[teejo]

Hello all!
New to this forum, so hope I'm doing everything correctly.
I recently bought a beater Kawasaki Eliminator 250, I checked it running once I got home and the motor sounded great. The only issue was that it struggled to run. I could run it to the end of the street and back, but if I rolled off the throttle, it would stall. I could only start it on full choke (even warm) and run it on half.
After taking out the plugs, running a compression test on both cylinders, and inspecting the plugs, the fault ended up being that the spark plugs hadn't been adjusted correctly. I replaced these with new plugs anyway, as well as oil (only had 15w/40 for cars, so I put that in, read that it would be fine as a temporary alternative but clutch may slip. I replaced this with motorcycle oil the next day after running only once). After changing the oil to motorcycle oil again however, my bike has developed a loud knocking sound almost instantly. I made sure to keep anything away from the spark plugs holes while they were out, so that nothing dropped into the cylinders; almost certain I succeeded in not turning my cylinders into a temporary pinball machine for a bolt or nut.

Here's videos of the bike running:
Video 1 -

Video 2 -

I've checked the exhaust bolts, checked bolts located on the top end too. All were tight.
Noise doesn't go away when I pull in the clutch so its not the clutch housing as I'm aware that this is a common issue with these bikes. Clutch engages just fine.
Bike doesn't idle amazingly, but doesn't stall now. I've adjusted the idle screw still to no avail.
I'll check to make sure the new spark plugs are an exact replacement tomorrow as I replaced them with another brand, though I assume if the piston was hitting the spark plug, that cylinder would stop working.

Is there anything I'm forgetting to check before I assume this is a buggered top end? Just want to rule everything out before pulling the engine apart.

 

[WFO-KZ]

It would be helpful to know more history on the bike; how many miles on it, was it stored for a long while, etc.

Sounds like your carbs need a good cleaning.
What numbers did you get when you checked engine compression?

The noise could just be valve clatter from a loose valve. Check your valve clearances.

 

[teejo]

It would be helpful to know more history on the bike; how many miles on it, was it stored for a long while, etc.

Sounds like your carbs need a good cleaning.
What numbers did you get when you checked engine compression?

The noise could just be valve clatter from a loose valve. Check your valve clearances.

Hey WFO, thank you for the speedy response! The bike has 28,000kms on it, the previous owner said he hadn't started it for about a month. Compression was 140 and 135psi in each cylinder, but I think there was a bit of a leak as the spark ports are a bugger to get to, so I couldn't properly tighten the thread.
I'll check the valves hopefully tonight and get back to you!

 

[WFO-KZ]

Happy to help. Diagnostics is usually a process of elimination. We start with simpler stuff that is easy and cheap and then work from there. If valves are properly set, leave the valve cover off for now as we may have to check valve timing while we are in there.

I forgot to ask the year of your bike.

 

[teejo]

Happy to help. Diagnostics is usually a process of elimination. We start with simpler stuff that is easy and cheap and then work from there. If valves are properly set, leave the valve cover off for now as we may have to check valve timing while we are in there.

I forgot to ask the year of your bike.

It's a 1998

 

[teejo]

Happy to help. Diagnostics is usually a process of elimination. We start with simpler stuff that is easy and cheap and then work from there. If valves are properly set, leave the valve cover off for now as we may have to check valve timing while we are in there.

I forgot to ask the year of your bike.

So from the looks of it, the clanking noise is a stretched timing chain. Have a bit of experience in changing these as I changed one on an XT250T a half year ago.

timing chain

youtube.com

Tried to get the tentioner off to make sure its working correctly, but unfortunately one bolt is in a bugger of a spot, so i'll need to buy a 1/4" pivot drive tomorrow.

 

[WFO-KZ]

Sounds like you found a likely source. I am not familiar with this model but the service manual supplement shows a bracket that looks like a camshaft chain guide to keep the chain from flapping around as shown in your video.

Did your bike have that guide and if so, does it show signs of excessive wear from the chain? I would expect the guide to have rubber bonded to it. Does yours still have the rubber?

Here is the diagram I found. See guide held in place by T3 bolts.

