Crank seals leakdown testing?

giantvt104

giantvt104

New Member
Jan 6, 2012
261
7
0
deer park, ny
So ive been noticing lately a burned plastic smell after running a little and when i pull the plug it really smells strong. since i got it imo it seems like an excessive amount of white smoke coming out the exhaust. So taking this all into account i read up on it and was leaning towards leaking crank seals. I first warmed it up and drained the oil and it measured 730ml of 10w30. I replaced it with a little thicker oil @ 15w40 and put in exactly 650ml. I built a leakdown tester with a mighty vac that i have and some fittings from depot. pulled the carb and made a gasket for the exhaust. Pumped it up to 7psi and let it sit for about 20 minutes. It didnt move at all!! So i repeated and did the same thing but i took the oil fill cap off thinking that it could be holding leaking pressure. Still though same thing. 7psi not a drop leaked?? My quetsion is there any special ways or tricks to testing crank seals with leak down? am i doing it right? If so what else could cause white smoke and burned plastic smell?
Thanks guys..
 
if your leak test is holding, the seals are fine. However, did you put the piston at BDC so that the pressure can get to test the head gasket?

As for the burning, the reason I asked about the crank was that Slickerthanyou had a stuffer blow up and I believe it smelt a bit before it went.

what oil are you running and do you premix?
 
I thought i got it to bdc but i might not have been fully down. Its tuff to fit stuff down the cylinder to feel piston height with the fuel tank on. prob need to take the tank off to make sure its at bdc. The 2 stroke oil i use is just regular Echo Powerblend and i still have the oil inject do the mixing.
 
Yeah its on positive. Its really a craftsman proffesional basically a mighty vac but a much better made version. It has a switch for positive pressure or vacuum. Ill post some pics of what i put together.
 
Heres some pics of my tester
 

Attachments

  • CIMG1530.jpg
    CIMG1530.jpg
    97.6 KB · Views: 131
  • CIMG1533.jpg
    CIMG1533.jpg
    85.5 KB · Views: 171
  • CIMG1534.jpg
    CIMG1534.jpg
    86 KB · Views: 167
  • CIMG1535.jpg
    CIMG1535.jpg
    87.9 KB · Views: 155
Either mix dish soap/water or glass cleanr and start spraying any where it could leak. Put the vent tube in glass of wter and check for bubbles from case leak. Also spray kicker seal, sprocket, shifter, oil cap, and case seam on complete engine.
 
Burning tranny fluid causes stinky white smoke..

Could the heavier viscosity tranny oil you used be masking an air leak?
 
You are doing the leak test correctly! If it held 7psi for 20 minutes -you are air tight! BTW- nice tester!
Could a wire be hanging down by exhaust or headlight wire melting, exhaust sitting on fender, stator wires? Only other plastic smells I can think of. Is that oil you are using for injection? There is a difference in premix and injection oil. (not sure that would cause a plastic smell. And the crankcase oil you use is not regular car oil right? If so drain immediately and flush with TYPE F tranny fluid , then refill with TYPE F it can be had at any auto store/walmart. Just change it regularly, I drain and fill once a month during riding season, and always fresh goes in during storage. I probably only ride about 30 hours a month.
 
slickerthanyou said:
You are doing the leak test correctly! If it held 7psi for 20 minutes -you are air tight! BTW- nice tester!
Could a wire be hanging down by exhaust or headlight wire melting, exhaust sitting on fender, stator wires? Only other plastic smells I can think of. Is that oil you are using for injection? There is a difference in premix and injection oil. (not sure that would cause a plastic smell. And the crankcase oil you use is not regular car oil right? If so drain immediately and flush with TYPE F tranny fluid , then refill with TYPE F it can be had at any auto store/walmart. Just change it regularly, I drain and fill once a month during riding season, and always fresh goes in during storage. I probably only ride about 30 hours a month.
Click to expand...

Oh man. Yeah the premix oil i use is the echo blend. Prob not for injection systems huh? also yeah its motor oil without any labeling for friction additives. I thought it yamaha said 10w30 motor oil or yamalube 10w30 without friction adds? Im gonna grab some type f from my job like you advise. i also think im gonna delete this injection system and do my own mixing. Im gonna check to see if any wires or anything else is melted. could be but the smell is really heavy when i pull the plug and smell the electrode.
As for riding. i go every weekend so id say its about 20-30 hours a month and i have been change the oil about every other week. Thanks for the advise and props on the tester.
 
Larry's Shee said:
Either mix dish soap/water or glass cleanr and start spraying any where it could leak. Put the vent tube in glass of wter and check for bubbles from case leak. Also spray kicker seal, sprocket, shifter, oil cap, and case seam on complete engine.
Click to expand...

Im gonna try this and see what happens with the clutch cover off. Also does it make a difference whether i have the oil cap on or off when looking for a leak on the clutch side? I did it both ways. same results but im just wondering if the cap seals the cavity enough to where it might hide a leak? thanks.
 
giantvt104 said:
Oh man. Yeah the premix oil i use is the echo blend. Prob not for injection systems huh? also yeah its motor oil without any labeling for friction additives. I thought it yamaha said 10w30 motor oil or yamalube 10w30 without friction adds? Im gonna grab some type f from my job like you advise. i also think im gonna delete this injection system and do my own mixing. Im gonna check to see if any wires or anything else is melted. could be but the smell is really heavy when i pull the plug and smell the electrode.
As for riding. i go every weekend so id say its about 20-30 hours a month and i have been change the oil about every other week. Thanks for the advise and props on the tester.
Click to expand...

giantvt104 said:
Im gonna try this and see what happens with the clutch cover off. Also does it make a difference whether i have the oil cap on or off when looking for a leak on the clutch side? I did it both ways. same results but im just wondering if the cap seals the cavity enough to where it might hide a leak? thanks.
Click to expand...

Wonder if the rubber boot on the plug is burning or that echo oil is just burning weird. Ditch that oil and if ya ditch the injector system, use some good "premix" klotz, maxim super m. many aftermarket oils out there. And tranny wise, for sure get some type F, or some belray gear oil. Just make sure you flush the motor oil out good!
 
slickerthanyou said:
Wonder if the rubber boot on the plug is burning or that echo oil is just burning weird. Ditch that oil and if ya ditch the injector system, use some good "premix" klotz, maxim super m. many aftermarket oils out there. And tranny wise, for sure get some type F, or some belray gear oil. Just make sure you flush the motor oil out good!
Click to expand...

after checking im pretty sure nothing is burning on the exterior that i can see anyway. im gonna get a different 2 stroke oil. as for the tranny ill switch that up too. do you think if i warm it up and drain the old then fill with new, warm up again. drain and fill a second is enough of a flush?
thanks again slick
 
You must log in or register to reply here.

Similar threads

Nathon
2005 blaster boggs and smokes
Replies
0
Views
90
Engine
Nathon
Nathon
jvigoo
HELP!!
Replies
12
Views
247
Engine
RIDE-RED350r
RIDE-RED350r
blaster_4_ever
67.25 mm bore - wiseco piston - stock bottom end - stock exhaust
Replies
5
Views
208
Jetting
blaster_4_ever
blaster_4_ever
N
1999 Yamaha blaster not starting
Replies
1
Views
659
Engine
Whatsup2day
W
D
Lots of white smoke, no power!
Replies
2
Views
606
Engine
Larry's Shee
L
Top Bottom
Back