Z250 Single

Oops - I just realised we were turning the crankshaft the wrong way around (clockwise instead of anticlockwise). The pistons didn't actually seem like they were doing anything when we were turning it clockwise.

Anyways, is just wondering what the effects of doing this are? I'm reading that I may have affected the crank and rod bearings, causing them to be unsealed or that I have affected the tension? We kept turning this a lot...

If so, what should I do?

Thanks.

PS - Patton, it was thanks to the Kz200 manual you put up that I saw the CAUTION regarding turning the crankshaft the wrong way. Otherwise I would have never thought it was a real issue. Thanks.

Ok so - disregarding the first question last night asking whether TDC should be at the very top of the valve movement or not, which came about from me and my friend reaching TDC via the wrong direction, hence it wasn't at the time (half a rotation) specified by the manual.

On top of the question regarding possible damage, I have noticed that the crankshaft turns a lot easier as the inlet valve is moving up, as I am nearing TDC. It literally almost "slips". Is this normal, or should it be a controlled motion?

My feeler gauges aren't very accurate I realised, but I am getting readings of between 0.5 and 0.75mm, which is no where near the 0.13mm maximum of the inlet valve, and 0.22 of the oulet.

sham wrote: ...have noticed that the crankshaft turns a lot easier as the inlet valve is moving up, as I am nearing TDC. It literally almost "slips". Is this normal, or should it be a controlled motion?

My feeler gauges aren't very accurate I realised, but I am getting readings of between 0.5 and 0.75mm, which is no where near the 0.13mm maximum of the inlet valve, and 0.22 of the oulet.

Would expect it's normal when hand-rotating the crankshaft for it to turn with varying resistance during different arcs while moving through the 720° (two full rotations of 360° each) covering all four piston strokes.

Resistance should be encountered during the compression stroke.
And varying valve spring pressures against the cams could also affect the perceived resistance.

As feeler gauges (aka thickness gauges) are inexpensive and readily available, would assure that the valve clearances are set within factory specs on a cold engine. This is critical both to engine performance and longevity/duration of valves and seats.

Good Fortune!

Hey Patton,

Yeh I have a set of feeler gauges but mine don't cover the full spectrum. I've been told that an imperial one might be better.

Anyways, I think I actually understand what's wrong with bike. It was suggested to me that I should probably do some reading on how 4 stroke engines actually work, and this is what I'm getting...

I can now connect the earlier issue I discovered (which I'm still facing), of fuel not being sucked through the carb, with issues with my engine - that fuel is not being pulled through because the intake cycle is not happening properly. This can be traced to the lack of compression (30PSI), as the engine will require 3 things to start.

1. Fuel
2. Compression of fuel by the piston
3. Ignition of fuel (spark plug)

My valve clearance being much larger than the specified maximums means that I am leaking air from the valves, which affects compression.

So for now, I think I will hold off on the gasket and o ring set, get my hands on a more accurate set of feeler gauges and hopefully borrow a torque wrench until mine gets delivered. I'll get some new oil and a new oil filter and change them and hopefully it will start up. Otherwise I will have to look for other reasons why I'm getting such low compression.

When performing the compression test, be sure to hold the carb in wide open position (as in maximum throttle).

Would also add a spoonful of motor oil through the spark plug hole into the compression chamber, and repeat the compression test. Then compare the test results.

Too tight valve clearance may result in the valve failing to fully close after the engine warms up to normal operating temperature, and risk burning the valve and the valve seat.

Too much valve clearance typically results in excessive noise while the engine's running, called "tapping."

Good Fortune!

Sham wrote:
"My valve clearance being much larger than the specified maximums means that I am leaking air from the valves, which affects compression."

Like Patton said, to much clearance will cause a noise. It won't cause a leak at the Valve.
Do the dry then wet compression test, after setting the valves to the proper cold engine clearances, and checking the cam to crankshaft timing. If it is 30psi dry, but comes up to 100+ when oil is added, then it may run but not as well as it should/ could. It probably needs a Top End rebuild.

Hmmm I'm under the impression that too much clearance will also affect the amount the valves can open? Which in turn might restrict compression as there is less intake?

The compression tests I've done so far are cold tests - do you mind explaining what a dry test is?

But based on what you're saying, and the information I'm getting, which is that too much clearance causes noise because it is causing a lot of wear and damage, I thought perhaps it might be better for me to take the engine apart anyways and have a look at it.

I tried removing the camshaft sprocket, and hence camshaft the the rest, but I encountered a problem. To do so, the manual says that I need to remove the lockbolt and washer pictured here:



However, this is what I see:



And strangely enough, here is another photo of the same area later in the manual:



What is going on here? Is it like that aluminum bit in the carb which I am suppose to drill out? I've had no luck seeing how this part of the engine comes together - for some reason its not covered in the microfiche for crankshaft, crankcase or engine covers, and there's no other categories I can see for it either.

