Hi Everyone. I'm new on the forum and joined in the hopes of getting some solid advice on my project bike. 

I purchased a non-running 1996 GS500E for around $500. Upon inspecting it I found that when in gear, the wheel moved about a 1/4 of the way, then stopped dead in it's tracks.  I thought that it may be a transmission problem. My local mechanic had a spare tranny so I figured he'd swap it out with no problem. As I found, the engine dropped a valve,  and the valve fell into the cylinder  and it was the valve that was preventing the wheel from moving. 
I haven't opened the engine. A friend used a flexible scope to pear inside via the spark plug opening. I have never dealt with a dropped valve and wanted input as to how to proceed next. What type of damage should I watch out for? Cracked head? Damaged cylinder walls? Damaged pistons? Etc... And of course, how much will this cost? Is it better to buy brand new parts? Or is it better to buy a used engine and swap it out? Any constructive input would be greatly appreciated. 

Quote from: raristy1 on July 28, 2009, 05:31:56 PM
Upon inspecting it I found that when in gear, the wheel moved about a 1/4 of the way, then stopped dead in it's tracks.

With the spark plugs removed or not?
If its with the plugs on, then this is normal.

I can't help you with anything more, others will chime in.

Much depends on how much the thing ran after the valve dropped, but that will be evident on teardown.  My first bike dropped a valve at highway speed, and by the time I got it shut down both steel valve tips had chewed entirely through the piston.  I ended up replacing the engine as a whole because it was cheaper.  It's also worth finding out why the valve dropped in the first place (over rev valve float? bad collet installation? broken valve spring? etc...) so you can check for other associated damage/hamfisting.

In any case, expect to replace at least the valve in question, likely its companion valve as well.  Piston probably, too.  If large bits got into the crank area and seized things, well, thats a whole 'nother kettle of fish.

The only way to tell for sure is to get the engine out and look at the nasty bits.  Head first, then follow the shrapnel down as far as it could have possibly gotten to. 

I'm sure others will chime in as well.

I bought mine w/ what I thought was the same problem. Upon diassembly it turned out to be the actual valve seat had dropped and wedged itself between the valve and the head. The local machime shop machined the head and put a new seat in. $75.00. I did all the wreching myself. Appearantly this is commonplace in these engines because the machinist knew exactly what I was talking about & how to fix it. Hope this helps

Go ahead and do a teardown and see the damage then go from their.

Quote from: lamoun on July 28, 2009, 06:48:36 PM

Quote from: raristy1 on July 28, 2009, 05:31:56 PM
Upon inspecting it I found that when in gear, the wheel moved about a 1/4 of the way, then stopped dead in it's tracks.

With the spark plugs removed or not?
If its with the plugs on, then this is normal.

I can't help you with anything more, others will chime in.

Thats not all true if the clutch is in it would spin with clutch out than yeah wont spin.

Quote from: drgnslayr72 on July 28, 2009, 09:04:52 PM
I bought mine w/ what I thought was the same problem. Upon diassembly it turned out to be the actual valve seat had dropped and wedged itself between the valve and the head. The local machime shop machined the head and put a new seat in. $75.00. I did all the wreching myself. Appearantly this is commonplace in these engines because the machinist knew exactly what I was talking about & how to fix it. Hope this helps

Sorry I am calling BS on this one ... seats do not drop ... there has been 1-2 cases especially of late of some of the seats chunking ... but its very very uncommon.

OP : Broken valve - and swapping trannies ... you do know to swap the tranny the wole motor has to come out and the whole thing disassembled right ? ... OK they did that and didn't notice the broken valve. sorry I am calling more BS here.

Broken valve definetly will damage the piston, the head itself is definetly dead, and cyl walls prolly dead too specially if it happened when running. I'd swap the motor though of late those have got impossible to come by.
Cool.
Buddha.

Quote from: lamoun on July 28, 2009, 06:48:36 PM

Quote from: raristy1 on July 28, 2009, 05:31:56 PM
Upon inspecting it I found that when in gear, the wheel moved about a 1/4 of the way, then stopped dead in it's tracks.

With the spark plugs removed or not?
If its with the plugs on, then this is normal.

Yes the plugs were removed & I understand what you may be saying. When the piston is in the compression stage, both valves are closed and it is hard to turn the wheel once the tranny is engaged. What has been occurring is a mechanical stoppage. In other words you can feel that there is something mechanically stopping you from turning the wheel once the tranny is engaged.

Quote from: drgnslayr72 on July 28, 2009, 09:04:52 PM
I bought mine w/ what I thought was the same problem. Upon diassembly it turned out to be the actual valve seat had dropped and wedged itself between the valve and the head. The local machime shop machined the head and put a new seat in. $75.00. I did all the wreching myself. Appearantly this is commonplace in these engines because the machinist knew exactly what I was talking about & how to fix it. Hope this helps

I hope that once I open her up I'll find a similar problem. Thanks for the input. I'll keep everyone posted.

Pull the plug - do you see a bashed plug ? ... look in the hole - you see the bits of the valve ?
One of those 2 are to be expected with a valve broken, Also the clearance on that valve will be 0 on the cam.
Cool.
Buddha.

Quote from: The Buddha on July 29, 2009, 12:44:17 PM
Pull the plug - do you see a bashed plug ? ... look in the hole - you see the bits of the valve ?
One of those 2 are to be expected with a valve broken, Also the clearance on that valve will be 0 on the cam.
Cool.
Buddha.

Thanks. Will check that next time I get a chance.