Hi,
First off I'm new to this forum and would like to say Hi :]
Second I'm a newby at motorcycles and fixing engines and such.

Well the problem I'm experiencing just now with my GPZ 550, 82' is that it is making a very loud rattling noise from the left side of the engine. Described in greater detail below.

A week ago it was starting with no problem ready to go in a second. After experiencing some bad weather this week it has gotten progressively worse.
Upon start up, you could initially start it with the starter, now you have to jump start.

Once it starts it sounds like a bobber almost, with a loud noise coming from the left side of the engine (I couldn't exactly find where from, you could hear it if you moved from front to back all the way along even under the carbs), which I fear might be one of the pistons. Accompanying the sound you hear a puffing sound as if there is air escaping the combustion chamber. In addition to that when you touch the unexposed spark plug wire on the left side of the bike it shocks you a bit. Also the sound gets less loud but more frequent the more throttle you give it. It remains through all the gears and through the range of RPM. When you leave the throttle alone it dies quite quickly, and again you have to jump start.

Now I thought that would be the cam chain tension-er, but I'm not sure, some how I don't think it's that.

Initially I thought it was just battery problems due to the weather, as I've always had a very slight rattle and didn't pay attention to it as another person with the same bike had the same sound.

I really need your help folk, I would also make a video but I'm not sure I really want to do that, because it might just screw the engine over even more.

Any help would be appreciated
Thanks

That's a video of the week before the bike started acting up.
Mar 13, 2013 4:24 AM | Facebook

 

A good plug wire will not shock you. I would check there first.
Do you have a manual on how to check things out?

Welcome to KF

 

I have a service manual supplement for my bike, it's not proven to be very helpful so far. I've been trying to find the book but no luck.

I'll check the plugs once it stops snowing, as I don't have a garage and I don't know anyone that does I'll have to do the repairs outside. :/
Thanks for the suggestion. :]

 

Straight off, the ignition leads and the battery. If you're miss firing on one or more cylinders it will sound like a busted tractor. The crank in those drives the gearbox via a multi row primary chain that sounds terrible when the motor is badly out of balance as it's being slapped around. If you got a shock off the lead, replace them. Don't use any of that silicone rubbish, either. These are wire cored leads.
As for the battery, cold weather can be the final straw for an old battery. Check the connections and electrolyte level (top up with distilled water ONLY. Never I repeat NEVER use tap or rain water) and if possible give it a couple of hours on a charger. If that doesn't sort it, get a new battery.

 

I went to one of the motorcycle shops in Dundee and they said to check the spark plugs, ignition coil, and just generally the electronics. Told me to run it for a min and check which of the exhausts are cold and which are hot, if two of them as in 1&4 or 2&3 are cold it means it's a problem with the ignition. So I'll do that as soon as I have a chance to ( stops raining in bloody scotland ) but yea I feel pretty confident it's not the engine causing this :] after the talk. However he said " That bike is ancient, I'll give you advise but I'm not touching such an old bike. "
Anyways it's not the battery as I swapped it with my scooters battery and it starts straight away. It's got plenty of life in it.

That was a good shout out Dark Angel, the mechanic said pretty much the same thing. As it runs what it actually does is drag one or more cylinders and is causing that tractor like noise and hence it dies quickly after the throttle is released.

Thank you for the suggestion :]

 

I used to ride a Z550G1 (had two in fact). I still hold a soft spot for them. They have almost exactly the same engine as yours and use the same workshop manual. I wish I'd never sold my last one, especially when and how I did.

 

Found out what was wrong with it.

1st - If you have a similar problem, as most members suggested check the wiring and spark plugs.
My problem was that salt built up on the tops of the spark plugs and they weren't making a good connection. So just sand down the salt or scrub it off.

That got the engine running...

2nd - That really loud noise you could hear, was not only because the pistons were being dragged around but because the cylinder head gasket had blown. So air and oil was escaping.

Which I am yet to replace as I'm quite busy with exams right now.

Hope this helps someone else too :]
I might put on a video on how to replace the head gasket if I can be bothered.

 

You located that issue visually? The air escaping was mentioned in your original post but not the oil.

Congrats on the diagnosis. You may as well get your tools ready to check and/or adjust the valves while you tear things apart.

 

Well I noticed the oil after I went in for a closer look, when the engine was cold. Now I've tore down the upper body of the engine, up until the head gasket. It looks like it's blown and it's where you could hear the sound coming from.
One thing I noticed though was that the pistons looked very bad, as if they had a bit of rust on them and an accumulation of particles on top of them. The bores where the pistons go look nice and shiny but the pistons themselves are concerning. It might be because of rich fuel mixture or just bad quality fuel.
I've taken pictures but I haven't gotten around to ask the mechanic, I talk with, what he thinks of this. So I'm gonna go in tomorrow and see what he says of it.
I might need to change the pistons. I'll take a look at them and see if they are loose and all. I could just try and clean them up a bit if they aren't loose.

Anyways I'll upload the pics tomorrow so you guys can have a look as well :]

*Edit*

The photos below \/

http://imgbox.com/gallery/edit/FGjXg...yKai29Wxf0JXwO

 

Clean up the pistons and cyl with no 1 diesel and a bronze or nylon brush to take the carbon off of the piston tops. Straight edge the cyl deck and head. Feel for an edge at the top of the cylinder for wear. From the pictures, it does not look that bad.

like you mentioned, after you check the pistons and rods for clearance or excess wear/movement, you will know more.