Thanks

Please don't take this the wrong way, but you state "to be honest I have 0 experience in any of this and have 0 skills which could be of much use as of yet, but I'm hoping to at least get this bike running again..." Later, among other statements that show a lack of understanding of the basic principles of the operation of your engine you state: "My valve clearance being much larger than the specified maximums means that I am leaking air from the valves, which affects compression." which is the opposite of what the actual effect would be. Now you state: "I thought perhaps it might be better for me to take the engine apart anyways and have a look at it." What are you looking for?

I believe that you need to gain a much better understanding of how the internal combustion engine works before taking it apart if you expect to get it running again. I fear that by taking it apart you may end up with a box of parts that will never be put back together. It might be worthwhile to find a mechanic that can work with you and let you see how he/she first diagnoses what problem your engine has and then lets you see how to fix it. (You may find the problem is not internal to the engine and does not require a teardown.) If you simply pull the engine apart you may miss the opportunity to discover what's wrong with it. For example, I have seen some folks on this site rip engines apart with no clue about what they're doing and then when asked what the leak down test showed they said "what's a leak down test and how do I do it?" Sorry, too late, it must be down before ripping an engine apart. Do yourself a favor and get some hands-on expert technical guidance. That will greatly improve your understanding of your engine and improve your chances for successfully getting the bike on the road; after all, that is the goal. Ed

sham wrote: Hmmm I'm under the impression that too much clearance will also affect the amount the valves can open? Which in turn might restrict compression as there is less intake?

If the intake valve's clearance gap is so huge that the valve remains closed and doesn't open, there will be no intake sucked into the combustion chamber, in which event there's nothing to compress. And that's the same reason for holding the throttle wide open while conducting the compression test.

The compression tests I've done so far are cold tests - do you mind explaining what a dry test is?

The dry test is without oil added into the combustion chamber through the sparkplug hole.
The wet test is with oil added into the combustion chamber through the sparkplug hole

But based on what you're saying, and the information I'm getting, which is that too much clearance causes noise because it is causing a lot of wear and damage, I thought perhaps it might be better for me to take the engine apart anyways and have a look at it.

Tapping valves don't necessarily indicate any appreciable wear or damage. These are solid lifters (the kind that tap or click in normal operation). Correct clearance adjustment minimizes excessive tapping/clicking at normal engine operating temperatures. Absence of any audible valve tap when a cold engine is first started may indicate lack of sufficient valve clearance. "When they're clicking, they ain't sticking."

Once knew a guy that took his engine apart in the dark, and lost all the parts.

I tried removing the camshaft sprocket, and hence camshaft the the rest, but I encountered a problem. To do so, the manual says that I need to remove the lockbolt and washer ... However, this is what I see:

... What is going on here? Is it like that aluminum bit in the carb which I am suppose to drill out?

Nope. (But who's been nearby sharpening a pencil?)
The aluminum bit is a non-tamper plug pressed in position over the pilot adjustment screw.
If tampered with, teams of Federal marshals immediately descend from black helicopters.
They will likely place the plug in a most undesirable position.

I've had no luck seeing how this part of the engine comes together - for some reason its not covered in the microfiche for crankshaft, crankcase or engine covers, and there's no other categories I can see for it either.

More likely to be found in a "top end" category.
...

Good Fortune!

Hey thanks guys,

Ed - not taken the wrong way. I totally understand where you're coming from. Its frustrating because to learn I feel like I need to tear things apart to see it, but then I don't have the knowledge to know what I'm looking at. But I do plan to do the maintenance section of the manual once I get it running. I received some good advice to adjust the valves and the cam chain tension and see if it runs - if it does, to listen and to hear if its making a lot of noise, if so, then go with a tear down. I'll probably be posting a video of how it sounds when I get to that stage, if I get to that, as I won't know what it should sound like

Patton - thanks for clarifying all that. Yeh I realise I got it wrong with how the valve clearance affected the intake, but when I picture it then yeh definitely it's not opening up

In terms of the lock nut removal. The image from the manual was an "after" photo - the lock bolt and washer labeled has already been removed.

Thanks all.

Hmm...so I've removed the camshaft sprocket and removed the cam chain tensioner. Is the point of manually adjusting the tension just so that it can take up slack automatically again? That's what re-installing it is suppose to do.

Anyways, so I took the opportunity to measure free length of the chain tensioner spring. It's currently exceeded the service limit by 2mm, measuring 70.2 rather than 68.2mm. How important is this? Is it worth replacing immediately? Part number is 92081-1105.

My tensioner is also missing a flat washer. From the below diagram, it appears that its thickness is important in controlling the movement of the push rod. Is it possible for me to replace this just by measuring the groove pictured, or should I be ordering the specific part, 92022-077. These are being used on Kawasakis built today - would anyone have a bike which uses it and be able to measure it?



Thanks.

I believe the washer thickness is not as important as you are thinking, as long as it is not overly thick. The lock bolt sets the tensioner with the spring compressed for install. Then after the body is bolted up, you loosen the lock bolt, the spring then pushes outward and takes up the free-play in the chain. You can see the lock bolt has a Pin on the end, and the Plunger of the tensioner has a step in its grove. Once the plunger has moved outward it is in a deeper grove, no longer held stationary by the lock bolt. But the lock bolt must be in place and tight, so the Pin section can guide the plunger. Make sense?