1993 Ninja 250 w/ hard rod knock - KawiForums - Kawasaki Motorcycle Forums
 
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post #1 of 9 (permalink) Old 05-13-2018, 09:01 PM Thread Starter
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1993 Ninja 250 w/ hard rod knock

Got a 1993 Ninja from a friend. Said 'something' seems to be wrong with it. Sat for 4 yrs. Changed the oil, drained/filled the gas, jumped the battery and after a few tries it started up but, it sounds like it has bad bad rod knock. It'll idle for a few minutes but you can not get it to rev up past 1k rpm and and you can feel the pound. Watched a few YT vids on rod knock and it sounds the same, but, could I be wrong? Anything else sound like bad rod knock? If I fix it I'll do the labor myself and just have a shop machine the bottom end. Opinions on if it's worth it? The bike appears to otherwise be in fine shape for the age. Probably dropped once but does not appear to have ever been laid down.
thx
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post #2 of 9 (permalink) Old 05-13-2018, 10:14 PM
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"knocks" can also be severe piston slap or wrist pin slop. Not really any way to know until you start tearing into the motor. How did the oil look ? Usually a bottom end bearing issue will result in lots of silver metal in the oil.

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post #3 of 9 (permalink) Old 05-13-2018, 11:02 PM Thread Starter
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Oil appeared to be new. Guessing the last person didn't ride it much. Didn't notice any silver when I drained it or in the filter when I changed that.
 
post #4 of 9 (permalink) Old 05-14-2018, 12:38 AM
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Quote:
Originally Posted by [email protected] View Post
Oil appeared to be new. Guessing the last person didn't ride it much. Didn't notice any silver when I drained it or in the filter when I changed that.
I wonder if the previous owner changed the oil hoping the problem would go away. Wouldn't be the first time i've seen that.

I would pull the pan and check the rod bearings first since it should be the easiest thing to get to (relatively speaking).

If you don't have a copy of the service manual here is the 86 model since I couldn't find a later one at the moment. Keep in mind the 86-87 bikes were different in some key areas but it should be the same in regards to how to pull the oil pan and check to see if the bearings are shot.

http://service.tanga-moteurs.ro/data...0E1-2%20SM.pdf


Best of luck.

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post #5 of 9 (permalink) Old 05-14-2018, 09:13 PM Thread Starter
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Thx! I'll check it out at some point and post back.
post #6 of 9 (permalink) Old 07-24-2018, 11:13 PM Thread Starter
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I have the engine torn down. So far I obviously have more slop in one connecting rod than the other. Not lateral thrust or push-pull, but like the second hand on a clock where i can tilt the wrist pin end from side to side by a couple millimeters. The other one is much more snug, so that appear to be at least one problem. Just getting into measuring the parts now and I'm not sure how to identify the crank. The manual shows different expected measurements depending on the marking on my crank, which can be either 'none' or 'o'. I can clearly see a '1', a '10', and and 3 beige paint dots. Thoughts?

http://www.curtechit.com/lxforums/crank/crankpin.jpg
http://www.curtechit.com/lxforums/crank/IMG_1877.JPG
http://www.curtechit.com/lxforums/crank/IMG_1878.JPG
http://www.curtechit.com/lxforums/crank/IMG_1879.JPG
http://www.curtechit.com/lxforums/crank/IMG_1880.JPG
http://www.curtechit.com/lxforums/crank/IMG_1881.JPG






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Last edited by [email protected]; 07-24-2018 at 11:23 PM. Reason: Can't seem to get pics to appear.
post #7 of 9 (permalink) Old 07-26-2018, 10:12 PM Thread Starter
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Measured the bearings for the rods and they're thin. Thinner than the thinnest spec for any of the 3 sizes Kawasaki uses for this engine, so, no matter what crank or journals I have, it seems they need replaced. It's interesting to see the wear pattern. It appears they wore more on the edges than in the middle (on the cap side, which isn't shown here, but those readings were on avg 1 thou thinner on the edges). This would explain why the rod moved from side-to-side like the second hand of a clock (not lateral thrust). Also, the thickest area was at the bottom where it looks the least scuffed (most shiny; relatively small area), so it would seem that there is less wear when the piston is all the way up and all the way down, which I guess seems reasonable since the crank pin isn't pushing on the rod (ever so briefly) in either of those positions.
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Last edited by [email protected]; 07-26-2018 at 11:00 PM.
post #8 of 9 (permalink) Old 07-26-2018, 10:58 PM Thread Starter
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Where should I buy the parts, like rod and crank bearings?

Last edited by [email protected]; 07-26-2018 at 11:11 PM.
post #9 of 9 (permalink) Old 07-29-2018, 10:53 PM Thread Starter
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Anyone recognize the marking? If the manual I have is correct, there's an I, G, or H on the side where the rod and cap meet, and it may be inside a circle. Is this an 'I' in a circle? I figured it would be a stamp. this looks more like dye. Thoughts?
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Last edited by [email protected]; 07-29-2018 at 10:58 PM.
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