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Spraying oil on yz250f

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Posted by: Brandon250f---------------------

So I have a leak. Right side of the motor. There is a hole pointing right at the radiator hose. Its supposed to be there but i am pretty sure its not supposed to be spraying oil out. Im a new guy to the dirtbike stuff and dont have a clue. Can't find it on the manual. Thanks ahead of time.


Posted by: 1BAD250---------------------

are you sure your not over filling the crankcase? check the crankcase vent tube it could be pluged..like any 4 stroke engine it needs to bleed off the small amount cylinder presure they all build up its called [ PCV ] positive crankcase ventlation.hopefully didnot hurt the rings by over reving or also caled hi speed glazing.. if you check out the stuff i told you at first & thats not it then do a compression test if its much lower than its suposed to be then i suggest you folow the manual on seting your timming marks & pulling the jug & replacing the rings & giving the cylinder a light hone..hope this helps..1bad250..


Posted by: Ol'89r---------------------

[QUOTE=Brandon250f]So I have a leak. Right side of the motor. There is a hole pointing right at the radiator hose. Its supposed to be there but i am pretty sure its not supposed to be spraying oil out. QUOTE]


If it is the hole below the water pump housing, replace your water pump seals.


Posted by: VintageDirt---------------------

On my old '01 250F there's a hole for checking oil pressure. It has a machine screw in it unless you take it out to see if there's pressure. Could that be what you're looking at?


Posted by: oldguy---------------------

what he is referring to is the hole where on pre 2003 YZ250Fs the decompress lever cable enterred the head. When they put the auto decomp cam in Yamaha left the head the same and put a cheap rubber plug in there and it is very common that they fall out (it has happened on both of my 250Fs and numerous friends). The plug is held in by a 8mm bolt that often strips itself out from the vibrasion and because it only catches 1 or 2 threads you may need to have it helicoiled in. The easiest cure is to order one from the Thumper talk shop (about $18) or look on evilbay they are often available there. In the picture is the new plug (blue anodized) and facing right at you is the locking bolt (be very carefull when you tighten this it is very easy to strip)
The problem is so common I always carry a couple extras in my trailer to save the day for guys that loose them at races.


Posted by: oldguy---------------------

Here is the plug on Thumpertalk http://shop.thumpertalk.com/Decompr...p/qmr-03dpb.htm
They raised the price since I bought a couple last summer and it comes with a lip seal so don't buy an extra one (one should outlast your bike)


Posted by: Brandon250f---------------------

Wow. Thanx so much. Yes it is the plug. lol. Or it has to be b/c there is nothing there. i am ordering it right now. thanx again


Posted by: dezryder---------------------

oldguy's bike is unbelievably clean. Do you think its ridden or just on a stand in the living room?


Posted by: oldguy---------------------

Quote:
Originally Posted by dezryder
oldguy's bike is unbelievably clean. Do you think its ridden or just on a stand in the living room?
Thank you I just get a bit anal about maintanance sometimes . That photo was actually shot just after getting the bike back from Rich and Eric Gorr from the rebuild caused by loosing that plug. My son raced that bike for 2 seasons and it in fact now just sits on a stand in the garage waiting to be taken apart for that auction site



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