rod knock on my 4 stroke 250cc? (wall of text)

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pimp1

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Hello, i have a question,

i have a Chinese bike a orion 250cc a 4 stroke air cooled engine. The factory that made it is ATV | Dirt Bike | Pit Bike | Electric Bike Manufacturer And Wholesaler-- China APOLLO/ORION/HYENG/HYENA Sports. and they dont want to send me a explosive view of the engine because im not a company bla bla.

To the problem is my bike has not been started for 2 months untill 1 week ago when i got new tiers and took it for a drive and i was just gonna heat it up to make the oil come out smoother.

but i pushed the bike to hard, and i think it was to little and very old oil in it since i drive the bike to the buss stop everyday "to get to school live to far away from it to walk to the buss"

anyway the engine got very very hot and i suppose i burned the connection rod, crankshaft
the "ball bearings" on them since they got no oil and i was driving a bit to fast in the hot sun :( the bike just randomrly died and was not able to start for around 15 mins " i was still able to "kick" so the pistion were not stuck or anything.

So after 15 mins it started and i was able tio ride home and it made a really wierd knocking sound like this rod knock Rod knock - YouTube

The bike is still working but i dont dear to ride it atm since i need to repair it asap to be able to go to school and all that

i bought a stethoscope to hear the sound better and check if it was my valves that was knocking when they opened and closed but it wasn't since i was able to hear them with the stethoscope very good and they did not knock

can it be this that have happen to my bike? ROD KNOCK!!! What it looks like inside the engine. - YouTube

and since my bike only have 1 piston should it even be able to start and all that with that huge damage that is shown in the video on the char?

this is how my bike almost look "same engine but the apollo" website says that this is a copy of my bike they made for 2 years ago but it looks the same

http://www.motorsweden.se/image_archive/showimage.php?version=5&image=OTktMDAwMw==

im going to open the engine and check if i can find anything broken and would be helpful if you could tell my what you think it might be that sound so bad :(

/sorry for my bad English im still learning

/from pimp1 in sweden msn/mail ufo-ufo-@hotmail.com
 

The_GDFP

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Most of the air-cooled 2v clones are copies of Honda's, so the microfiche for them will work, as will service manuals. Do you have a pic of your bike? There are pretty much two versions, pushrod and overhead cam. Note cam cover differences and base of PR cylinder.

OHC:


Pushrod:
 

pimp1

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il get you a picture in a few hours


edit my cylinder looks like the first one OHC but the shape of the other stuff is not 100% but thats justa diffrent design i suppose and also the pics i see are they "china" or real honda?
 
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pimp1

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Hello, Thx alot for the help :) i found a complete manual/repair guide to the CRF230F 250mb pdf :D

so im going the open the engine soon(Friday) but first i need some more help i have checked 1 of the valves and it was on 0,05 mm and that's good as far as i know :) ,
but the other one that i have not checked yet, because im not able to reach it without removing the engine from the bike,

can it just be that 1 of the valves that are wrong adjusted and hitting the piston that's causing the noise?

anyway im going to remove the cylinder first so i can check the rod bearings (can i check that by just removing the cylinder?) and i dont have to split the cam chain right? (dont have those tools) and its a weird chain not a normal one :p

again sorry for my bad English i don't know how to write proper sentences with this kind of words in it :p

/pimp1 all help are welcome :D
 

sean01

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yeah remove the head and barrel to check the conrod bearings condition..

once all apart grab the conrod and try and move it up and down, if the bearing is shot then it should have a bit of play in it..

also if its knocking as bad as you say then chances are there will be marks on the piston where it has been kissing the head..
 
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pimp1

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Okay. Thanks for the info i will start working with the engine later s today/ Saturday and come back with pictures :)



also since my English is crappy when you say head i suppose you mean the part where the valves are?, and the barrel = cylinder where the piston is?

also anything important to keep in my head while im doing that?
 
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my67xr

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yeah,
dont mess up the timing when you put it back together, eg putting the timing chain back on, dont let the chain slip a tooth on the cog etc etc
make sure both the markers are in the right places (camshaft and crankshaft)
 

pimp1

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okay, will keep that in mind.
one more thing that's wrong with my bike it fire flames out of the exhaust pretty often and beginning of the exhaust there is a little hole (from one of the bolts to the plates that protect the riders leg from the exhaust










-----------------------_little hole in this hole it is fire 24/7....._ muffler
Engine...................|......................................................|
@@@@@@.............|......................................................v
@@@@@@.............v..................space--------------- _________
@@@@@@----------*------------------------------------- - ;;;<--- fire sometimes
@@@@@@------------------------------------------------_________-
@@@@@@

dots are fillers and some - to hope you understand anyway :S

i hope it is understandable my engine gets hotter than my friends by far is there any way i can solve this while im fixing the other problem to?
 
