Bike won't start

[quarterliter]

Not what I asked. I'm almost done trying to help you here.

[FvnnyL3tt3r1ng]

Originally Posted by quarterliter

Not what I asked. I'm almost done trying to help you here.

I didn't know you had started.

[quarterliter]

Go ahead swap in another engine. Be my guest just trying to help you. But you have yet to take mine or many others advice. Your reading of less than half the usable value leads me to believe you messed up your testing process. But you maintain that you are correct. At 14k the chances of the compression being that low is almost none.

[FvnnyL3tt3r1ng]

Originally Posted by quarterliter

Go ahead swap in another engine. Be my guest just trying to help you. But you have yet to take mine or many others advice. Your reading of less than half the usable value leads me to believe you messed up your testing process. But you maintain that you are correct. At 14k the chances of the compression being that low is almost none.

Not so. My last engine had spun bearings in the rods at ~19k miles and I have only driven harder since that. I'm just waiting til money comes in to get another bike. I push these engines to their max. Trust me.

You can't tell me a compression test is that difficult. WOT and crank it til the needle tops out. What's so hard about that?

[quarterliter]

You killed an engine in 19k? What do you do? Run crappy oil, beat it when its cold, or a combination of the two?

[cuong-nutz]

Justin, have you done a wet compression test? Put some oil into the spark plug hole and test compression again. It jumps up significantly you have worn rings like I did.

[FvnnyL3tt3r1ng]

Originally Posted by cuong-nutz

Justin, have you done a wet compression test? Put some oil into the spark plug hole and test compression again. It jumps up significantly you have worn rings like I did.

I can't do any testing right now the connector for the leak down tester is stuck in the cylinder. I plan on putting the spare in though and doing some head maintenance so I can visually see what is going on at that time.

[FvnnyL3tt3r1ng]

Originally Posted by quarterliter

You killed an engine in 19k? What do you do? Run crappy oil, beat it when its cold, or a combination of the two?

I've always ran Mobil1 full synthetic motorcycle oil so you tell me if it's crappy. I've never beat an engine cold but I guess I'm not an expert like you so maybe I've been doing something wrong.

I ride it on one wheel a majority of the time I imagine that has something to do with it.

[quarterliter]

You are a victim of oil starvation then. Didn't realize you were a "stunter." What made you choose a 250 as your stunt bike?

[FvnnyL3tt3r1ng]

Originally Posted by quarterliter

You are a victim of oil starvation then. Didn't realize you were a "stunter." What made you choose a 250 as your stunt bike?

Didn't know I was so into it when I bought the 250, been too poor to buy anything else. I'll have a 600 in a couple months though so I can be easy on the ninja.

[quarterliter]

90s 600s can be had cheap around where I live. Might not be a bad choice. Maybe a Honda F2 or F3

[cuong-nutz]

Originally Posted by FvnnyL3tt3r1ng

I can't do any testing right now the connector for the leak down tester is stuck in the cylinder. I plan on putting the spare in though and doing some head maintenance so I can visually see what is going on at that time.

I have that issue from time to time. What you need to do I'd find a long flat screwdriver and turn it out. Or get some thread lock on and let it harden and remove.

[FvnnyL3tt3r1ng]

Originally Posted by quarterliter

90s 600s can be had cheap around where I live. Might not be a bad choice. Maybe a Honda F2 or F3

^^^That's actually the route I'm going. I'm gonna be able to afford a used one in Dec.

[FvnnyL3tt3r1ng]

Originally Posted by cuong-nutz

I have that issue from time to time. What you need to do I'd find a long flat screwdriver and turn it out. Or get some thread lock on and let it harden and remove.

Worked like a charm why didn't I think of that?!?

[FvnnyL3tt3r1ng]

OK, time to rip the head off this engine and see what's going on. I don't have money for new gaskets so it'll just be on hold for a little while after I pull it.

[FvnnyL3tt3r1ng]

Pulled the head and block off the engine tonight and I see that cylinder one piston was scraping against the cylinder wall leaving marks on the sides of the piston. There was also rust on top of the cylinder. I'm going to be spending some time cleaning this engine up, lapping the valves, replacing the head gasket and putting new rings on and probably a new piston.

