Excessive Smoking - are my crank seals knackered?

[n8balls]

Hi guys

I’m sure this is one the main questions people ask but I have done a lot of searching on the forum and I’m keen for any further advice that people can give

Background
Picked up a GT750A that has been stored for 25 years (20,000kms). It’s generally in very good mechanical condition but I’m worried about the crank seals
I put petrol/2 stroke oil mix in block for 3 days before starting it to attempt to soften/condition the seals
I cleaned/serviced the carbs, oil pump, cooling system
It starts very easy but smokes excessively from all exhausts
I have only run it long enough to get up to temperature on about 3 occasions (maybe 20 mins in total)
I can't take it out on the road for a blast to see if the smoke clears out becasue the bike is unregistered

My questions:
How long should it take running in the garage to the smoke to clear (after having the case full of petrol/oil) or does it really need to be ridden under load to see if it clears out?

Could something else, like faulty check valves on the on the oil injection or SRIS issues lead to excessive smoking?

cheers, n8

[tz375]

I'm pretty much sure that you can run it until it runs out of gas and it will not get hot enough to burn all the oil out of the crankcases or pipes. It really needs to be ridden up higher in the rev range to clear that backlog of old oil.

A good start might be to remove the SRIS valves and let the cases drain out any surplus oil and then replace them and run the motor.

[oldjapanesebikes]

I'm pretty much sure that you can run it until it runs out of gas and it will not get hot enough to burn all the oil out of the crankcases or pipes. It really needs to be ridden up higher in the rev range to clear that backlog of old oil.

+1 to that.

[n8balls]

Thanks! So it looks like a catch 22 ensues - I can't take bike out on the open road to stop it smoking because it's not registered, but I can't get it registered until it stops the smoking...

I'd take it out for spin with the number plate from another bike but a smokey two stroke would be like a red rag to the filth I suspect...

cheers, n8

[barko1]

Background
Picked up a GT750A that has been stored for 25 years (20,000kms). It’s generally in very good mechanical condition

cheers, n8

Send it over here, I'll blast it down the road Just curious but do you mind saying what the dear cost you? I was in AU last year (rode to Perth from Melbourne) and was surprised as to how expensive bikes were BTW I named my X-6 Sheila.

[oldjapanesebikes]

I can't take bike out on the open road to stop it smoking because it's not registered, but I can't get it registered until it stops the smoking...

I'm curious - what's the connection between the smoking and getting it registered ?

[n8balls]

I'm curious - what's the connection between the smoking and getting it registered ?

I'm assuming the cops aren't going to say it's a road worthy vehicle if it's blowing smoke like cheech and chong, but I've never taken a bike over the pits before

As for the price, I paid 2,500. I've seen a couple of restored models advertised for 10k here, not sure if they sold tho. I'm not looking to make restore and sell it, I just want to get it on the road and reliable without spending too much - but that probably depends on crank seals

cheers, n8

[oldjapanesebikes]

If it were a 4 stroke, then sure - there is a problem. Its a smoker - so it smokes after a prolonged storage time or when its cold. I admit I got pulled over once - first ride of the year, and I opened it up a bit right in front of a cruiser ! I expected trouble when he disappeared completely in the cloud but once he knew what it was, all was fine. And after a couple of miles it was blowing clean so no issue.