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Help me DT250 oil trouble
- shogun
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Help me DT250 oil trouble was created by shogun
I own a YAMAHA DT250B (1975).
I want you to think about the problem from the symptoms.
・ When I started the engine for the first time in a month, oil spewed out from the oil breather hose and the ground was stained with oil.
・The engine started, but there was a lot of white smoke.
・Idle was low immediately after starting the engine, and the plug was wet with oil.
・ Oil consumption is very fast.
From the above, I thought that there was a problem with the oil pump.
Would changing the seals or gaskets fix it? And if there is another problem, where is it?
I want you to think about the problem from the symptoms.
・ When I started the engine for the first time in a month, oil spewed out from the oil breather hose and the ground was stained with oil.
・The engine started, but there was a lot of white smoke.
・Idle was low immediately after starting the engine, and the plug was wet with oil.
・ Oil consumption is very fast.
From the above, I thought that there was a problem with the oil pump.
Would changing the seals or gaskets fix it? And if there is another problem, where is it?
17 Jul 2023 06:22
#1
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- MarkT
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Replied by MarkT on topic Help me DT250 oil trouble
Which oil breather hose did the oil spew out from? The vent hose on the oil tank or the vent hose on the transmission?
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
17 Jul 2023 06:54
#2
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- DEET
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Replied by DEET on topic Help me DT250 oil trouble
Excessive Oil Consumption and smoke…..Oil pump check valve leaking allowing TWO STROKE oil to gravity drain from tank, flow through pump and fill up the crankshaft area.
Oil coming from breather tube…. If it’s the transmission tube, it could be a leaking right side crank seal.
If it is the oil tank breather, then it could be from over filling.
Oil coming from breather tube…. If it’s the transmission tube, it could be a leaking right side crank seal.
If it is the oil tank breather, then it could be from over filling.
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Where the Yamaha Enduro is still a current model...
Where the Yamaha Enduro is still a current model...
The following user(s) Liked this Post: asco, Ht1kid, LongStride, msavitt
17 Jul 2023 10:16
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- Lizeec
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Replied by Lizeec on topic Help me DT250 oil trouble
My .02¢ is a blown rh crankshaft seal allowing compression into transmission thus pressurizing cavity and forcing oil out breather tube, excessive smoke is also a symptom of blown rh crank seal.
17 Jul 2023 15:17
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- shogun
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Replied by shogun on topic Help me DT250 oil trouble
Thanks for everyone's reply.
The breather hose is a black tube attached to the crankcase.
The breather hose is not attached to the oil tank.
Does that mean there is a problem with the crank seals?
The breather hose is a black tube attached to the crankcase.
The breather hose is not attached to the oil tank.
Does that mean there is a problem with the crank seals?
25 Jul 2023 10:42
#5
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- shogun
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Replied by shogun on topic Help me DT250 oil trouble
2st oil blew out from this hose
25 Jul 2023 22:53
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- Superdad60
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Replied by Superdad60 on topic Help me DT250 oil trouble
Did you ever find your solution to this 2 stroke oil out the tranny breather hose?
I'm about to do the oil pump seal per recommendation but wanted to ask you
Thanks
I'm about to do the oil pump seal per recommendation but wanted to ask you
Thanks
16 Feb 2024 08:50
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- MarkT
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Replied by MarkT on topic Help me DT250 oil trouble
SuperDad... I don't recall you mentioning massive amounts of smoke and/or oil spitting out the exhaust on start up in your other thread?
An easy test for the oil pump check valve is to simply disconnect the oil line to the carb while it's parked for several days... directing the hose into a container is best. The check valve might drip a little but if you're losing a full oil tank in two weeks it would leak a couple ounces of oil in just 24 hours.
If it is the check valve, then you need to have a way for the autolube oil to get from crankcase to transmission which would also cause excessive smoke, likely oil fouled plug, and not-so-great running...
An easy test for the oil pump check valve is to simply disconnect the oil line to the carb while it's parked for several days... directing the hose into a container is best. The check valve might drip a little but if you're losing a full oil tank in two weeks it would leak a couple ounces of oil in just 24 hours.
If it is the check valve, then you need to have a way for the autolube oil to get from crankcase to transmission which would also cause excessive smoke, likely oil fouled plug, and not-so-great running...
1963 YG1-T, 1965 MG1-T, Allstate 250, 1970 CT1b, 1971 R5, 1973 AT3MX, 1974 TS400L, 1975 RD350, 1976 DT175C, 1976 Husqvarna 250CR, 1981 DT175G, 1988 DT50, 1990 "Super" DT50, 1991 RT180, 2017 XT250
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16 Feb 2024 22:15
#8
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- LongStride
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Replied by LongStride on topic Help me DT250 oil trouble
I purchased 2 different Yamaha Enduros that the right side crankseal was pushed out of the case, the bottom end had first filled with 2T oil, when first kicked over it pushed the crank seal out causing the symptom you described
2ET703 Central Texas
The following user(s) Liked this Post: MarkT
17 Feb 2024 06:42
#9
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- Superdad60
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Replied by Superdad60 on topic Help me DT250 oil trouble
Nailed it
my oil pump seal was damaged and the tank oil slowly drained into the crankcase as mentioned
thank you again forum
my oil pump seal was damaged and the tank oil slowly drained into the crankcase as mentioned
thank you again forum
The following user(s) Liked this Post: MarkT, Sneezles61
03 Mar 2024 05:06
#10
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