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I have just had to change the head on my engine and a piston head. Have put it all back together, had the pistons 1 and 4 tdc and put the head on with the cams at the right markings. Its all gone back in the bike and it wouldn't start. Drained my battery so i boosted it and it started to go 4 a few seconds then stalled as i thawt it might do. It didnt sound quite right tho when it did go. I went to start it again and it seems that the battery has gone flat with the booster on there. This doesn't sound like to anyone that the engine may have seized up does it? There is oil in the engine(didnt forget that)!

As long as the starter turns the motor mate its not seized. If you hear a clicking sound when you push the starter thats just a flat battery.

It did turn it over but just the once, really slowly mate, dont think it would of got hot enough tho to seize it do u think?

Hmmmmm, if the engine doesnt turn dont hold the starter button in too long or you will burn the wiring up.

Filled with oil right? Try a bump start?

battery shagged, all earth straps ok??

I think the battery leads are ok baz, come to think of it now rob, those little caps that sit under the shim weren't in the head when i first got it out the box, im pretty sure they weren't in the engine when i put it in either, toad, do they need to be in there?

Not entirely sure what you mean, but the shims sit in whats called a bucket, and the buckets need to be there because they hold the shim in place.

On my old head (dont laugh) the shims rested on these little caps that will come out if you tip the head up, I'm guessing that this would put the timing out quite a bit as they are about 3 or 4 ml thick. Perhaps thats why it doesnt sound right when it eventually did start.

Yeah thats probably exactly why, the timing of the cams is spot on probably. Just the valves are opening and closing at completely the wrong time.

Think the worst you can expect is scratched surfaces on the cam lobes.

There are NO buckets in a ZXR400 head.

The shim is a small case hardened metal disc smaller than a five pence coin and is about 2.8mm up to 3.2mm thick.

The shim sits directly on the top of the valve stem.

I'll take a picture for you later.

Now for the bad news.
Reading what you have posted I think you've built your head and left the shims out.
The only thing that could drop out of the head if you turn it upside down is the shims.

NOT GOOD
If I'm right you will need to refit the shims measure the valve clearances and reset the clearances.
I'm prepared to bet you don't know which shim is which in terms of which valve it was on.

arghh. I thawt the shims were the silver shiny things that the camshafts rolls over....doh!!

Ok i stand corrected. Look forward to the pic!

Ok guys pictures

First one is a picture of some shims the 5 pence is for size




Next one is where the shim goes the screwdriver shows you exactly



Now we can see the shim in place



And finally I've put the rocker arm in it's correct position

If you did put the head together without the shims it will mean that when you started the bike it will have rattled like a box of nails and run very very badly

Your valves will not have been opening correctly ie too late and for too short a duration

It is unlikely that you damaged anything inside the cylinder
However there may be damage to the rocker arms and the camshafts and to the recessed washer shaped thingy on the top of the valve springs.

Sorry to be the bearer of bad news.
You could be lucky and just need to fit the shims and reset the clearances.
If you lived nearby I could come and do it for you....sadly you don't

Excellent picture Cargo! Glad to be educated by someone who knows rather than making some of my own conclusions and end up talking shite.