RM-Z250 Oil starved cam journal? How bad?

JoniX

JoniX

MADMATEMATT:
you look like you have had oil flow issues. i would be looking at the pump or the intake strainer for a problem. had same issue on a yz450f and one cog in the rotary pump had collapsed so it wasnt getting full oil pressure resulting in similar to this. for parts try partzilla.com. just dont get on nne order over $1000 or you will pay gst and import duty at customs :)
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Good idea. How much needs to be disassembled to access the pump? Do I need to split the whole engine?

MADMATEMATT:
ye mate, at speed. usually take off the rocker cover or oil filter cover when you first start her up and test.
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Wouldn't removing the oil filter cover cause it to loose oil pressure?

snowflake:
04-05
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So 04-05 Suzuki RMZ 250 are the same as Kawasaki KX 250f, thank you!
 
M

MADMATEMATT

you need to look at a schematic mate. mine you remove clutch and the side cover and its behind that. no need for full engine breakdown.
the oil filter should still get oil with cover off as its fed by a rotary pump usually. doesn't rely on sump pressure or anything like that.
 
JoniX

JoniX

I'm still confused about the filter, wouldn't removing it's cover cause the oil to spill there and not go on to lubricate the system? Or are the filter *the end* of the oil lines?
 
M

MADMATEMATT

JoniX:
I'm still confused about the filter, wouldn't removing it's cover cause the oil to spill there and not go on to lubricate the system? Or are the filter *the end* of the oil lines?
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hey jonas, yes if you run the bike with the oil filter cover off you will spill oil. i usually leave off and run bike for a second to make sure it is pumping up(if i have done a rebuild). prior to starting the bike i usually bleed this oil linel from the filter housing end, so you need to access this anyway. once i can see the oil pump is working ok, ill stop the bike and put the cover on. if your worried about oil spilling just run the bike for a minute with the oil cover on and then stop the bike to remove it and ck.
 
O

ossagp

I have yet to have a motorcycle engine with an oil pump that operates within spec fail to deliver oil to the top end by spinning the rear wheel in a lower gear. you dont have much trouble getting an rpm in the high idle range that way. It is inconvenient to do, but if you have to know it is workable. head off with the cam chain out of the way it is easy on some models to see that oil is getting to the head. cams in and sparkplug(s) out make it tougher, but if you just have to know then you do what you need. Many of us just prelube (as i am sure you will) and if we are at all nervous leave the cover or cover caps/plugs (when equipped) off and start the engine up. If I don't see oil flying before I want my silcone glove hand off the pipe I am sure I would be shutting off and looking for the reason. So far I haven't had a problem with a fresh pump. knock on wood.

If I owned your bike Jon I would be changing the pump. Many bikes are hard to blow compressed air into from the oil filter outbound, but usually pretty easy to blow back from the oil ports. just use a rubber tipped blow gun. Anyway, you can tell if istis stopped up at least. Just like blowing out would, blowing back can send some crud where you don't want it so plan for how to get rid of it. test your oil passages with a cotton swab to see if they are clean from flakes of metal (one of the reasons to change a pump too).

Your engine is a plain bearing where the cam is concerned, rather than a ball or needle bearing from what I am seeing. what feeds the cam bearings on the end that failed? Oil is usually thought of as a lubricant being it's first function. Spend some time with the people who design engines and the ones who design the oils and you find that trait is actually down the list. Design manuals vary but most of them show cleaning, cooling, and then lubrication on a system with an oil pump as there priority functions. your cam shows that the lubrication system failed to provide cooling for certain (blue cams being the smoking gun). No matter what you think the most important job is it is easy to see that none of the jobs get done if an adequate supply of the oil isn't there in the first place.

I take it you struck out on a machine shop possibly being of some service?
 
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JoniX

JoniX

MADMATEMATT:
hey jonas, yes if you run the bike with the oil filter cover off you will spill oil. i usually leave off and run bike for a second to make sure it is pumping up(if i have done a rebuild). prior to starting the bike i usually bleed this oil linel from the filter housing end, so you need to access this anyway. once i can see the oil pump is working ok, ill stop the bike and put the cover on. if your worried about oil spilling just run the bike for a minute with the oil cover on and then stop the bike to remove it and ck.
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Thank you for the tip!

ossagp:
I have yet to have a motorcycle engine with an oil pump that operates within spec fail to deliver oil to the top end by spinning the rear wheel in a lower gear. you dont have much trouble getting an rpm in the high idle range that way. It is inconvenient to do, but if you have to know it is workable. head off with the cam chain out of the way it is easy on some models to see that oil is getting to the head. cams in and sparkplug(s) out make it tougher, but if you just have to know then you do what you need. Many of us just prelube (as i am sure you will) and if we are at all nervous leave the cover or cover caps/plugs (when equipped) off and start the engine up. If I don't see oil flying before I want my silcone glove hand off the pipe I am sure I would be shutting off and looking for the reason. So far I haven't had a problem with a fresh pump. knock on wood.

If I owned your bike Jon I would be changing the pump. Many bikes are hard to blow compressed air into from the oil filter outbound, but usually pretty easy to blow back from the oil ports. just use a rubber tipped blow gun. Anyway, you can tell if istis stopped up at least. Just like blowing out would, blowing back can send some crud where you don't want it so plan for how to get rid of it. test your oil passages with a cotton swab to see if they are clean from flakes of metal (one of the reasons to change a pump too).