[FvnnyL3tt3r1ng]

2013-10-21 19.55.36.jpg

[FvnnyL3tt3r1ng]

Thoughts?

Both engines I have have had issues with clyinder one somewhere. Last engine had spun bearings in rod 1.

It makes sense since it's the last to get fed oil.

I wonder what these markings mean. My last engine didn't have any of these on the pistons....

[The_big_dill]

Parts weren't lining up is my thought, also possibly insufficient lubrication. Could a warped head do that?

[quarterliter]

Oil starvation/possibly getting some contaminants in the engine from bad air filtration. Something fairly good size. Have you stunted on this specific engine?

[FvnnyL3tt3r1ng]

Originally Posted by quarterliter

Oil starvation/possibly getting some contaminants in the engine from bad air filtration. Something fairly good size. Have you stunted on this specific engine?

Yea. I wonder why compression was low still

[n4mwd]

A few points.

First off, you can't trust the reading from a Harbor Freight compression tester. Its more important that they are approximately equal.

Second, if the oil filter isn't installed correctly, it will not filter the oil. Contaminants get into the passages and destroy the bearings. Engines can be trashed because the order of parts isn't right and the oil gets through unfiltered.

[FvnnyL3tt3r1ng]

Cleaned out the cylinders last night and aside from the rust it seems like they had some uneven wear? Especially cylinder one. Am I imagining things and is just some rust caked on or did they actually wear unevenly??

I'd rather not replace the rings if I could avoid it because of costs. It looks like I'll have to hone them a tad bit though.... The engine had about 14k miles on it is that normal.

[cuong-nutz]

Justin, you'll need to check for roundness of the bores before you do anything. Best bet is to take it to a machine shop so they can check it and to make sure your head and block is square.

You'll probably need a new set of rings if they damaged/scored.

[FvnnyL3tt3r1ng]

Originally Posted by cuong-nutz

Justin, you'll need to check for roundness of the bores before you do anything. Best bet is to take it to a machine shop so they can check it and to make sure your head and block is square.

You'll probably need a new set of rings if they damaged/scored.

I got a set of telescoping gauges coming in the mail today

Edit: Actually I just tracked it and it won't be here for a while. Wow harbor freight way to be the slowest online store.

[FvnnyL3tt3r1ng]

Cut out a gasket for the clutch cover but oil still leaks. Im just going to go buy some gasket maker type stuff from the auto store I'm a little frustrated after cutting out a gasket from paper. Last owner had some grey gasket maker on there and it worked fine but I'll find something less elastic. Can't ride tonight because of this stupid issue.

[n4mwd]

Originally Posted by FvnnyL3tt3r1ng

Cut out a gasket for the clutch cover but oil still leaks. Im just going to go buy some gasket maker type stuff from the auto store I'm a little frustrated after cutting out a gasket from paper. Last owner had some grey gasket maker on there and it worked fine but I'll find something less elastic. Can't ride tonight because of this stupid issue.

What type of gasket paper did you use? Did you get staples or somebody to print it for you?

[FvnnyL3tt3r1ng]

Originally Posted by n4mwd

What type of gasket paper did you use? Did you get staples or somebody to print it for you?

Not exactly sure on the name but I think it was called "gasket paper." It was tan in color.

I traced it and the outline was good but the holes were a pain to cut out. Of course by the pressure relief valve the oil comes out of the cover so I'm just gonna do it the easy way and order gaskets from now on.

[n4mwd]

Originally Posted by FvnnyL3tt3r1ng

Not exactly sure on the name but I think it was called "gasket paper." It was tan in color.

I traced it and the outline was good but the holes were a pain to cut out. Of course by the pressure relief valve the oil comes out of the cover so I'm just gonna do it the easy way and order gaskets from now on.

If you used gasket paper then it should have worked fine if everything lined up. The factory ones are just paper themselves. Were the mating surfaces clean?

To cut the holes, just use a hole puncher.

[itslocfoo]

so what happen? does it run yet?

[FvnnyL3tt3r1ng]

Originally Posted by itslocfoo

so what happen? does it run yet?

