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Uhh ohh.

By youknowm3kcrf10,
in CRF250R & RX

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youknowm3kcrf10

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I think i jinxed myself. I was gonna wait another month to rebuild...But i was riding this morning, for about an hour, and i heard a wierd kind of scratchy squeeky noise ? :applause: I dont have a clue what it is or was. And then it cut off. Now it sounds horrible. So i have the seat and plastics off. Im going to tear it apart(first time on a 4 banger) and find out what ill need. Could it just be my valves? Thanks

Kris

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weatherman64

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Is it seized? My guess is it is a bearing... maybe cam bearing or crank bearing. And its not your valves. Check the cam bearings.... see if they spin freely. If they spin freely, then its time to split the cases to crank bearings. Do not try to split the cases without a service manual

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youknowm3kcrf10

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Is it seized? My guess is it is a bearing... maybe cam bearing or crank bearing. And its not your valves. Check the cam bearings.... see if they spin freely. If they spin freely, then its time to split the cases to crank bearings. Do not try to split the cases without a service manual

Ok thanks. I sure hope its not the crank bearings...That could be a job.

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youknowm3kcrf10

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I would get a service manual and tear down the whole engine and find out what went wrong, did you have adequate oil? Check every piece and go from there.

I ordered the manual the other day. Yeah i just changed the oil last weekend. I have the head cover or whatever its called off. now what do i check for?

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youknowm3kcrf10

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Is it seized? My guess is it is a bearing... maybe cam bearing or crank bearing. And its not your valves. Check the cam bearings.... see if they spin freely. If they spin freely, then its time to split the cases to crank bearings. Do not try to split the cases without a service manual

Nope its not seized. It still starts. Just sounds alittle screetchy, and it will cut off after a minute or two. and sometimes it makes alitle backfire type noise lol. :worthy::applause:?:naughty:?:eek:? I just bought it about a month ago...sux. bad.

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Honda_250f_rider

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I would stop where you are at and wait for a manual so you can follow the steps and properly take it apart and inspect everything.

Once you have the valve cover off, set it to top dead center compression stroke, use the kickstarter until you hear the clunk of the auto decompressor, and then you will have to move the cam gear in a clockwise direction if you are looking straight on at it, until the 2 marks line up w/ the top of the cyl head, then pull of the plug on the right side of the motor, and make sure those gears are lined up perfectally, there is a line on the gear under the cover, line that up w/ the mark on the cover.

Then you can check your valve clearances w/ some feeler gauges

Intakes .004 - .006

Exhaust .010 - .012

Then Begin taking apart your motor, when you take off the cam bearing caps make sure you do it in a cross pattern so you dont warp anything, same w/ the cylinder head, but first you have to take out your cam chain tensioner...

Once the head is off take the cylinder off also, stuff rags in everything so nothing will fall in, take off the old piston, measure it for fun and then you can set it aside... You will be replacing the piston, suggest a wiseco high compression one.

Also look at your cam, see if the bearings are seized, can they move freely?

Then Start inspecting the connecting rod, if nothing is bad then proceed to split the cases and insptect the crankshaft and oilpump and other important things down there.

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youknowm3kcrf10

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I would stop where you are at and wait for a manual so you can follow the steps and properly take it apart and inspect everything.

Once you have the valve cover off, set it to top dead center compression stroke, use the kickstarter until you hear the clunk of the auto decompressor, and then you will have to move the cam gear in a clockwise direction if you are looking straight on at it, until the 2 marks line up w/ the top of the cyl head, then pull of the plug on the right side of the motor, and make sure those gears are lined up perfectally, there is a line on the gear under the cover, line that up w/ the mark on the cover.

Then you can check your valve clearances w/ some feeler gauges

Intakes .004 - .006

Exhaust .010 - .012

Then Begin taking apart your motor, when you take off the cam bearing caps make sure you do it in a cross pattern so you dont warp anything, same w/ the cylinder head, but first you have to take out your cam chain tensioner...

Once the head is off take the cylinder off also, stuff rags in everything so nothing will fall in, take off the old piston, measure it for fun and then you can set it aside... You will be replacing the piston, suggest a wiseco high compression one.

Also look at your cam, see if the bearings are seized, can they move freely?

Then Start inspecting the connecting rod, if nothing is bad then proceed to split the cases and insptect the crankshaft and oilpump and other important things down there.

Ohh god to the part about proceeding to split the cases. I did it on my kx, and man the transmission was a pain in the arse. im pissed. This is the second bike i have owned in a row, and less than a month they needed a bottom end rebuild. I do sooo much maintenance and still ends up messing up. I seriously think i have the worst luck when it comes to dirtbikes..or life

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moto_x2005

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do u know anyone thats good with motorcycle engines? especially competition 4 strokes? if u do have them help you if ur unsure how to take this motor apart i would either consult someone who does or have someone help you so u dont skip a step... its a good learning experience but its easy to mess somethin up to good luck and wait for ur manual before u do anything

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youknowm3kcrf10

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do u know anyone thats good with motorcycle engines? especially competition 4 strokes? if u do have them help you if ur unsure how to take this motor apart i would either consult someone who does or have someone help you so u dont skip a step... its a good learning experience but its easy to mess somethin up to good luck and wait for ur manual before u do anything

Unfortunatly no..I wish i did. I just checked the valves, they are on spec. So..I have no clue what the problem is. Any other things i should check for? Could it be the piston?

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youknowm3kcrf10

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ok i got the cam off. The bearing farther from the cam gear doesnt spin half as long or much as the one closer to the cam gear. And it sounds like the noise i heard when i was riding. I just spun it again, it is Def! the bearing. Should i order just a new bearing? Or is there a reason it went bad? Does all balls racing make a better bearing? or oem ?? I appreciate you guys help.

Thank you very much.

Thumpertalk is great.

Kris

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