Your engine is a plain bearing where the cam is concerned, rather than a ball or needle bearing from what I am seeing. what feeds the cam bearings on the end that failed? Oil is usually thought of as a lubricant being it's first function. Spend some time with the people who design engines and the ones who design the oils and you find that trait is actually down the list. Design manuals vary but most of them show cleaning, cooling, and then lubrication on a system with an oil pump as there priority functions. your cam shows that the lubrication system failed to provide cooling for certain (blue cams being the smoking gun). No matter what you think the most important job is it is easy to see that none of the jobs get done if an adequate supply of the oil isn't there in the first place.

I take it you struck out on a machine shop possibly being of some service?
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Excellent information, good to know! So basically as long as I pre-lube everything, I should be OK starting the bike and leaving it on for a short period of time, even if oil does not flow or lacking oil pressure.

I had a look and changing the oil pump seems to be do-able for me but will take me some time, and I suppose the oil pump won't be cheap either.
I'll try blowing compressed air from the head then. I've got no ideas how the oil channels run on the engine, but blowing it back will send it to the filter I assume?

There's a ball bearing on the cams at end with the gears, and basically nothing at all (from what I can tell) on the other end. Just the cam on the surface of the head, with a layer of oil between. Is that what a plain bearing is? I'm unsure on translating some technical terms between Swedish and English.

To be honest, I do not know what a machine shop would be called in Swedish, nor where to find one :( But what can be done to recover my parts? I can't see how any bearing can be fitted on the cam as one of the lobes are in the way.
 
Mihylo33

Mihylo33

JoniX:
Thank you for the tip!

Excellent information, good to know! So basically as long as I pre-lube everything, I should be OK starting the bike and leaving it on for a short period of time, even if oil does not flow or lacking oil pressure.

I had a look and changing the oil pump seems to be do-able for me but will take me some time, and I suppose the oil pump won't be cheap either.
I'll try blowing compressed air from the head then. I've got no ideas how the oil channels run on the engine, but blowing it back will send it to the filter I assume?

There's a ball bearing on the cams at end with the gears, and basically nothing at all (from what I can tell) on the other end. Just the cam on the surface of the head, with a layer of oil between. Is that what a plain bearing is? I'm unsure on translating some technical terms between Swedish and English.

To be honest, I do not know what a machine shop would be called in Swedish, nor where to find one :( But what can be done to recover my parts? I can't see how any bearing can be fitted on the cam as one of the lobes are in the way.
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Do you plan on keeping this bike for a while?
If the answer is yes then go for a total rebuild oil pump and new head.... New new new!
 
JoniX

JoniX

Coming to think of it.. When I was riding last summer I saw what I would assume was drips of oil on my rear wheel rim and rubber. Maybe could have been gas as well. I really did not pay attention to it as I assumed it was coming from one of the vent hoses and was normal, or drips of oil forming under the engine due to my leaking valve cover gasket (oil checked/filled every ride, no major loss),or possibly my brake caliper leaking.

Could this have anything to do with my head? I'm not sure if it's normal to gas/oil to come from the vent hoses.
 
JoniX

JoniX

Mihylo33:
Do you plan on keeping this bike for a while?
If the answer is yes then go for a total rebuild oil pump and new head.... New new new!
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Most likely, yes. As long as it holds together and nothing else breaks.
Yeah I'll maybe do it, but right now it's money I can't spend on this hobby. I just use it to ride in the woods with my friends, nothing extreme, not really pushing the bike at all. Just getting from point A to B and enjoying the ride.
 
M

MADMATEMATT

JoniX:
Thank you for the tip!

Excellent information, good to know! So basically as long as I pre-lube everything, I should be OK starting the bike and leaving it on for a short period of time, even if oil does not flow or lacking oil pressure.

I had a look and changing the oil pump seems to be do-able for me but will take me some time, and I suppose the oil pump won't be cheap either.
I'll try blowing compressed air from the head then. I've got no ideas how the oil channels run on the engine, but blowing it back will send it to the filter I assume?

There's a ball bearing on the cams at end with the gears, and basically nothing at all (from what I can tell) on the other end. Just the cam on the surface of the head, with a layer of oil between. Is that what a plain bearing is? I'm unsure on translating some technical terms between Swedish and English.

To be honest, I do not know what a machine shop would be called in Swedish, nor where to find one :( But what can be done to recover my parts? I can't see how any bearing can be fitted on the cam as one of the lobes are in the way.
Click to expand...
shop around for the pump. i just got one for a yz450f for $25 aus! also your bike probably has a nonreturn valve between the oil filter and the pump, so you wont be able to "blow back" in that direction. i usually use a syring and suck it up inot the oil filter or as some here stated try blowing from the pump housing end towards the filter to see if blocked.
 
O

ossagp

Maybe Kawasaki did put a one way valve beyond the oil filter. The other things I have worked on from single cyls engines to 16 cylinder ones put the back flow preventer as close to the pump as possible when one is deemed necessary.

Anyway it is easy to check. I haven't bought a kawasaki oil pump other than for some kz 900/1000's. But other makers sell them reasonably.
 
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