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Old April 28th, 2019, 01:33 PM   #1
gouvis
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Weird problem with rocker arms

Hi, I own almost 2.5 years a Kawasaki KLE 250 which uses an ex250ee ninja motor. My problem is that since I bought the bike I have a really weird problem. My rocker arms wear out really fast. I have tried everything. At the beginning, I changed some of them, which I have found that they were worn out. Then after some kilometers my valves start ticking. I adjusted them again and torqued them at 13 ft/lbs. After some kilometers the ticking came back and this time, after I felt that the bike lost power,I found out that one of the rocker arms broke in half. I replaced it, adjusted everything and the engine work again perfectly for 500 kilometers until the problem came back. At first I thought that the problem was the oil pressure because I found that my camshaft were a little worn out too. I replaced the head with one that was in really good condition with all the internals, the oil pump, all the o rings of the lubrication system and I installed an oil pressure gauge. The problem came back. As for the pressure, the manual says that this engine should have over 3.5kg/cm² at 4000rpm 90 Celsius engine temp. I believe that this is impossible for this small engine so I check the newgen's manual and says 1-1.5 bar at the same conditions. I believe that this is the right value, as both motors share the same lubrication parts. I have 1.4 at these conditions so it seems that lubrication isn't the problem. I tried also a local mechanic that builds drag motorcycles and has experience with this engine as he has customers with the same motorcycle to check if I was doing something wrong and the problem came back. I wasted money and time on this bike and I really want to make her run perfectly. Does anyone share the same problem with me, or has anyone managed to overcome it? Please help!!! I read everywhere that this engine is bullet proof and it drives me crazy.

PS. The dog-ears on the broken rocker arms are everytime in perfect shape, so it's not an overtorque problem

PS no2. I haven't managed to complete 3000km on this motorcycle.
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Old April 28th, 2019, 05:21 PM   #2
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You may have oil-flow problem. Hook up mechanical oil-pressure gauge to oil-line at head and verify oil-pressure is to spec. You can also do oil-pressure mod to increase pressure slightly.

What kind of oil have you been using? I suggest only high-quality full-synthetic oil like Motul 300V or Motorex.
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Old April 28th, 2019, 05:44 PM   #3
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Using non-synthetic oil is not going to break rocker arms or clog oil passages.
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Old April 28th, 2019, 08:32 PM   #4
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Hmm, depends upon usage. High ambient temps and racing usage doesn't bode well for dino oil.

What is oil-level? Is engine level in frame after swap? What about doing jumps and wheelies? I'm wondering if oil-pump sucking up air would cause this problem?
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Old April 29th, 2019, 12:24 AM   #5
gouvis
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My pressure gauge is installed next to the motorcycle's oil pressure switch using a T fitting. As about oil I use motul 5100 10w50. When I had the valve cover not installed, I checked to see if I oil passes through the small holes at the top of the camshaft jurnals using the starter to spin the engine. I saw oil coming from every hole and also my oil pressure light on the dash went off just by spinning the engine with the starter. Also just for your info, with the oil temperature being over 90 degrees Celsius I get 1.3 bar at 4000rpm, 3 bar at 10000rpm and 4 bar at 13000 rpm. Has anyone measured the oil pressure of his bike just to check my values?
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Old April 29th, 2019, 03:29 AM   #6
gouvis
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Also it is not a swap. Kawasaki KLE 250 comes from factory with an ex250ee engine. Everything is stock on the bike. I am not doing wheelies or jumps as I use this bike mostly for road use. Also I just disassemble the valve cover and found that this time one of my exhaust rocker arms popped and hit the valve's retainer which made the collets pop. As it seems this time the dog ear broke but I don't know if it broke first or broke when it popped and hit the retainer. I will remove the camshafts and see what's the damage. Now as it seems I may have a bad valve except the broken rocker arms and worn camshaft. Thanks I really don't know what to do anymore. I may just quit. A lot of money on parts and etc
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Old April 29th, 2019, 07:53 AM   #7
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Some Kawasaki twins have experienced issues with the valves dropping into the valve seats, which may explain the ever-increasing valve clearances.

To break a rocker I would expect that you would need to contact the piston with the valve.

This is what happened when the cam timing slips and a valve contacts the piston on our CRF150R -











I'd check the cam timing and also take a look at the top of the piston if you can.

I wouldn't run a 10W-50 oil. I'd run a synthetic 5W or 10W-40. There may have been some oil-related issues in the past if the cam was chewed-up, though you can see our cam got messed-up due to the other damage.
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Old April 29th, 2019, 08:31 AM   #8
gouvis
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After I disassembled the engine I found that the timing was correct and all the other 7 rocker arms where in great shape. But the one valve which rocker arms broke has stuck in the guide and will not move at all. So it's bent for sure

Last futzed with by gouvis; April 29th, 2019 at 10:50 AM.
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Old April 30th, 2019, 07:35 AM   #9
jkv45
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Quote:
Originally Posted by gouvis View Post
After I disassembled the engine I found that the timing was correct and all the other 7 rocker arms where in great shape. But the one valve which rocker arms broke has stuck in the guide and will not move at all. So it's bent for sure
If you decide to rebuild that engine I would first confirm what caused it to happen so your fresh engine won't experience the same fate.

I initially had no idea what caused the valve to hit the piston on our engine (bought it damaged), but after some research and close inspection found that the hub for the cam gear is pressed onto the cam and had rotated, allowing the valves to get out of time.

The Ninja's cam isn't attached in the same manner, but something caused the two to connect.
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Old April 30th, 2019, 09:07 AM   #10
gouvis
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Quote:
Originally Posted by jkv45 View Post
If you decide to rebuild that engine I would first confirm what caused it to happen so your fresh engine won't experience the same fate.

I initially had no idea what caused the valve to hit the piston on our engine (bought it damaged), but after some research and close inspection found that the hub for the cam gear is pressed onto the cam and had rotated, allowing the valves to get out of time.

The Ninja's cam isn't attached in the same manner, but something caused the two to connect.
I'm not sure if I'm going to rebuild this engine. I may swap it with a newgen one. I believe that this valvetrain design with the rockers being free to pop from their place, is really stupid for such a high rev engine. I believe that's the reason Kawasaki changed this design on the newgen. IIRC Nissan sr20det engine has a similar valvetrain design with rocker arms. Same problems there. If the engine over revs , rocker arms will pop
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