8 bent valves

Hi i'm new to the fourm. i just got a 76' kz900 that has sat around for 20 years. when it was put away there was a engine problem. well i found it. 8 bent valves. also the cam chain was very tight. i'm looking to put the head together as cheaply as possible. any sugestions. also what might cause the bent valves. and the tight cam chain. i could not get it to loosen untill i removed the tower. it looks like there is a cam bearing or something smashed through the crank sprocket.

Best advice is one of two ways to go about it...

Contact Larry Cavanaugh (Cavanaugh Racing heads)....
www.flowbenchtech.com/porting/CRH/pricing.htm

He has other options of addtional service. Valves, seals and guides are your addtional costs, not his... If nothing else, he can at least tell you if the head is toast, can be repaired etc... (Of course, you'll need to send him the head)

The man does phenominal work... Straight up guy! Did mine as well as others on the forum which he is a member of so PM him...

The other would be to obtain another head possibly availabl of one of the members here or e-bay... This approach though, you'd still need to get some work done on it... Or possibly find one already accomplished for addtional cost.

Just a thought...

OMR

Ya, OMR hit it right on the head. I got luck and found a 7000 mile head off of a 79 kz 1000 for my z1 900 project. I got it off ebay, and it turned out to be what the guy said, but on e-bay you do take a risk. The only reason i swapped heads, is a few of my studs were broken off, and until i save up enough money that was the cheapest option.

well i went deeper today. i removed cylinder and pistons. and the final cam chain roller. i found a steel plate smashed over the sprocket on the crank that runs the cams. as it turns out the plate goes under the cam tower roller. mine was missing the rubber and the plate, well i found the plate. my father inlaw must have done some work and lost the plate, well we found it 19 years later.

would this change the cam timing enough to bend the valves. still seems odd. i havent found anything else wrong yet.
will soon get parts around to put together and see if she will run.

Yes. i worked on a Suzuki GS1100 where someone dropped a cam end cover down the chain galley. When the crank did a revolution, it advanced the timing by one tooth.

Agree w/ loudvhx. tho believe by more than one tooth. rec. new chain and close inspection of all rollers & bits/pistons & valve guides. (sevearly bent valves can crack guides at bottoms) luck G

wes_scooter wrote:

Hi i'm new to the fourm. i just got a 76' kz900 that has sat around for 20 years. when it was put away there was a engine problem. well i found it. 8 bent valves. also the cam chain was very tight. i'm looking to put the head together as cheaply as possible. any sugestions. also what might cause the bent valves. and the tight cam chain. i could not get it to loosen untill i removed the tower. it looks like there is a cam bearing or something smashed through the crank sprocket.

I was surprised at how cheap the dismantlers were selling used heads with all parts intact (it was like $200 for my 750 twin). If you think that one has damage, you may want to chuck it.

BTW: bent valves happen when somebody gets the camssaft timing off and the valves hit the top of the pistons.

Since it has been sitting so long, I would at the least pull the pan and look inside, good chance it has water in there, since we dont know if it sat outside or not.
my 5 cents, pull the motor all the way down and fix the things that need it,, it will be cheaper in the long run and faster

Well I can't speak for the others so I'll throw my 2 cents in....

These old girls are ~ 30 years old. As you have mentioned, yours has been sitting for the last 20 years. As your finding out, the old girl has some issues from one more more previous owners.

With that said and done, on a non running old bike restoration, the best advice any of us can pass on is as follows...

Strip her down, open her up, remove the head, cylinder, rebuild the carbs and split the cases. While in there, inspect every gear, bearing, replace all gaskets, seals & O-rings, replace at least the timing chain (you have other timing components obviously required replacement)... basically the works.

Is it a pain in the ass... Well hell ya but that's what we do, that's the fun in all this, taking an old POS beaten to death KZ and restoring her to her magnificent beauty. Not only cosmetically but more importantly, her insides as well...

I look at it this way... I have ~ $-5k to $6K in her and that's including tools, paint, parts you name it... Same time, where the hell you going to find a brand new 1015cc spanker for that price.

Sure I could have went cheap on some things such as only rebuilding the 26mm carbs that were on her but naw, wouldn't do or re-using the camshafts which are fine working cam shafts but again, wanted some extra umfca out of her... Maybe just clean off the piston carbon and only replace the rings with a hone job.... Kept the old suspension etc... All in all, she deserved more than that!

And there's the fact I waited 30 years for this... She had to be special and she was worth it...

OMR

You might get lucky and have nothing else wrong but then again you may end up throwing money away if you don't tear it completely down and inspect everything.

Common sense thing to do here is tear it completely apart and start from the start with the motor.....