It runs just had a oil leak from the right cover

[itslocfoo]

Originally Posted by FvnnyL3tt3r1ng

It runs just had a oil leak from the right cover

how did you fix it?

[fast1075]

There is no mystery about what killed the piston in the picture, or the rust in the cylinder. Oil starvation pure and simple. Oil starvation seized the skirt, lack of oil and overheating destroyed the oil film on the cylinder, and it rusted soon after. I hope your "next" bike has a dry sump oiling system or you will kill it too. Or better yet get a 2 stroke bike and run premix in it.

My creds? I have earned a living as a mechanic and engine builder for 42 years.

[FvnnyL3tt3r1ng]

Originally Posted by fast1075

There is no mystery about what killed the piston in the picture, or the rust in the cylinder. Oil starvation pure and simple. Oil starvation seized the skirt, lack of oil and overheating destroyed the oil film on the cylinder, and it rusted soon after. I hope your "next" bike has a dry sump oiling system or you will kill it too. Or better yet get a 2 stroke bike and run premix in it.

My creds? I have earned a living as a mechanic and engine builder for 42 years.

Good to know. Can you explain to me what a dry sump system is and are they on a lot of sport bikes?

I'm not sure how the engine became oil starved as the volume was fine. I do believe it was in need of an oil change though. 6000 miles or 6 months as the owners manual states is a little far fetched.

[fast1075]

A dry sump engine does not store the oil in the crankcase. As the oil circulates thru the engine and makes its way into the crankcase area, a "scavenge" pump sucks up the oil and returns it into a remote oil tank. The pressure pump sucks the oil from the tank and feeds the engine.

A dry sump system is less affected by stunts such as wheelies.

A 250 Ninja engine is a "wet sump" engine. All the oil lives in the bottom of the engine. If you do a wheelie, the oil goes to the back of the engine. when that happens, the oil pickup (the "screen") loses contact with the oil, and sucks air.

You can't lube a motor with air. Either quit the wheelies, or get a different bike that has a dry sump. A Buell air cooled bike would be a good choice since they have dry sump oiling. But remember if you do a wheelie long enough, ALL motors will starve for oil and fail.

[FvnnyL3tt3r1ng]

Put new paper gasket on clutch cover. Filled oil. Bike starts up and runs like a champ.

Countdown to next rebuild.

[quarterliter]

Get a buell blast, they have a dry sump. Fast1057 is right here, its amazing that the ninja will run that long without oil pressure, but its only a matter of time till this happens again. Maybe more catastrophically next time.

[FvnnyL3tt3r1ng]

Originally Posted by quarterliter

Get a buell blast, they have a dry sump. Fast1057 is right here, its amazing that the ninja will run that long without oil pressure, but its only a matter of time till this happens again. Maybe more catastrophically next time.

Yeah lessoned learned here. Don't do wheelies on a 4 stroke 250cc with .01 Hp

[quarterliter]

Displacement and horsepower are not what caused this engine harm. Any wet sump engine would have experienced the same issue. But for real, a buel blast would be your best bet.

[n4mwd]

The Ninja 250 isn't going to oil starve during a wheelie because the oil pickup is at the rear of the engine. As long as its got the required 2 quarts in there, it should have no problem. The problem is the opposite - braking. Something like a stoppie is going to starve the engine for oil. Even heavy braking is bad.

Another thing that is VERY bad is after an accident and the bike is on its side, if the engine continues to run, its running without oil. Usually the carbs will flood and stall the engine, but not always.

The Ninja does have a problem with oil frothing at RPM's greater than 7K or so. What happens is that the oil gets splashed around so much that it becomes a bit frothy and then foams out of the oil breather. If its hooked to the airbox then it just gets sucked into the engine and burned. But if its just sitting there with a little pod, then it runs out on the street.

A dry sump system would probably fix that, but IMHO isn't not worth the extra weight on the Ninja. Just don't do stoppies or hard brake any more than absolutely necessary and keep an eye on the oil level.

Justin uses full synthetic oil which can tolerate a second or two of zero pressure without damage. I don't have an explanations for the pistons, but in this engine, the crank bearings are the first to go in a zero oil pressure situation. When the tolerance is measured in microns, it doesn't take much to mess it up.