73 GT550 / Oil in Pipes and smoke

[mrmach5]

I recently purchased a very nice 73 GT550 from a Gentleman in Michigan. It had a restoration done by the previous owner in Eu Claire Wis.
I had it shipped and picked it up yesterday at a warehouse. The bike was better than the pictures, so was really excited getting it. it was palletized and I noticed lots of soot black oil on the pallet? When I got home , more on my trailer. I started it up outside and it fired, but blowing out this black crap from any exhaust joints and heavy smoke out of the pipes. Reved and Idled fine,,, suprised it didn't foul the plugs an quit.
Before purchase the guy sent me a start up video, and the bike sounded great and no smoke. He told me while he had it , it would smoke just at little on start up then clear out. So what has changed in a matter of weeks???? I've checked the gear oil to see if there was any contamination it it looks perfect and has no odd smell. I've checked the oil pump adjustment and it's dead on. I notice there is no off position on these petcocks , just on ,reserve and prime. Could it have flooded the crankcase while shipping??? I'm grasping here ,,, Help !!!!!!!!!!!

[Indy650]

the oil system can gravity feed if it has a bad check valve but the oil wouldn't be able to get into the exhaust if the bike was just sitting. I'm not sure what might have caused your situation but I would recommend cleaning out the exhaust, putting them back on, and see how it runs. Also I think 73 has the sris system that helps recycle extra oil in the crankcase so if there was a build up of oil in the crankcase it would have immediately smoked out all 3 cylinders. If your lucky you might just need to rip it down the road and open it up really good to clean it out. Another thing make sure the oil pump is connected to the throttle and moves with the throttle. I'll see if I can find a manual online incase you don't have one so you can also see how to tell if the pump is adjusted correctly.

[Indy650]

this is the best I could find but it should have the info you need.
https://www.oldjapanesebikes.com/mraxl_ ... /index.php" onclick="window.open(this.href);return false;

[dorT500]

.....noticed lots of soot black oil on the pallet? When I got home , more on my trailer.............video, and the bike sounded great and no smoke....... So what has changed in a matter of weeks???? I've checked the gear oil to see if there was any contamination it it looks perfect and has no odd smell................I notice there is no off position on these petcocks , just on ,reserve and prime. Could it have flooded the crankcase while shipping??? I'm grasping here ,,, Help !!!!

hhmmm.....crankchamber/cylinders flooded with fuel and sloshing around a bit in oily crankchambers and then in mufflers during shipment and unloading Fuel petcock issue? You may be on to something. I really don't know much about the GT550 but it did cross my mind that your early '73 may have internally vented carbs ( reference thread below)....I'm no expert on carbs either but I did think of the thread below after reading your post. I may be way off base and not thought about it enough but what the heck.....it wouldn't be the first time.

viewtopic.php?f=9&t=13482" onclick="window.open(this.href);return false;"



Hope you get it all sorted out soon and to see general discussion about the sris lines, just enter keyword 'sris' into this forums search engine. Lots of info on the early and later versions (pressed in and screwed in fittings)

[alanr]

you said revs and idles fine,just give it a good run,dont look for non existant problems.my bikes always smoke after sitting but a good blow out fixes it.if any doubt call previous owner for a confidence boost.Repeat-you said revs and idles fine.relax enjoy.

[Alan H]

It needs a 50 mile ride out of town. Do some reading too.

[mrmach5]

After sitting on my lift overnight, again oil puddles under the pipes. I was leaning toward my original guess being the petcock flooding the cylinders and into the pipes, however if that was the case the fluid leaking would be more fuel less oil. This oil is soot black and fairly thick, and does not smell like gas. I really can't determine if its's 2 stroke oil, or gearbox oil by smell or thickness. As I said the gear box oil looks perfect, no cross contamination which I would assume there would be if a crank seal blew out? Not sure were to look next? if the check valve on the oil pump was allowing oil to flow thru the system would it gravity feed into the cylinders then pipes?
Really appreciate any input trying to solve this one.

[jabcb]

I had an ignition problem on my gray GT750. It ran OK but was marking its spot with blackish crud.

Fixed the ignition problem. It then smoked so much that my driveway was getting cloudy. Everything was fine once all that muck was cleared out.

[Indy650]

Theres no way transmission oil or 2 stroke oil can get into the exhaust while the bike is sitting. I would take it for a good ride and open it up see if the smoking gets better. you could clean the exhausts out before the ride to help but I think a good ride will clean it out.
edit- it could be that the engine was flooded and raw gas got in the exhausts when you ran it briefly. that would cause nasty black fluid to drip out. Take it for a good ride and let us know how it went.

[mrmach5]

What your saying makes sense, and perhaps the petcock might be back on the suspect list perhaps causing the flooding. I'll clean the baffles out etc. then take my first ride on this bike and hope to get it cleared out. I'll be gifting my local neighbors with a complementary mosquito control service on the way out, hopefully the smoke will clear by time I get back.

[dorT500]

........ I'll be gifting my local neighbors with a complementary mosquito control service on the way out........

Not to mention the 'local authorities'.......been there.....done that.....a smoking warning from the Highway Patrol years back. He was a lot younger than the bike. I told him it was an old two stroke.........I gave him the old ' If it ain't smokin...it's broken' routine.....didn't help much. It was smoking more than it should at that time.

Good Luck, hope you can clear it up.



'Dinosaurs' (in some cases)...... working on 'dinosaurs'........two-stroke dinosaurs no less..... are we having fun yet?







Oh well......it keeps most of us out of trouble.

[jabcb]

A motor that’s smokes because its old is worn out.

Our two strokes smoke because they are vintage or antique. It smokes because that’s the way they did things back in the 1960s & 1970s.

[Indy650]

sadly most of the new generation have no clue what a 2 stroke even is... I had someone ask me once why my bike sounded like a chainsaw SMH...

[GTandcbr]

This may help to check your petcock
https://youtu.be/qWNyvjaWfz8" onclick="window.open(this.href);return false;

[Alan H]

A motor that’s smokes because its old is worn out.

Our two strokes smoke because they are vintage or antique. It smokes because that’s the way they did things back in the 1960s & 1970s.

Sorry, but that's incorrect. A 4 stroke engine that smokes has worn parts - pistons, rings, bores, valve guides, etc. Worn, not worn out and may still have lots of life left but will make less power partially due to the oil in the combustion making that combustion process less efficient. Even the type of fuel will cause smoke - diesel is more prone to that than petrol, for instance.
A 2 stroke engine has oil injected inside or at least mixed with the fuel so it HAS TO smoke as the engine lubrication is TOTAL LOSS. That's one of the reasons why a 2 stroke engine isn't twice as powerful as a similarly tuned 4 stroke despite having a firing stroke every revolution. There are other reasons also, such as charge blowby through the ports, but that's another discussion. But all 2 strokes smoke, some less than others and also depending on the oil used and type of riding done. Nothing to do with how they were - it's the design. Nobody cared about polar bears in the 60s, 70s or 80s much!