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1Back to top Go down   Oil leak from exhaust manifold Empty Oil leak from exhaust manifold Tue Jul 05, 2022 9:49 am

alin2em15

alin2em15
New member
New member
Hi All,

Ive been running my k100 for a couple months now and everything was going great for a little while.
I have now noticed more smoke on cold startups and sometime smoke after only sitting for about a hour.
i Have also now noticed an oil leak on my floor when the bike is parked for more than a few hours.
Quick visual inspection shows that i have oil dripping out of the exhaust manifold only on cylinder 4.
All other 3 cylinders are completely dry.

Thinking of first pulling the spark plug and looking down in the cylinder.
But wondering if it could just be a leaking valve stem seal?

Any help is much appreciated.

    

2Back to top Go down   Oil leak from exhaust manifold Empty Re: Oil leak from exhaust manifold Tue Jul 05, 2022 10:01 am

Point-Seven-five

Point-Seven-five
Life time member
Life time member
If you park on the side stand the bike will smoke on startup because of oil leaking by the rings.  It's a part of the "charm" of these bikes. 

I'm not sure why you only see it leaking on cylinder #4, it's possible that the exhaust header is not as tight on that cylinder as on the other three.  You might want to check the manifold nuts for tightness.


__________________________________________________
Present:
1994 K75RT
1991 K100RS


Past:
1988 K100RS SE
1994 BMW K75S
1992 BMW K100RS
1982 Honda FT500
1979 Honda XR185
1977 Honda XL125
1974 Honda XL125
1972 OSSA Pioneer 250
1968 Kawasaki 175
    

3Back to top Go down   Oil leak from exhaust manifold Empty Oil leak from exhaust manifold Tue Jul 05, 2022 10:10 am

alin2em15

alin2em15
New member
New member
The bike is always parked on side stand as i do not have the center stand anymore(part of it was snapped of when i bought the bike so it was removed.

While i do understand smoke is expected from our bikes.
What is considered excessive smoke.
I idle my bike for about 30 sec before i take off and still have smoke coming out about a half mile into my trip.
After that no more smoke.

If oil is leaking into the cylinders would it also be leaking past the exhaust valve into the exhaust port as well?

    

4Back to top Go down   Oil leak from exhaust manifold Empty Oil leak Tue Jul 05, 2022 2:36 pm

daveyson

daveyson
Life time member
Life time member
Remove the vacuum hose from the cylinder four throttle body. If there are any signs of fuel or dampness, the fuel pressure regulator rubber diaphragm is leaking, and excessive fuel is entering the cylinder. If that's the case, you need to replace the regulator. You might want to check if cylinder four has lower compression.

"~would it also leak past the exhaust valve? " Sometimes when the engine stops, cylinder four exhaust valve might not be closed, but yes, the header seal can't be too good.


__________________________________________________
11/1985 bmw k100rt (late model)  Vin. 0090567
 ~120,000 km
    

5Back to top Go down   Oil leak from exhaust manifold Empty Re: Oil leak from exhaust manifold Wed Jul 06, 2022 4:50 am

92KK 84WW Olaf

avatar
Life time member
Life time member
alin2em15 wrote:The bike is always parked on side stand as i do not have the center stand anymore(part of it was snapped of when i bought the bike so it was removed.

While i do understand smoke is expected from our bikes.
What is considered excessive smoke.
I idle my bike for about 30 sec before i take off and still have smoke coming out about a half mile into my trip.
After that no more smoke.

If oil is leaking into the cylinders would it also be leaking past the exhaust valve into the exhaust port as well?

No, its coming from the crank case side of the pistons, inside the bore as on side stand it slopes in the direction of the cylinder head. It gets past the piston rings end gap and into the combustioin chamber because on the side stand that's a slope in that direction.

The end gap opens as engine cools and the piston rings are not pinned. Your engine is most likely to be fine and that could also be the very likely cause of your oil leak at no 4.

You are going to get a big oil haze and half a mile of smoke if only using the side stand all the time. Kill the engine and lean to the right for about a minute before dropping on to the side stand is a good help.

Get yourself a complete 16v stand assembly or a K1100 stand assembly and it bolts straigh on as a complete unit.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 49,840 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

6Back to top Go down   Oil leak from exhaust manifold Empty Re: Oil leak from exhaust manifold Wed Jul 06, 2022 10:00 am

Laitch

Laitch
Life time member
Life time member
alin2em15 wrote:I idle my bike for about 30 sec before i take off and still have smoke coming out about a half mile into my trip.
You should ride off immediately after the engine is started instead of idling. Idling just wastes fuel and takes longer to burn off the excess oil. Set the starting speed lever to its first stop if the engine is sluggish and shut it off around 10 seconds after underway. That works for me down to ≈25ºF.


__________________________________________________
1995 K75 81,000 miles
Oil leak from exhaust manifold Usa-lo10
    

7Back to top Go down   Oil leak from exhaust manifold Empty Re: Oil leak from exhaust manifold Wed Jul 06, 2022 12:44 pm

92KK 84WW Olaf

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Life time member
Life time member
I never idle an engine, fire it up and ride. Idling causes excess wear too, gets up to temperature faster if you ride off gently.


__________________________________________________
1992 K100LT 0193214 Bertha Blue 101,000 miles
1984 K100RT 0022575 Brutus Baja Red 578 bought 36,000 now 89,150 miles
1997 K1100LT 0188024 Wotan Mystic Red 689 58,645 now 106,950 miles Deceased.
1983 K100RS 0011171 Fricka 606 Alaska Blue 29,495 miles Damn K Pox Its a Bat outta Hell Now 49,840 miles. 
1996 K1100LT 0233004 Lohengrin Mystic Red 38,000 miles currently 42,640 miles.

Past:
1968 Yamaha 80 YG1
1971 Yamaha 125 YAS-1
1968 Honda 125 SS
1970 Honda CD 175
1973 Honda CB500-4
Honda CX 500
    

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