 

[teejo]

Sounds like you found a likely source. I am not familiar with this model but the service manual supplement shows a bracket that looks like a camshaft chain guide to keep the chain from flapping around as shown in your video.

Did your bike have that guide and if so, does it show signs of excessive wear from the chain? I would expect the guide to have rubber bonded to it. Does yours still have the rubber?

Here is the diagram I found. See guide held in place by T3 bolts.

View attachment 46033

It did have that bracket, yes. Though I didn't notice any signs of wear, I'll check it properly tomorrow.

 

[WFO-KZ]

For it to make that much noise, I would expect to see significant wear. But I have to say it sounds more like valve clatter, or something other than chain related. Did you check your valve clearances?

 

[WFO-KZ]

The other thing I have seen happen is excessive camshaft wear due to running incorrect oil and/or not changing the oil often enough.

Have a close look at the camshaft lobes while checking valve clearances.

 

[Kawasakian]

If you listen to the timing of the "clatter", it sounds like very loose valves.

 

[WFO-KZ]

If you listen to the timing of the "clatter", it sounds like very loose valves.

It does sound like valve clatter which is what I said in post #2, but the part that bothers me is that according to the OP, the noise started right after an oil change.

That's a mystery to me unless the previous owner was running a very heavy weight oil just to make the engine sound more quiet... Let's hope not.

 

[Kawasakian]

That wouldn't be the first time that was done.

 

[teejo]

It does sound like valve clatter which is what I said in post #2, but the part that bothers me is that according to the OP, the noise started right after an oil change.

That's a mystery to me unless the previous owner was running a very heavy weight oil just to make the engine sound more quiet... Let's hope not.

The oil I drained seemed light, but that's just my guess, its possible he did do that.
Trying to remove this cover so I can set the cams to TDC. Any clue on how to get this off? No bolts are on that part, and I've levered it a bit but it doesn't feel like its going to unclip. I've looked at megazip, but that cover doesn't seem to be present in any diagram.

 

[Kawasakian]

That's the clutch cover, and it won't come off unless you take the bolts off. That cover has nothing to do with cam timing though? The cover you want to take off is on the top of the engine!

 

[teejo]

That's the clutch cover, and it won't come off unless you take the bolts off. That cover has nothing to do with cam timing though? The cover you want to take off is on the top of the engine!

Sorry, crankshaft, not camshaft. I'm a dope! How do I access the bolt on the crankshaft to line up the cam shafts? Usually there's two plugs that cover these (one for the bolt, one for the dashes to line them up correctly); I assumed they would've been under that cover

 

[teejo]

That's the clutch cover, and it won't come off unless you take the bolts off. That cover has nothing to do with cam timing though? The cover you want to take off is on the top of the engine!

Scratch that, helps if I look at the correct side of the motor...

 

[teejo]

Ok, so looks like one valve has no gap. Photo shows what I've measured in inches (Left is exhaust side).

Looks like all of the exhaust valves are falling under, intake is supposed to be .003 to .005, exhaust is .004 to .006
Also I took out the tensioner, checked it and reinstalled and that's removed the slack from the chain 🤷‍♂️ I think one camshaft has jumped a tooth as they don't seem to line up properly, but I'll confirm that later.

 

[WFO-KZ]

So we assume you removed the correct engine cover so you can see the position of the crankshaft in order to check valve clearance?

At those clearances I would say we can rule out valve clatter.

I think the sequence is install top cam chain guide first, and then install the chain tensioner. Otherwise if the guide presses on the chain, the chain will be over tightened. Service manuals seldom cover this aspect.

 

[teejo]

So we assume you removed the correct engine cover so you can see the position of the crankshaft in order to check valve clearance?

At those clearances I would say we can rule out valve clatter.

I think the sequence is install top cam chain guide first, and then install the chain tensioner. Otherwise if the guide presses on the chain, the chain will be over tightened. Service manuals seldom cover this aspect.

Not so much a cover, but the two plugs on the side, one revealing the bolt to manually rotate the crankshaft and one to reveal the timing lines. As for the top guide and tensioner, I wouldn't have thought that would make a difference which order they're installed?