DKL PVC manifold + 2-1 adapter + Stovebolt carb

[esturdivant]

So i've been fiddling with this oldwing off and on for a while and never could get my Stovebolt carb idling well, esp when cold. Prev manifold setup was VW type 4 plenum, PVC runners, Stovebolt new weber 2 bbl carb. I suspect tiny air leaks were culprit.

So i thought, simple DKL manifold + 2-1 adapter would be better than my crappy PVC runners with the VW plenum.

So here i'll be tracking progress of the DKL version plus 2-1 adapter.

 

[esturdivant]

Pic of the floor flange, 2+1. Bolted up fine with no mods, with gasket and washers on the bolts.

It'll be a while before she runs. The fuel pump decided to pee gas on the ground so i need to get a new one on order. Plus i have to travel for work...

 

[joedrum]

ok ..explain more on failure to idle ...ive done a lot to my carb to lean it down low at idle and off idle ...might be a lot of carb in this mix ...at not getting idle

 

[esturdivant]

Yep. Possibly could also be carb related as it is still unmodified. First thing i wanna do is have a manifold i can be confident in. Just wasnt happy with the seemingly flimsy construction of prev version, though the carb spray test said no leaks.

Also the fuel pump was weak, so before I start to mod the carb I wanna make sure everything else is solid.

When I took apart the VW plenum last night, the runners/plenum were both wet with fuel. The wing hadnt been ridden/run in several days. So yes the carb is prolly too rich at idle.

Once I get new manifold together, ill review how it runs and post results

 

[slabghost]

Ignition has a lot to do with running across the board including idle. Be sure it all works and you have nice fat sparks. Weak spark at idle and no carb / intake setup will perform right.

 

[esturdivant]

Yep also planning on getting new coils and wires in the near future.

The guy I bought this wing from hadnt really ridden much and I could tell it had been sitting a while.

Ive already done the water pump and timing belts.

 

[esturdivant]

Update...

With the DKL manifold version I'm still experiencing the same symptoms of the last manifold setup (which was a Type 4 VW plenum + PVC runners going into the factory elbows). Idle speed screw is not out much, lost track of where idle mix is, but it's not out too terribly much. here's a quick video. no vacuum/air leaks anywhere - as tested by the carb cleaner spray on ALL the connections.

basically - symptoms include: I give it a heavy amount of throttle, and it lags and then revs. the slower I ramp up the throttle, the better it revs up (doesn't want to lag as quickly).

I haven't replaced coils yet, but it seems fine to run as is. all cyls have good spark.

BTW - after this video i adjusted the idle down to ~1200 or so. below that it seems not too happy. After the adjustment (of the mix screw) the lag seems a little less apparent, but still there.

It does seem like this this is too rich at idle, as joedrum and others have suggested. (Many thx to joe btw for all the work on this carb). I think maybe the off-idle lag is b/c of being too rich idle circuit?

Should I drill a hole in the primary throttle plate? seems kinda risky if that don't work?... but i guess throttle plates are easily replaceable....

I also replaced the fuel pump with a new OEM mech pump.

https://youtu.be/AepfHev0row

[video]https://youtu.be/AepfHev0row[/video]

 

[joedrum]

hmmmm eric it sounds like the power valve these carbs come with is flooding the the already to rich idle ... just a guess really not much to go on there ...as far as throttle plate goes a hole can be filled if not good ...

 

[esturdivant]

cool thx joe. how does the air cleaner bridge come off? looks like it's riveted in?

 

[Ansimp]

joedrum » Mon Feb 16, 2015 10:46 am[/url]":2p99cpop]
hmmmm eric it sounds like the power valve these carbs come with is flooding the the already to rich idle ... just a guess really not much to go on there ...as far as throttle plate goes a hole can be filled if not good ...

