Single Carb. Conversion, VW Plenum & Modding, the OEM Manifolds

[westgl]

It kind of seemed like the speed of the air/fuel charge fell flat on its face.

It rode Like the OEM Stock 4carb rack Bike did.

Away from a stop, you have to rev it up a little to get away from a dead stop.

Dont get me wrong it ran good No bogging or flat spots any where, and power was good, but it lacked that throw you back in the seat high powered Torque, like the newer Corvette have.

It was very much like my GL1100 with the 4 carb rack on it.

Also I noticed that I had to use the secondary more often, to make it go, since the down low torque was not there any more.

 

[westgl]

If it is 1.400"

Then that is even worse, I think reducing the plenum outlets is only going to help, as we are getting a pulseation slow down speed up, it will do that on it's own we dont need to help by having the plenum larger than it has to be.

I have the tubes that go into that plenum out let I will go grab one and measure it.

It will give me the ID and OD of the Plenum, the tube was from the Type IV manifold, it came with it.

Now if I can find it, after the move?

canuckxxxx » Tue Oct 01, 2013 6:29 pm[/url]":1lnf227o]
Mine measures 1.4" or slightly larger than 1 3/8".

 

[westgl]

Ok found the tubes,

Yes they are 1.400"ID cause the tube that fits in there is 1.400" OD and 1.300"ID, the iD of the tube is irrelevant different application.

So 1.400" ID of the outlets Now,

But reduce all the Outlets down to 1.125" ID. I think would help a LOT!!

Then a smooth transition into 1-1/4" ID

That is .275" in diameter reduction, in the outlets.

That is significant

 

[canuckxxxx]

If you use 1.25" schedule 80 aluminum pipe it is 1.25" ID, 1.67" OD. I would suggest machining the .5" or so of the end down to 1.375-1.4" so it will go into the VW spigot. The outside diameter of the spigot is about 1.625" so a rubber coupler with hose clamps would fit nicely if you could find one with a 1 5/8" ID. Or you might be able to solder the tube into the VW manifold. I wonder if there is an epoxy that is fuel proof.

The other end of the tube could be machined to the shape of the OEM carbs where they fit into the rubber coupler. With the grooves etc.

Brian

 

[westgl]

The inside of each outlet is over 1" long? I am guessing, that is the part that is machined open x 4ea

The Outlets are .275 ea x 4, larger than they should be.

Over all I reduced my 1-1/4" ID down to 1.140" id x 1-1/4" long per hose runner

At 4-1/4" OAL for the hose Minus the 1-1/4" long reduction to 1.140"ID out actual length of 1-1/4"ID hose

That is each hose is actually only 3.0" long at the full 1.250"id.

 

[82a]

pix on diff engine but used for a generator, so a steady rpm

 

[westgl]

I think being able to remove these tubes is proving beneficial.

As we may need to tune or replace parts, right now it is like legos,

If two pieces become one, or worse 5 pieces become one, then you loose the adjust-ability.

I may love my bike to be very torquey, Tony, may like his bike for mid to top end power, cause he is a adrenaline junkie.

Tony, loves that adrenaline rush, and bugs bouncing off of his teeth at high speed, or crushing between them, for a snack for later .

It seemed to me the engine did not have to work hard to run great.

 

[westgl]

That air plane engine, Look how small the plenum is kept, in comparison to the tube size, but you cannot see in side the tubing to see if some kind of a reducer bushing lurks inside

We are close, and just need to scale back some and add a little tune in the Plenum outlets along the way.

I think when i measured the Outlets before they were machined down deep into the outlets, they measured either 1.0" - 1.125" ID

I will maintain that smaller ID in the plenum outlet, then open to 1.250" the length of the runner.

 

[slabghost]

I have type 1 vw intakes for the single port heads I plan to try here. ID is 1 3/16" to each head. That fed two cylinders at either end. Seems to me 1" ID plenty but only time will tell. I haven't yet found time to get started modding these to fit.

 

[joedrum]

I have no idea how big that motor is but it looks a whole lot bigger than an oldwing ...it looks like icing would be a big deal ...but im sure its not cause not one thing to combat it ...I think we put to much into the boogie syndrome of things to worry about .....im glad we are close with everything ...this is no joke here ....seems to me ..ive gotten two carbs to work rather good ...I like the rubber hose deal as it was always my attention for this to be easy and not a one piece spider of a deal .....im thinking that when the bigger hose get to 90 just before head turbulence is created...the smaller 1 1/4 ID hose lessens this id say ....oldwings were working on are made to perform across the rpm zone ...although Honda miss this big time on stock setup ...oldwings have got to be on the lowest end of good performing stock setup carburation ...there are so many bikes that are so much better ...but oldwings are bullet proof lower ends ....so if Honda did so poorly ..we cant expect to just throw something together and it work across the board in the rpm zone

I like the mod of the intake horns to straiten hose up westgl did ....

I think all the high dollar bs metal of making this mod cost as much as stock carb rebuild defeats the purpose of this mod ....some might not look at the hose as stout enough ...but westgl has already fix his in the center to stabilize and heat some .....I think people who nay say about rubber runner are just talking out there rear end to justify there huge expense had a reason when it don't ....people who are selling this crap have to have a sales pitch....

as it has proven so far here it is a down grade in performace so far to have the metal runners ...idont care what the claims are plus at 10 times the cost it just ridicules .....

 

[westgl]

I did check the runners temps, after bike was up to, NO Temp.

