ralpharama
XS650 Member
Earlier this year I rebuilt an XS650 motor for a customer that had undergone a whole heap of unkindness in it's long life.
I replaced all the oil seals, gaskets, 'o' rings etc with new and all gaskets were seals with Wellseal It's now out to fourth oversize and pulls really well with bags o torque
I built it into an early Uncle Bunts soft-tail framed chop as requested - see pic with client below -
I have fitted a catch tank which is fed from the breather, which you can see in the photo.
After less than thirty miles it has developed a bad oil leak from behind the ignition pickup. The bloke is supposed to be having some fun riding it around before the proper paint job and a chance to let stuff bed in. He tells me a lot of oil is coming out of the cover behind the pick ups (points replace with boyer branson electronics ignition). I'm wondering if this could be as a result of crankcase pressure building up and am wondering if I need to make some form of custom airbox for it, so that there is a negative pressure on the breather when the pistons go down, thereby reducing crank case pressure on the seals.
What made me question this is the copious oil flow past the seal and the fact that the engine had two large bore breather pipes going to the airbox when the bike was standard.
Has anyone had issues with crankcase pressure causing oil leaks from seals?
Many thanks
Ralph
I replaced all the oil seals, gaskets, 'o' rings etc with new and all gaskets were seals with Wellseal It's now out to fourth oversize and pulls really well with bags o torque
I built it into an early Uncle Bunts soft-tail framed chop as requested - see pic with client below -
I have fitted a catch tank which is fed from the breather, which you can see in the photo.
After less than thirty miles it has developed a bad oil leak from behind the ignition pickup. The bloke is supposed to be having some fun riding it around before the proper paint job and a chance to let stuff bed in. He tells me a lot of oil is coming out of the cover behind the pick ups (points replace with boyer branson electronics ignition). I'm wondering if this could be as a result of crankcase pressure building up and am wondering if I need to make some form of custom airbox for it, so that there is a negative pressure on the breather when the pistons go down, thereby reducing crank case pressure on the seals.
What made me question this is the copious oil flow past the seal and the fact that the engine had two large bore breather pipes going to the airbox when the bike was standard.
Has anyone had issues with crankcase pressure causing oil leaks from seals?
Many thanks
Ralph