CrankShaft Seal Info

Hey guys, got the motor all buttoned up and running great! Before replacing the valve guide seals, valve lapping, new piston rings and cylinder hone, the crankcase breather would smoke pretty bad and stall out at idle when hot. It had the proper amount of oil in it as well. A mechanic friend of mine told me that the crankshaft seal could be bad ( I checked and it did have signs of oil around it behind the pulser) and that if it is bad, it will allow air to blow by it and push any oil out the breather. The bike most likely did sit for a very very long time before I purchased it. Can you just replace the crankshaft seal by pulling the old seal out and taping in the new one? Or is it a split...? There isn't a ton of info out here on this. Also it stalls out at idle after it is nice and hot, he said another sign of it getting too much air..??? It is a 1981 KZ750LTD 4 cyl. Thanks. I have a video of it stalling out and the smoking I'd be happy to upload too.

Your friend is wrong. Can you put up the video?
Steve

I'll post it up in the morning

Heres the video. As you can see the breather is smoking pretty badly. I accidentally cut the video short, but literally right after the video ends, the bike stalls out. The electronics i.e. coils, etc... are all ok. Coils don't seem to be shorting out, nothing turns off! Very strange behavior. Bike isn't running rich either, more on the lean side. Thanks guys!

It's not the seal.

You got no airbox and it sounds like an open pipe. Ain't gonna run for crap like that unless get some quality pods like K&N's, not junky Emgo's, and a proper jet kit...and a muffler.

I do have K&N pods, just not on in the video. Along with a Kirker exhaust with shorty tip. The carbs have a dynojet kit and have been set to accommodate the filter and exhaust. Makes no difference with the filters on or off for the smoke/stalling issue. Thanks!!

It's not the seal.

You need to put the K&N's back on. And make sure they are clean and oiled.

Try tweaking the pilot screws to see if that smooths out the idle. Then sync the carbs.

When was the last valve adjustment?

Same time as everything else. Just wrapped it all up today. All 8 valves are right in spec. I'll oil up the K&N's too. Thanks

Ok, so on the crankshaft seal on the RH side, I am guessing that is a split the case type of replacement?? Thanks guys.

your bike sounds like 2 cylinder engine, put filters and mufflers on and do sync your carbs.
Are all header pipes hot when running? Float bowl high ok? Pilot screws set to reference adjustment?
Intake boot sealed proper?
Do this first before splitting the case,step by step.

If the seal is not leaking a bunch of oil LEAVE IT ALONE. It has nothing to do with engine performance or your blowby problem. Your "mechanic" friend is an idiot.

Sounds good guys. I will leave it. I'll toss the filters back on. It does have an exhaust on it, It has V&H headers and a shorty muffler with no silencer. New intake boots replaced about 6 months ago. All pipes are running good. 3/4 are running the hottest, 2 was pretty hot and 1 was past warm. All 4 sizzled water when sprayed. Pilot screws set to what Dynojet recommended with the according jets and filter/exhaust setup. I'll spend some time with the bike. Just odd how it dies. I think the smoking can be resolved by a good hot long run. Thanks guys as always.