Runners were ambient, VW Plenum was ambient, to maybe only Slightly cool by a couple of degrees.

That was at 52 degrees, and after the ride.

 

[joedrum]

hmmm yes I cant wait to test ride again ..simply stated im broke right now ....but it will change soon ...hooch is on the smaller weber carb right now like westgl ...when I rode it ...it was sweet ....im not looking to change much ....just want to really get down and test ride it ...cold comong so icing will be in play lets see what its got to mess things up ...is what im looking to see ...how big is this problem ....

 

[westgl]

Yes Joe,

I am sure that is the question, in all of our minds,

What or how will this effect, and what is the setup you, or i, would be using, at the time of this cold running test, as well as out side temp, humidity, is also important, as i may be in a dryer climate that you are, or vice versa.

Someone Like Dan, this is a Mute point, because the cold season is from December 1 to December 2, and rainy season is on February 4, for 1 day.

Over exaggeration, I know, But Cali, has many more good riding days, only problem, is TOOO much traffic.

Dan, what about a large Jousting lance, maybe a mid-evil Mace, for when traffic gets too close and cant hear your horn.

Oil tank that drops 2 quarts of oil behind the rear tire, out on the road,

Or a spark plug in the exhaust pipe near the end with a fuel Injector screws into the exhaust, flip a switch and shoot out 6 ft of flames

joedrum » Wed Oct 02, 2013 7:22 am[/url]":1j7ahus5]
hmmm yes I cant wait to test ride again ..simply stated im broke right now ....but it will change soon ...hooch is on the smaller weber carb right now like westgl ...when I rode it ...it was sweet ....im not looking to change much ....just want to really get down and test ride it ...cold comong so icing will be in play lets see what its got to mess things up ...is what im looking to see ...how big is this problem ....

 

[westgl]

It is Close!

Rev.3 will be better than Rev.2, for me anyway.

I dont normally ride my Oldwing above 85mph, as I try to avoid tickets, or jail.

But i do like lots of Useable torque!!!!

I want to get up to 85mph FASST!!! a top speed of 100-mph is fine for me.

Now just to tune the runners and plenum outlets,

I will pick up some more tubing, today.

 

[canuckxxxx]

westgl » Tue Oct 01, 2013 7:45 pm[/url]":1p8slql5]
Ok found the tubes,

Yes they are 1.400"ID cause the tube that fits in there is 1.400" OD and 1.300"ID, the iD of the tube is irrelevant different application.

So 1.400" ID of the outlets Now,

But reduce all the Outlets down to 1.125" ID. I think would help a LOT!!

Then a smooth transition into 1-1/4" ID

That is .275" in diameter reduction, in the outlets.

That is significant

West,

Where did you get the 1.4" OD tubing from?

Brian

 

[westgl]

The 1.400" tubing is the Type IV VW Plenum tubing that I bought with my manifold.

 

[westgl]

I bought some tubing today

Rev.3, Plenum Chokes
I bought some tubing for the Plenum chokes.
1.300" od x 1.050" id Plenum Chokes

Rev. 2 tubing & Rev. 3 Plenum chokes together
I wanted to do a test with tuning, so i put in the new plenum chokes, with the 1-3/8"ID tubing, much more low end torque now, there is some slight hesitation, No bogging, but all power is improved, from Rev.2

So tomorrow I will put the last tube runners into place.

Making Rev.3 Complete,
New tube Runners
1.490" Od x 1.250" ID

 

[westgl]

I have to say that Mid to top end was really good,

With the new plenum chokes torque is much improved.

I think with the New tubing, it should be great.

I had reducers in the hose in rev.1 that reduced the ID down to 1-1/8" ID, in some places and 1.250"ID in other places.

The added Torque that i got from the Plenum chokes was really good.

I made the Plenum chokes 2.0" long, they fit inside the plenum runners.

Tomorrow I will shorten the plenum chokes to 1" long, and install the 1-1/4" ID runner tubing

Rev. 3, should have the full torque of Rev.1, maybe More torque than rev,1, but also have more Mid range & top end than Rev.1 had.

If i can get rid of that slight hesitation, I will be very happy.

 

[joedrum]

sounds good westgl ...sheesh we can all see now .. and this forum has really brought it to life ...there a lot more here going on than just right size carb .....its about tuning the manifold to make carb and motor work together the best they can ....great report

 

[westgl]

Just for the halibut, Cause i love halibut.

The Stock, matched tube Runner size, for the Type IV manifold plenum.

Those tube runners are suppose to fit a 914 or type III & IV VW pancake engine.

Tube size that came with Plenum, Is 1.400" OD inside outlet x 1-1/4"ID inside of plenum outlet, then out side of outlet, the tube tapers down (like a funnel) to 1-1/8" OD the rest of it's length, and is maybe slightly larger than 1.00" ID.

These tubes could be used, possibly, but they would have to be built up at the Oem manifold end, then tested.

With the 2ea Oem manifolds Modified, twisted to point directly at the heads intake port, a straight tube like this could be used, If i did use these tubes i would leave the runner as long as possible and run these runner into the oem manifolds past the rubber maybe touching the alum. inside of them, then wrap the exterior of tube with gorilla tape to take up the slack/difference between the tube and the Oem rubber manifold for making a good seal.

Torque would be impressive.

I wonder where power would be over all, in mid to upper?

But testing would need to be done.

westgl » Wed Oct 02, 2013 5:54 pm[/url]":1sdlggdf]
The 1.400" tubing is the Type IV VW Plenum tubing that I bought with my manifold.