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Oil blowing out of crankcase hose

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Hi guys what would cause oil to come out of crankcase hose.  I did the engine in this bike a few weeks ago and the guy call me today and ask what could cause oil to come out of that hose.

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Not sure what bike this is but its IMO either 2 things IMO if your getting engine oil into the air box via the crank case vent hose

1) Hopefully its the easy thing and the bike was dropped over and left down for awhile and some of the engine the came up the crank case vent hose into the air box.

2) Otherwise, check the engine oil level if its over filled, you have a transmission oil to engine oil migration issue and its either the right side crack seal or left side balancer seal BUT do both when you replace. if its say a 2004 to 2009 bike, there are lots of posts on this issues in this forum.

 

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The bike is a crf 250 the guy said it's oil coming out of the hose that is coming from crankcase 

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15 hours ago, bedrock said:

The bike is a crf 250 the guy said it's oil coming out of the hose that is coming from crankcase 

Sorry I was having a few beers last night :)

I meant what YEAR is the bike.

Normally the crank case vent hose goes into the top of the air box, hence if for example tranny oil is migrating to the engine oil side, it would over flow up the vent hose into the air box and out the bottom of the air box drain/small hose.

Check the engine oil dip stick to see if there is more oil than there should be otherwise post some pics

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He is going to drop it down in a day or so. I will check the year of it .

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What u mean the rings are not sealing in the cylinder forgot to mention that when I put the new crank and piston and rings I put new seals in the engine at the same time, that was a few weeks ago but only happen now

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You may have put the right side crank seal and or the left side balancer seal in the wrong way? If either of them are in the wrong way you need to check all the others.

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Hi guys the guy drop off the bike today he never had no issue with oil after but he wanted his valves check I took it apart and one exhaust valve got no shim how am I going to know what ticknest of shim I need now

 

Edited by bedrock

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