Smoke from Crankcase?

Hello all, new to this forum.
Recently purchased a 1982 xj650 Seca for a pretty good price. Cafe racer inspired, took it straight to the mechanic to get things running.
Everything went well after picking it up but cut off due to the rectifier being disconnected. Reconnected that and so far so good.

had some trouble starting it again but eventually turned over. I’ve noticed that there is some smoke coming from the crankcase filter?

only happens at idle. When riding, no smoke. Is there something internally with the pistons and/or cylinders?

also will like to add that this bike came with pods on the carbs and filter? on the crankcase

Not sure why I can’t attach any photos.

Any advice is greatly appreciated.

Will take it to the mechanic next week again. Just want to enjoy a ride for today

 

Depends HOW MUCH smoke is coming from the breather.........a little bit is okay (it's normally vented thru a rubber hose back into the airbox that you no longer have, so normally, you would not notice the smoke). Even if the engine (pistons/rings) are in good shape, there is a always a bit of "blowby" into the crankcase, and the pressure within the crankcase blows any unburned vapors out of the vent (and into the airbox for re-cycling back into the engine). With pod filters, there's no place to vent that output to.....besides the atmosphere. And so you see it........

 

Thanks for the informative reply. The smoke amount is noticeable at a stop. Other people definitely notice it while at a stop light. Kind of looks like the engine is smoking. I’m not sure if that’s normal or not.

Is there a way I can upload a video to this forum?
Also not letting me upload any photos as well

 

You need to post five times before you can upload pictures. For video you can put that on YouTube for example and post the link here.

 

Got it. Thank you.

I've uploaded a video on youtube showing the smoke. This was actually right before the bike died on me. I just pulled over to get some directions and shut off.

The smoke is more prevalent at stop lights than showed in the video. any thoughts?

 

Trying to upload the link, getting flagged as spam. I'm not sure how to show you guys

 

Actually, I just posted the link to the youtube video on my status on my profile

 

https://youtube.com/shorts/AgkaAnTzbF0?si=-4Ps64Koi9qR4lJ7

 

Copy and paste the link instead. you already have lol.

 

Doesn't look bad to me, any from the silencers? You got a lot of windage in the crankcases with those pistons going up and down the bores. In fact sometimes there are oil traces in the air filter box, it is normal. You just don't see it with the bike setup as Yamaha designed it.

 

Ah okay thanks.

Theres minimal from the exhaust. Only while revving. But looked normal to me. I'll try to upload some more videos.

Couldn't get it to start yesterday. Was cranking but not turning over, which led to the battery dying. Going to get the bike inspected thoroughly next week

 

If the voltage drops below 10 volts the TCI will not work. If you get the probes of a multimeter set to 20V DC put them on the battery and press the starter button you can check the voltage drop when the starter motor is turning against engine compression. If it falls below 10V no spark.

Minimal from the exhaust is fine.

 

Got it got it. Was doing some more research on oil catch cans. Do you think I will benefit installing a catch can to reduce the smoke appearance? any benefits or drawbacks?

 

The other thing you could try is routing the breather filter via rubber hose to the back frame of the bike, under the seat and behind the rear shocks. Because my Seca had pods when I bought it decades ago, I've been running the breather filter like that for years, with no ill effects.
What you'll find with the breather where you have it, is that the oil vapor you're seeing will build up as oily residue on the lower frame near the engine, and will need washed off periodically. If you relocate the breather to the back, the vapor dissipates behind the bike rather than on it, and there seems to be less vapor emitted.
I can't speak to the "catch can kit," as I've never felt that the oily vapor is anything to worry about, provided I check my oil level as frequently as I should.

 

I had a long breather tube attached to the swing arm, ending at the rear of the rear wheel.
It was a fairly heavy breathing engine on hot days in the city, and the amount of white vapour coming out was amusing, to the point some wag asked if it was a steam engine.

 

Nice, that is another option which I might do. Since I just purchased this bike, I was worried a bit. But after research, it seems normal. Just getting those looks from people that may think my bike is on fire lol

 

Steam engine lol panniers full of coal.

 

Pipe is a good idea, never used a catch can kit.