won't turn over with spark plugs in

[BigWill6586]

I have a 82 Honda 750 nighthawk it was my brother's bike. He let a nephew ride it for a while when he got sick and he run the hell out of it till, one day it wouldn't start. If you pull it, it will turn over without the plugs in. You put the spark plugs in and it won't turn over. My brother is gone now and I want to bring it back to life so any help would be greatly appreciated

[TOOLS1]

I hope you are not trying to pull the bike behind another vehicle trying to start it. That is very dangerous,  and could cause a lot of damage to the engine. However there are a few questions. Will the starter crank the engine over with the plugs out? Better yet, do you have a charger battery in the bike? These bikes will not run without a charged battery. If it will only turn a little when the plugs are in and then stop, the battery could be weak, or it has the wrong spark plugs in it. The plugs could be too long and hitting the tops of the pistons. Have you removed the plugs and checked for damage to the ends of them?
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[BigWill6586]

The battery was hot. Starter was being rebuilt at the moment. Yes pulled it behind a pickup, I'm experienced at doing this and no it's not safe. Ran great till kid got hands on it. Same plugs with no damage to them. With plugs in in 3rd gear it still slides the rear tire with my 280lbs on it

[TOOLS1]

I am wondering if there is a problem in the transmission. Have you removed the engine side cover and turned it with a wrench?
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[BigWill6586]

Yes I turned it in neutral and in gear with a wrench without plugs and it turned fine. With plugs it turned hard in or out of gear

[Ray]

remove the  cam cover.  sounds like a broken camshaft . not opening the valves

[BigWill6586]

I got the valve cover off but don't have the side cover off to turn it over yet but ,I'll check

[BigWill6586]

Both cams turn and look to be in great condition. But the chain that comes up from the crank feels sloppy ,but turns them. Is jumping time a possibility? If so how do you set the timing with the chain still turning the cams

[TOOLS1]

If that engine is not turning over while being dragged behind another vehicle while in 3rd gear, there must be something stopping the engine from turning. I doubt timing would do that. It is odd that it only does it with the plugs in. With the plugs out can you rotate the engine all the way through a revolution (two complete turns of the crank)?
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[BigWill6586]

Yes it turns great. I'm wondering on how you check cam timing and adjust it.

[TOOLS1]

You can find that in the factory service manual which can be downloaded from the manuals thread at the top of the home page here. If the cam timing changed while the engine was running, it is most likely scrap metal inside now. However that is rare. You say the engine will not rotate when the sparkplugs are installed, so there must be a problem there.
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[BigWill6586]

When it first happened it acted like it was so flooded that it was hydrolocked but it wasn't. And it ran home then wouldn't start

[Re-run]

I still wonder if the valves are not opening right, or at all. Removing the plugs releases any compression the engine might have, and so turning it over would be simple.

I would also turn the engine with the plugs out and make sure the pistons are all moving properly. Just look through the plug hole or stick a bamboo skewer in the hole just to make sure things are moving. Just to eliminate possibilities.

[BigWill6586]

I put some oil I n The cylinders and pulled it with The plugs out and it blew out the oil . but I will give it to the stick test. And thank you guys for all the help. The old g Old girl means The world to me

[BigWill6586]

It looks like the timing chain is about 90° off .

[TOOLS1]

If the timing chain somehow got 90* off, I would wonder how it got to be 90* off.
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