Bringing a '81 750 back to life

[Max]

I bought the bike on Friday and spent a good part of each day so far trying to revive it.

I originally had some electrical problems but got those sorted, I cleaned the carbs as per instructions on Basscliff's site, put in a new set of plugs, and changed oil and filter.

Before the oil change (yesterday) I started the bike for the first time. After it warmed up I was able to adjust idle and it ran quite smooth (with air box but no filter, (smoking from left pipe)), a few minutes later once the bike was really starting to get warm it started to smoke more and out of both exhausts. I was running the bike on a temp tank (20oz water bottle, half full) since mine is rusty and needs a clean. I ran the bike until the bottle was empty and was starting to be starved of fuel.

What is causing this smoke?

Before being parked for a year bike had fresh (200mi) valve adjustment (have receipts from PO)

The temp tank was already hooked up for about 24hrs previously to the first start, tank had approximately 10oz of fuel in it, fuel level did not appear to decrease overnight. As DanTheMan suggested on my previous thread (http://www.thegsresources.com/_forum/showthread.php?t=167175&page=3) fuel could have leaked into cylinders and into oil.

This brings me to mu next point; which is that I did an oil and filter change today. After the service I ran the bike but I only had enough fuel to warm it up, but as it was getting warm it started to smoke a little from the left pipe. I did not have enough fuel to investigate further but I assume that the smoke would have increased.

Could it just be that there is something in the exhaust?

Could it be maladjusted carbs?

Opinions please!! What could it be???

I am still waiting for the air filter to arrive but will put it in as soon as I get the chance, air box is tight and has all fresh rubber + fresh intake boots.

Thanks,
Max

P.S, It wasn't running as smooth today but that could have just been from lack of (inconsistency) of fuel.

 

[spyug]

Do you know how the bike was stored? Did the PO "fog" the cylinders ( i.e. oil them). What cooler was the smoke? It could be oil burning off.What was the air temperature at the time? If it was cool sometimes smoke is more apparent and you might see more of it if the choke is on full. Do you smell gas? If so, you might be running too rich. Lots of possibilities

Give us some more detail and we can get a better feel for it.

Cheers
Spyug

 

[Max]

Do you know how the bike was stored? Did the PO "fog" the cylinders ( i.e. oil them). What cooler was the smoke? It could be oil burning off.What was the air temperature at the time? If it was cool sometimes smoke is more apparent and you might see more of it if the choke is on full. Do you smell gas? If so, you might be running too rich. Lots of possibilities

Give us some more detail and we can get a better feel for it.

Cheers
Spyug

I am not sure is the PO fogged the cylinders, but I suspect that he did.

I would guess that the outside temp was 45-50 degrees.

The smoke was a thick white color, I don't think that I an running rich as there is currently no air filter in the bike.

 

[Max]

on second thought, (after taking it for a short ride) the smoke does look just a little blue, but only in the sunlight, definitely not anywhere near a two stroke though.

While cleaning the carbs i noticed that the one on the left was very dirty (full of black gunk), and I think the only reason the bike smoking out of the right exhaust is because it is connected to the left one. I think all of the smoke originates out of one of the two left cylinders.

The bike does smell a little rich, but that's funny because there is no air filter on it.

Idle is pretty rough but I think that is due to no filter also.

Thoughts?

Thanks,
Max