85 Magna starting problem

 I have an 85 VF700 Magna.  It had been sitting a while when I got it and
never ran well due to dirty carbs.  I finally pulled them off and cleaned
them.  It runs perfect now but its very hard to start.  When I put the choke
on it starts and runs for 1-2 seconds then dies.  It didn't do this before I
cleaned the carbs.  The only way I can start it is without the choke which
takes a while.  Any ideas what it could be?  Is my choke cable out of
adjustment somehow?

Richard

 Richard Slay wrote:

Check the idle adjust. Engine might not be getting air.

 


Constant vacuum motorcycle carburetors are different from car
carburetors.

They don't have a plate type choke like a car. The "choke" on a
constant vacuum carburetor is a little valve in a  bypass passage that
goes around the throttle butterfly.

When you pull the choke knob out, or move the choke lever, you are
opening that little valve, there is one in each carburetor.

But, for the "choke" to work, the throttle butterflies have to be all
the way closed.

So, try turning the master idle knob down as far as it will go.

That will increase engine vacuum so the engine can suck gasoline out
of the float bowls through the little valve.

When the engine starts, hold the throttle open a little bit until the
engine warms up, and then readjust the master idle knob.

If you're *still* having problems, you need to clean out the
carburetors better.

I use Berryman B12 Choke and Carburetor Cleaner.

You need to get squirt the B12 into the smaller hole in the inlet bell
of each carburetor/ That's the pilot air jet. You should get a strong
spray of B12 out the idle jet, out the three transition acceleration
ports next to the throttle butterfly, and out the
single idle mixture port downstream of the transition ports.

You may have to remove the idle mixture screws for cleaning, They are
usually concealed behind EPA anti-tamper plugs.

I have described the procedure for removing anti-tamper plugs many
times, you can google rec.motorcycles.tech for that.

  >> I have an 85 VF700 Magna.  It had been sitting a while when I got it
 >> and never ran well due to dirty carbs.  I finally pulled them off and
 >> cleaned them.  It runs perfect now but its very hard to start.  When
 >> I put the choke on it starts and runs for 1-2 seconds then dies.  It
 >> didn't do this before I cleaned the carbs.  The only way I can start
 >> it is without the choke which takes a while.  Any ideas what it could
 >> be?  Is my choke cable out of adjustment somehow?


I found the problem.  The vent tube near the end of the airbox that looks
like an umbrella handle was pinched off.  When I fixed that everything
started working correctly.  Gotta be more careful.  Thanks for the info
though.