Suzuki 450 GSL 1982 running lean question

I just bought a 1982 450 GSL twin for the wife to learn to ride.
Always started and dumped fuel after shut off. Fixed that issue by
draining the crank case and adding new oil and dismantled the carbs
and cleaned them. It bogs when giving it throttle or under power. It
only will run consistently while choke is on, and the plugs burn
white. Has a tendency to gradually climb in rpms while idling.

How can I check the fuel petcock for proper gas flow to carbs?

Or other issues to look for causing it to run lean?

 

Doubtful that fuel flow is the problem but just observing the flow from a
disconnected house should be a sufficient test for that. It doesn't take a
lot to run a bike.

Most likely cause of your LEAN problem is: Rubber boots between carb and
engine are loose or cracked......or there is a vacuum leak elsewhere.

Did you drain the tank when the carbs were cleaned? Bad gas (water)?

Unless you paid particular attention to the jets (reamed out with a fine
wire) it's possible they are still clogged.

Of course, it's always possible that the carb(s) weren't put back together
properly ! ;-)

 

Am enjoying these informative posts from Albrecht about carbs (they seem
knowledgeable and logical too) even if the people with the carb problems
might not be enjoying the problems. (Am saving them all so that I can
adjust neighbour's old 125 properly the next time she brings it over.)

Just wondering if there is a typo':

Should the above say "constant VELOCITY diaphragm ..."?

thanks,
p

 

I've been told that if the screw is on the air side of the carb', it is
a pilot air screw and that if it is on the engine side it is a fuel
mixture screw (ie., adjusts the amount of mixed fuel/air entering the
engine from the pilot hole that is added to the amounts that always
enter through the other holes). Just wondering if there are some bike
carbs where this isn't true?

thx,
p

 

Thanks.

p

 

I just asked what time it was and he proceeded to tell me how to build a
clock !!! ;-)

 

I don't think it was me, even though it does often take me a year or
more to understand even simple ideas (and I like also to stay in the
shade). I think I may be getting the drift if you mean that at a speed
the carb' is designed to be most often operated at the amount of vacuum
will be fairly constant whereas that might not be so with the older
throttle-slide type of carb (if I've got the name right).

Anyway, I certainly wasn't criticizing the lingo, your posts seem very
helpful to me.

p

 

The interesting thing is that he doesn't actually know much about the
bikes he's looking at either. The instrucvtions to turn the fuel tap to
ON or RES to flow fuel are meaningless because the 450L does indeed have
a vacuum tap and so won't flow duel unless the engine is running.

All he does is look at schematics and (usually) draw a correct
conclusion and (occasionally) draw a completely wrong one. His actual
experience of motorcycles is very small.

 

Ahem. Glass houses......rocks and all that!
Nobody is perfect, least of all YOU (and certainly not ME).
Vacuum operated petcocks have a PRIme setting which do indeed allow fuel to
flow while the engine is OFF.

I think the information he provides is helpful (100% accurate or not) but
finding the piece(s) that are pertinent to the original question is a lot
like culling through a Google search that returns 100,000 hits !

 

Er, yes, but the Prime Setting is not the On or Reserve, is it???? And
it won't flow fuel on those settings unless the engine is running....

 

True, unless you're sucking!