New guy, another single carb conversion.

[slabghost]

Agree that it could be rich or possibly lean. If the carb is set up right the chill of the adapter or any other part of the intake is of no consequence. What you see outside is no reflection of the flow inside.

 

[Hyde]

Did another ride of about 80 miles today with the latest change, I removed the 1bbl to 2bbl adapter, and cut the mounting pattern for the Weber directly in the top of my intake plenum. I lost some of the big top end hit, but its much more ride able now. Im leaning towards it being lean (I still havent looked at the plugs, bad me!)

At about half throttle when the primary butterfly is fully open and the secondary is barely open there is a huge dead spot. If I feather the throttle to activate the accelerator pump, or go wide open it will pull through it ok but still feels down on power throughout the range. Also its very difficult to get rolling from a stop. I havent seen that there is any tuneability in the carb aside from the idle circuit so guess it time to start looking for jets.

Edit, also considering Picking up a VW type 4 manifold to try. My intake has a very large plenum with pretty crudely stuck in runners to the head. There isnt a very smooth airflow path there.

 

[joedrum]

hmmm i bet it is lean at the secondary ...been wanting to post here ..but been busy with my stuff ...it might be rich down low also ...the dft is famous for rich at low rpm and lean up higher in my opinion ...these carbs were set up economy car motors ...the jetting is very small in the secondary as the motor were not high rpm deals ...in the low rpm zone they are a bit heavy in jetting cause cars had power steering ..air conditioners and such...an oldwing at hi rpm demands much bigger jetting than the cars could ever need as ther rpm was is haft that of a olwing ...so jetting is a big deal...id say ...on the type4 setup ..you just cant beat it and the grab bar runners like my bike is set up with ...1 1/2" runners all the way to the head ...love this set up ....keep plugging away ill help you all i can ...

 

[Hyde]

Finally pulled a plug, definitely lean. Going to up the jets a bit and see what happens. Pulling my hair out with this thing, anyone reading this dont believe believe the "I bolted this thing on with great power and driveability, no tuning required" line a lot of guys on a lot of the sites feed you.

 

[slabghost]

We don't believe that here.

 

[Hyde]

Does anyone know where to get main jets for these? I drilled the slow jets a tiny step up each and it runs great off the bottom now, no more bogging and dying. I think the mains are too big though, hits a wall at 6k rpm and burbles. Pulled a plug and its sooty black now so looking to go down on main jet size. I think the slows are set pretty well.

 

[joedrum]

hmmm are you good with solder ..you can fill the jet and drill it smaller

 

[joedrum]

did you clean the plugs after drilling lower jets and before running ..might want to try cleaning plugs up and try again maybe to be sure the main jet needs smaller

 

[slabghost]

Langdon should have jets or you could search ebay. Or just fill and redrill as suggested.

 

[Hyde]

I didnt even think of that, may have to give it a shot. Making progress slowly but surely

 

[Hyde]

Also may try to reincorporate the 1bbl to 2bbl adapter, I lost a lot of top end pull when I got rid of it. Now that the jetting is getting better on the bottom end Id like the see how it would respond

 

[slabghost]

Adapter serves to channel flow better and adds volume to the plenum area. Both good things.

 

[Hyde]

My plenum has a pretty large volume compared the the type 4 I see most people running. Its this manifold with the 2bbl pattern cut into the top of it, I think the adapter was helping velocity though with such a large plenum.

On another note whats the verdict on the "anti dieseling solenoid" Mine has the wires cut off pretty flush so I couldnt hook it up if I wanted, but could this cause trouble getting the idle set if not hooked up? Ive heard it both ways

 

[slabghost]

Solenoid should not affect adjustments unless it is interfering with linkage movement. All of them I am familiar with simply add throttle at the linkage.

 

[joedrum]

its actuall good to have it hooked up ..it shuts the gas off when the key is off and that helps keepthe carb idle circuit from draining gas out of the blow like a siphon type deal going on

 

[Hyde]

So if it turns gas off when the key is off does that mean not having is hooked up is shutting flow off??

 

[slabghost]

Which part?.

 

[Hyde]

Ok so mine wouldn't appear to have an idle cut solenoid according to that diagram, I'm talking about the evap solenoid then #68

 

[slabghost]

Not sure if that is open or closed when not energized. If it is open or not entirely sealed it could be allowing fuel flow. Possible source for a rich condition. A few I think have removed that entire assembly and sealed up the holes with jb weld.

 

[joedrum]

hmmm thats the 32-34 dft carb and size wise is like mine ..i dont know of anyone else running it but me ...mine doesnt have the power valve and is stripped of all epa stuff ...making it a strait carb ...will be interesting to how your carb dials in on your bike ...my motor is quite different than stock oldwing motors are ...