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pimp1

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I have now removed the top and took some pictures

also when the cylinder still was there and only the valves and the top was removed i rotated the magnetic wheel (dont know what its named in english) and the piston went up and down and pulled up oil in to the cylinder so my exhaust is oily like a 2stroke thats because the oil ring on the piston is **** right?

that happen the last time i started it when it was knocking and it died in like 5 second because the spark plug was so oily i thought someone dipped it in a oil bath

anyway judge by the picture if you can see anything wrong :) it would be very helpful
Pictures by pimpen1 - Photobucket

its 2 pages
 

The_GDFP

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Piston is shot, and it needs a re-bore. Easy as. If the rod is bad, and crank needs replaced/rebuilt, that may have let the piston hit the head, collapse the top ring land and cause the bore issue.

eBay has plenty of oversize pistons for the clone, and the XR/ATC 185/200. I picked up a 67mm for $25 or so, and it has a little dome for more performance.

If the rod moves up and down, it needs fixed.
 
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pimp1

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piston is shot? what does it mean and do i need a new piston? the piston looks really bad in my opinion but the bike was performing good but the knocking and when the oil leakage in to the xplosion chamber.

same question as above do i need to make the cylinder bigger to fit a new piston turn it in to a mechanic?

the bolt that holds the piston seems to be impossible to remove because it so tight that the piston fells like its rusted can it be that the piston got to hot?

and the rod did not move up and down i was spinning the crankshaft (on the magnetic wheel) so it moved around like the engine was running

is there any other way than re-bore"making the cylinder bigger" and getting a new piston to stop the oil thingy or is the piston in a really bad shape so it might break soon anyway?

and the knocking will be inspected tomorrow when i am opening the rest of the engine and what side should i start on? to open`?

and one of the rocker arms seems to be in a bad shape " when i lift them and let them fall back again 1 of them stops in the middle for 1 sec then continue down does that need to be replaced? "
 

my67xr

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piston will need to be replaced. they are cheap enough new
you need new piston rings to match the new oversize piston
the bore will need to be machined larger, to clean up the damage,
either a rebore (cheapest way) or replace the cylinder/barrel

hold the rod that the piston is connected to and see if you can move the piston up and down a little
it will possibly need a new piston pin /gudgeon pin and clips to hold it to the rod and a new bearing?
then hold the rod and see if that can move up and down on the crankshaft
if it moves and you can feel a knock, both the crankshaft and rod will also need replacing or rebuilding

the rockers arms will be ok if they can move freely up and down when moving them with your fingers, if there is a tight spot anywhere, then they will need to be checked out by a mechanic.
and maybe replaced or rebushed?

the black oily carbon buildup on the pistons' head is caused by the rings being worn out from too many km's / miles use
the oil is getting past the damaged bore/piston rings, and fouling the spark plug.
you would also lose compression from the damage too, so less performance

the motor would not have lasted much longer.
it could have done more damage and the cost to repair this damage plus more may have been to expensive.
it could have possibly been cheaper to buy another brand new motor
.

at least you can have it fixed cheap enough now, as not too much is wrong, if you left it longer then ???? $$$$
 
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The_GDFP

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A low-wear Honda take-off jug & slug from eBay could be used, too, if money's tight.
Did you remove the clips from the piston pin, to get it off?

 

sean01

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all i can say is if the conrod needs replacing then id simply go with a new engine.

so far you need a full top end rebuild, add a bottom end rebuild as well and you can bet the repair bill will be more than a new one...

to me it looks like the engine has run low on oil and then overheated the cylinder causing the damage..

if you have already removed the circlips from the piston and the pin is still stuck in there then it just backs up my comment on over heating...

next step is to thoroughly inspect the bigend bearing (bottom conrod) if it is stuffed then dont bother about removing the piston...
also, the conrod bearing only needs the slightest bit of play and its stuffed. sometimes the play can be that small that sometimes it will go without notice..
 

pimp1

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the pin inside the piston is kinda stuck and I removed the clips and the piston. the connection rod sems to be fine at the bottom of it i will come back laters gotta hurry to school now :/
 

clunky64

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and then you could repair all this and find that it was the oil pump that let you down and has not pumped the oil up to the gudgeon pin
 

pimp1

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Hey again i made some videos of the problems with the engine (3 vids)

this is the knocking sound note it only knocks when i move it upp and down in that spot not when the piston are at top end etc and it is not the rod its something else.

And it only knocks when i move it upp and down not when i spin it like if the engine was running so maybe it just was because the piston was stuck and had pulled down every time by the rod scratching the cylinder?
so with a now piston and cylinder the knocking might disappear?
The knocking sound - YouTube

this is the piston that have to be moved with force to even wiggle back and forth
Piston got to hot and the bolt is stuck.AVI - YouTube
 

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