see one of the intake valves bent. Not good. Decided to drop the motor. After taking the headers off one of the exhaust valve stems had fallen into the pipe. The valve head is wedged in the head, which is toast. My suggestion to him was get online and start looking for a new motor. a valve being smashed around in there did not do good things... hes taking it to a shop to have them tear into it and see how bad the internal damage is, which im assuming is toast, burnt toast...

Has anyone ever heard of this happening before? According to my buddy, at the end of last year, he brought it to the dealer he bought it from because it had noisy valves, and all they did was tighten the cam chain tensioner lifter. When we took the valve cover off, the cam chain was tight AF. no movement whatsoever. Not sure if thats how its supposed to be. Either way, we will find out how bad the damage to the cylinder/piston/rod/bearings etc etc is later today.

Hes not happy to say the least, my other suggestion was to by a honda.....:rockon:

 

[FinalImpact]

Hi and Welcome! That's a killer for First post on your buddies half. Heavy on the killer ( ). The cylinders in these are nikasil plated and I'm not sure who I'd trust to replate. In short, I'm guessing parts and labor is way more than the cost of the bike to rebuild. Well unless, done yourself so minimal labor.

As for the cause - the top end is pretty tough. However too much valve lash (clearance between lobe and valve) and it can knock the keeper off and drop the valve. This would have nothing to do with chain tension, just valve to lobe clearance. So if it was making a good tapping sound for some time OR since its last valve adjustment, that may be the cause. Although a broken valve spring or head coming off the valve are other likely causes.

IMO its not worth taking to a shop if you can pull the engine yourself. Although you could get lucky and find the cylinder is OK but once a valve head dances in there the odds are slim.

Good luck and keep us posted.

 

[ag0d3k]

Yeah when he told me that the valves were loud my first thought was they were out of spec and that caused it to drop and get destroyed. But he said he brought it in, Im not sure if they checked clearances or what, but all he said they did was adjust the CCTL. Im almost positive a new motor is the only option for him, if he wants to keep the fz, but hes optimistic for some reason...

Anyone have a motor they're trying to sell....?

Im a honda guy but have had 1 yammy before, a 91 FZR, loved that thing until it launched a plug into outerspace, heli-coiled it, sold it and bought my first f4i.

Anyways, ill update as soon as we know anything and hopefully I can get some pics of the guts

 

[Motogiro]

:welcome:to our great forum!

Another thought is damage to piston, rod and bearing. That type of damage could translate other problems and the will require a lot of love on the labor side leaving economic feasibility behind.

 

[The_Paragon]

Hmm. My bets are on a Just simply a broken valve, and alot of bad luck.

Cam chain tension wouldnt cause a broken valve for any reason.. at least I dont think so.. Unless of course it came out of time, by skipping a tooth.. but then you'd have damage to valves on all cylinders.
And besides, to my knowledge the cam chain tensioners are automatic anyway, unless its been replaced by a manual CCT. Not sure what adjusting this mechanic did..

Pull that baby apart and see what you can find.

If the nic on cylinder is still ok you might be able to get a new piston and find a used head somewhere.
Though I'd question the straightness of the crank now if the motor was stopped abruptly from a trapped valve head between the piston and dome

 

[kenh]

It definitely sounds terminal. With the way insurance works regarding repairing vs. replacing, companies are more likely to total a bike out for what we would consider is repairable in many instances. So, I would look for a used one that may have been involved in an accident and may have some road rash, but otherwise is fully functioning. I just found this one on Ebay..


2006 Yamaha FZ 600 FZ6 FZS6V Engine Motor Trans | eBay

 

[ag0d3k]

Im sure the damage is beyond repairable, at least cost wise. He took it to the shop this morning (against my advice) but we should know what the deal is this evening. I have one pic of the exhaust port, and you can clearly see the scoring on the head from the valve bouncing around