jvdavidson
'78 XS400-2E
Greetings everyone,
Having owned my '78 XS400 only since the beginning of September, I've had to do a lot of work on it in order for it to be running like a song as it currently does - this included: replaced clutch, replaced clutch pushrod seal, oil and filter change (obviously), spark plugs and wires, rebuilt carbs and balanced, adjusted valves, points, and timing, fixed turn signal switch, replaced battery, adjusted voltage regulator, replaced tires and tubes, crafted an arm for the center stand (not kick stand) as the arm was broken off. After all that work, she runs like a dream but the real kicker is that it started leaking oil - badly.
I just saw drips from the bottom of the crank case and the center stand was soaked heavily in oil so I replaced the drain plug seal and the gasket for that plate under the crank case. After doing so, I found that the leak was not resolved and it's bad enough that I will not ride this bike as the motor is pissing oil onto my rear tire. After a good looking-over, I can only conclude that the crank case has fractured at the rear-lower motor mount as there's no oil coming from further up the motor (e.g. where the case splits) and there's no oil coming from anywhere forward of this point that may be blown backward while riding.
Is a crank case fracture a common problem with these bikes? Or am I the only poor miserable sap who's lucky enough to have this problem on his hands? Unless there's some seal/gasket for something in the area of the rear-lower motor mount which gave way and the case is actually NOT cracked, I can't think of any other source of the oil leak. Currently, the frame and some years of gunk make it difficult to see the area clearly but I'm presently quite bent out of shape at this bike - it's not as if I've gone off-roading hitting colossal jumps where the engine would be jarred against the frame-mounting points and fracture - I dodge all potholes (primarily because I'm afraid of bending a rim and I ride the same route so I know where all the potholes are). Therefore, I cannot possibly fathom how this leak came about - if it's indeed a case fracture.
My present course of action is to ride it to a nearby Yamaha dealer tomorrow morning and pay the shop $90 to confirm the source of the leak for me. If it definitely is a cracked case, I'll have no choice but to remove the motor, split the case, clean the bottom half and take it to someone around here (chicagoland) who can weld aluminum then button the thing back up and try to configure some means of rubber-mounting the motor.
Thanks in advance for your feedback - it is greatly appreciated!
Best,
James
Having owned my '78 XS400 only since the beginning of September, I've had to do a lot of work on it in order for it to be running like a song as it currently does - this included: replaced clutch, replaced clutch pushrod seal, oil and filter change (obviously), spark plugs and wires, rebuilt carbs and balanced, adjusted valves, points, and timing, fixed turn signal switch, replaced battery, adjusted voltage regulator, replaced tires and tubes, crafted an arm for the center stand (not kick stand) as the arm was broken off. After all that work, she runs like a dream but the real kicker is that it started leaking oil - badly.
I just saw drips from the bottom of the crank case and the center stand was soaked heavily in oil so I replaced the drain plug seal and the gasket for that plate under the crank case. After doing so, I found that the leak was not resolved and it's bad enough that I will not ride this bike as the motor is pissing oil onto my rear tire. After a good looking-over, I can only conclude that the crank case has fractured at the rear-lower motor mount as there's no oil coming from further up the motor (e.g. where the case splits) and there's no oil coming from anywhere forward of this point that may be blown backward while riding.
Is a crank case fracture a common problem with these bikes? Or am I the only poor miserable sap who's lucky enough to have this problem on his hands? Unless there's some seal/gasket for something in the area of the rear-lower motor mount which gave way and the case is actually NOT cracked, I can't think of any other source of the oil leak. Currently, the frame and some years of gunk make it difficult to see the area clearly but I'm presently quite bent out of shape at this bike - it's not as if I've gone off-roading hitting colossal jumps where the engine would be jarred against the frame-mounting points and fracture - I dodge all potholes (primarily because I'm afraid of bending a rim and I ride the same route so I know where all the potholes are). Therefore, I cannot possibly fathom how this leak came about - if it's indeed a case fracture.
My present course of action is to ride it to a nearby Yamaha dealer tomorrow morning and pay the shop $90 to confirm the source of the leak for me. If it definitely is a cracked case, I'll have no choice but to remove the motor, split the case, clean the bottom half and take it to someone around here (chicagoland) who can weld aluminum then button the thing back up and try to configure some means of rubber-mounting the motor.
Thanks in advance for your feedback - it is greatly appreciated!
Best,
James
