[WFO-KZ]

"As for the top guide and tensioner, I wouldn't have thought that would make a difference which order they're installed?"

It depends on the design of the guide and the design of the tensioner.

If the guide presses down onto the chain it will put additional stress onto the chain if the tensioner is already pushing on the chain. This applies only if the design of the tensioner is such that it can only move in one direction. Kawi used this design on a lot of its bikes and I don't know if they used it on yours.

If on your bike the chain tensioner is free to move in and out while the bike is running, then you can ignore what I said about sequence.

 

[WFO-KZ]

For the benefit of everyone I edited your title to include the year of your bike.

 

[teejo]

"As for the top guide and tensioner, I wouldn't have thought that would make a difference which order they're installed?"

It depends on the design of the guide and the design of the tensioner.

If the guide presses down onto the chain it will put additional stress onto the chain if the tensioner is already pushing on the chain. This applies only if the design of the tensioner is such that it can only move in one direction. Kawi used this design on a lot of its bikes and I don't know if they used it on yours.

If on your bike the chain tensioner is free to move in and out while the bike is running, then you can ignore what I said about sequence.

Ah, no worries. The tensioner is a (somewhat) basic design, but looks to be able to move in and out freely. I'll take it off again in the next few days and install it in that sequence just in case though.

For the benefit of everyone I edited your title to include the year of your bike.

Thank you!

 

[WFO-KZ]

Just bear in mind not to rotate the engine with tensioner removed.

 

[Kawasakian]

.........because you could jump the valve timing!!!

 

[WFO-KZ]

Also, I do hope you have a service manual because on a lot of these tensioners they need to be "reset" after removal.
In other words you cannot just unbolt the tensioner and then reinstall it without following a reset procedure.

A service manual is the most important tool in your toolbox.

 

[teejo]

Also, I do hope you have a service manual because on a lot of these tensioners they need to be "reset" after removal.
In other words you cannot just unbolt the tensioner and then reinstall it without following a reset procedure.

A service manual is the most important tool in your toolbox.

I've got one that I downloaded, but it says to refer to the "base manual" for anything relating to the timing. I assume they're referring to the owners manual, which doesn't have anything in it regarding timing either. These are the only manuals I've found that I don't have to buy.

Service Manual:

Owners Manual:

 

[WFO-KZ]

The Base Manual is not a reference to the owner's manual. It is a reference to the main service manual.

 

[Kawasakian]

How's your German?

 

[teejo]

How's your German?

It's a shame the English version of the Workshop manual is such a rare find! Currently going through and translating the pages that I need. One camshaft is definitely out of timing. Have to figure out how to line these ones up with TDC as its a bit more complex with more than just one cylinder!

 

[WFO-KZ]

Can someone here confirm that the EL250 shares the same engine with the GPz250?
I think it does.

If this is true it may make it easier to find a manual for the GPz.

 

[teejo]

I believe I've found the issue.

Looks like both camshafts are out by a tooth. Couldn't take a clear photo of the other side, but the line falls below the jug. I'd say they'd jumped when the timing chain was loose.
An issue I'd forgotten to mention is that I cant fully rotate the crankshaft manually. I'd say one of the valves is attempting to open and colliding with the piston, which would explain the noise. I'll have another look at the German manual to make sure I line everything up correctly.

 

[Kawasakian]

Don't force it, you may have bent the valve already. Es könnte kaputt sein , Vielleicht besteht noch Hoffnung!

 

[WFO-KZ]

With normal cam chain wear, the chain will stretch so a slight misalignment may be ok but definitely needs to be looked at closely. The manual should give you the number of chain links between the marks on the sprockets. Count the links as this can help determine if it jumped one tooth on one cam.

But before we go there, can you answer one question? In your first post you say "the spark plugs hadn't been adjusted correctly". Was the gap too big or too small? This could be an important clue.

 

[teejo]

With normal cam chain wear, the chain will stretch so a slight misalignment may be ok but definitely needs to be looked at closely. The manual should give you the number of chain links between the marks on the sprockets. Count the links as this can help determine if it jumped one tooth on one cam.

But before we go there, can you answer one question? In your first post you say "the spark plugs hadn't been adjusted correctly". Was the gap too big or too small? This could be an important clue.

Hey sorry, been a bit busy lately! The spark plug gaps were too small. They hadn't been adjusted when they were bought so they were at the stock gap.

 

[WFO-KZ]

Ok, here is a theory that would explain the sudden knocking of the engine after a spark plug change and oil change.

The small gap on the old plugs may have been caused by the piston tapping on the spark plug. This happens when there is wear on either the wrist pin bearing or the crank bearings. By installing new spark plugs with the correct gap, the piston would once again start tapping on the spark plug. This explains the sudden knocking noise.

A simple test is to re-install the old plugs and see if the noise goes away.

 

[teejo]

@Kawasakian @WFO-KZ

Well, I've got good news. The valves aren't showing any signs of major wear or damage on the cylinder side.

The only signs that the valves have been hitting the piston is the below photo. If that's the culprit, it doesn't look like its been tapping for long.

I've been lining the timing up incorrectly.

These marks here:

are NOT TDC!!! I assume these are the firing marks looking at the position of the cylinder

The actual TDC marks are very hard to see. I thought I'd had a look all around the rotor, but must not have had the head torch on so missed cyl 1 TDC.
Cyl 2 TDC mark I DID see, but stupidly enough, it's hidden between what I assume is the part/serial number so I just thought that they were unimportant markings.

Looks more obvious now though, could've saved myself a bit of disassembly (as to remove the cylinder head, I had to prop the bike on a stand, remove the side stand, remove the radiator, unbolt a bit of frame to then slide the exhaust out to then remove the cylinder head)

As for the cylinders, I can still see honing marks on every surface, so it seems I've lucked out there. No free play in the pistons either!
I'll probably order a new head gasket. I'm this far in, so might as well replace that.

Screw it though; it was fun, even though we've had a stretch of 27-32°C days and the shed I was in was easily double that... 10 minutes and I was sweating...
Time to reassemble, I'll post an update once it's together again and with hopefully a much quieter engine.

 

[Kawasakian]

Clean all that carbon off the combustion chamber, and the tops of the pistons really well. That bike, judging by the looks of it's interior, went through long periods of either no oil changing, or just adding oil, and not changing the filter. Stay on top of that, and it may last a while yet.

 

[WFO-KZ]

While it is apart, I would do a valve leak test. With spark plugs installed and the cylinder head upside down and level on a workbench, fill each combustion chamber with varsol and see if any of it leaks past the valves.

 

[teejo]

While it is apart, I would do a valve leak test. With spark plugs installed and the cylinder head upside down and level on a workbench, fill each combustion chamber with varsol and see if any of it leaks past the valves.

Would mineral turps be a suitable alternative to varsol?