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dbshea

426, low coolant, "milky" oil. HELP

5 posts in this topic

Ok, so bought this bike a couple months ago for 1500, it's an 01 yz426. It was a white brothers "factory" bike, however other than a ton of aftermarket parts I haven't seen any paper proof. Anyway, rode the bike last presidents day and it was a beast. Found out it was up for sale and snatched it. I may be inserting foot into mouth. Went to go start it, and kick as I may the thing won't run. I know it's been sitting since last presidents day, so maintenance was definately in order. I Pulled the carbs to clean them out, drained the oil etc. Low and behold the oil looks like death, not really milky (i blew my impeller seal on a ktm and that oil was milky) but definately water was involved and it was old old old oil. The coolant was minimal, but not oily. What are the chances I blew my head gasket? This is my first 4 stroke, what all should i check? I know if i do replace the head gasket it is suggested to change out timing chain. What else could this be? Could it sitting so long have collected water? I'm crrossing my fingers that it's nothing and I'm freaking out, but what should i check? Any input would be great.

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Ok, so bought this bike a couple months ago for 1500, it's an 01 yz426. It was a white brothers "factory" bike, however other than a ton of aftermarket parts I haven't seen any paper proof. Anyway, rode the bike last presidents day and it was a beast. Found out it was up for sale and snatched it. I may be inserting foot into mouth. Went to go start it, and kick as I may the thing won't run. I know it's been sitting since last presidents day, so maintenance was definately in order. I Pulled the carbs to clean them out, drained the oil etc. Low and behold the oil looks like death, not really milky (i blew my impeller seal on a ktm and that oil was milky) but definately water was involved and it was old old old oil. The coolant was minimal, but not oily. What are the chances I blew my head gasket? This is my first 4 stroke, what all should i check? I know if i do replace the head gasket it is suggested to change out timing chain. What else could this be? Could it sitting so long have collected water? I'm crrossing my fingers that it's nothing and I'm freaking out, but what should i check? Any input would be great.

Im almost positive that its a head gasket. This is the biggest thing for having coolant in the oil, or somebody could have dumped the bike in high water and has water in oil. But since coolant level is low, I say head gasket. When your in there change timing chain and flush motor out with mineral spirits to get all coolant out. When it gets back together, ride it for 30 min and change the oil, then ride as normal.

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On my old 2 stroke YZ I had the same problem and it was just a water pump seal. Picked one up at a pool parts store for $3.00.

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I just got a 01 426 this winter in a trade. The oil looked fine at first. but after a couple rides it was obvious that there was water in it. So I did the water pump seals. This did not fix the problem!! Also my base gasket was leaking a bit around the coolant passage on the front of the motor. So I tore the top end down. I replaced piston, rings, deglazed the cylinder, new cam chain, new oil filter (stainless of course), New valves, cut new seats. I runs great now!!! And the best part is no leaks or cross-contamination. I agree with NOOB it is not the water pump. I hope you get it figured out. Good Luck.

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The water pump on a YZ or YZF cannot cross-contaminate the engine/trans oil unless the escape port below the pump has been blocked off. There is a separate oil and coolant seal, and an air gap between the two which is vented down and out so that coolant leaking from the pump escapes before it bears against the oil seal.

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