+1 on way too rich

 

[joedrum]

esturdivant » Sun Feb 15, 2015 8:52 pm[/url]":195iynxa]
cool thx joe. how does the air cleaner bridge come off? looks like it's riveted in?

sheesh i cant remenerber how the bridge was on ....my memory sucks at times especially in the morning LOL..but i needs to be gone for me as it in the way to get at carb jets........i personally dont use this at all ....my air cleaner is going no where unless it can take the false tank with it :hihihi: coffee please

 

[dan filipi]

My 32/32 came with a pin that slides out then the bridge comes right off.

 

[AApple]

joedrum » Sun Feb 15, 2015 6:46 pm[/url]":3pjmw67g]
hmmmm eric it sounds like the power valve...

+1

 

[joedrum]

the power valve is not a huge hurdle to eliminate ... there others who seemed to do fine with it in place ...that simply not the case for me and my build ....maybe someone with power valve in place might post their thoughts on how theirs is running ... opcorn:

 

[sgq700]

mine is out of the box as Tom sent it to me with the exception that i only run the 1 bbl(removed the arm to open the 2ndbbl as i don't need it) How ever, my intake is home made and different than most, mabey that is why mine worked great as shipped?? We all have djfferent set up's so it's hard to say what will work with each different design!

 

[esturdivant]

sgq700 » Mon Feb 16, 2015 5:25 pm[/url]":yu6w12v0]
mine is out of the box as Tom sent it to me with the exception that i only run the 1 bbl(removed the arm to open the 2ndbbl as i don't need it) How ever, my intake is home made and different than most, mabey that is why mine worked great as shipped?? We all have djfferent set up's so it's hard to say what will work with each different design!

Thanks, so no mods to the carb? What's your manifold like?

 

[ekvh]

Total rookie to the single carb, so what I suggest should be taken with a grain of salt. Since you have the same symptoms with both carbs, maybe you should double check ignition for possible weaknesses as Slab suggested. I'm sure you've read the posts here and everyone does things a bit different. I have a 32/36 I hope to use this summer. I was studying it a little tonight. Pretty simple but a lot I didn't realize. One thing Joe did on his was to remove the powervalve. I think the way it works is, there is a spring loaded jet in the base of the fuel bowl. It won't allow fuel through it with the pin up. It is up when there is enough vacuum to lift the power valve up off the pin of the jet. When you crack the throttle you encounter low vacuum which lowers the power valve down on the pin of the jet which opens fuel jets to allow a richer mix to be drawn in and up through the "y" shaped feeders above the venturis. On mine, the one to the secondary side is plugged. I believe this is what Joe was alluding to on the previous page. He removed the valve, I think. As I recall one of Dans carbs the pin and jet wasn't sealing properly and leaked constantly. Killed his mileage and made tuning a nightmare.
A simple attempt for you would be to remove the top and then remove the power valve with the three screws. The jet should stay closed and allow you to see if throttle response is any better. The position of this jet does leave it very vulnerable to any contaminants to wedge it open.

Seems like where you're at is where most single carbers are and they either live with it or switch back to stock. I am curious how any others have done as Joe did?

 

[esturdivant]

good info guys. Thanks evhk. working on this bike is slow going for me, between work and the fact that this bike is sitting at my mom's house. dont get much time these days to mess with it.

anyways - i'm still going to order coils and wires, as they're unknown age. And the power valve option I think is the first place I'm going to start to see if I can lean out the idle circuit.

 

[esturdivant]

ok - just got around to taking the enrichment valve apart and it appears that there's a pretty simple vacuum port that you can plug to disable this thing. this is just the cover and diaphragm popped off. appears that it's a pretty simple vacuum port that operates the diaphragm. sooo if I plug this port - this should disable the valve, right?

can't test it now...need a new battery...

 

[joedrum]

ok we got the 180 degree thing going on ....plugging the vacuue means no vacuum ....same as low vacuum ...you have just guaranteed fuel flow ...not stop it .... the pin pushes valve open ...you remove the diaphragm and it should stop flow ...but its not a very good valve set up ...how its set up .....i ended up really shutting down with epoxy once i was for sure i didnt want it