Different carb set up on VF1000R engine

Don't forget the "truecoat" cause you gotta have the truecoat to keep away the rust.............Sorry , your throwing numbers and equations. all I can offer is some humor.....hope you get your desired effect.......

 

I like your approach with running the numbers, but I still come back to the same conclusion - you will have supply issues much lower than redline.

The stock VF1000 carbs are constant velocity type, and I assume the Kaw ones you have selected are also. Basically what you are going to do is open the slides differently than the VF1000 needs. In fact, I'm wondering if it won't be backwards: since the Kaw carbs are for a slow revving but large displacement engine the slide action could be very 'stiff'. That means it will stay closed off more than the stock VF1000 carbs would be. This is effectively making them a smaller throttle bore, which takes me back to my original point about having trouble using them.

I guess what I should have asked at first - why are you running that setup instead of the four carb VF1000 parts?

 

I just did not like the stock carbs. I did not like the complexity and those springs between the throttle shafts. I just did not like the whole rig. And I do mean RIG! Those plastic air and fuel delivery tubes with "O" rings. Really stupid. Cheeeesssshhh! No wonder the bike was only in production for 3 years. Who would want to take all that apart just to change the jets.

BTW That is why the Holly car carbs were so popular. The jets were very easy to get to and change.

Now all the motorcycle engines are inline v4's with four inline carbs. Smart. Much better.

 

I'm with Donald on this one. A V4 setup with one carb for each bank would have been much easier to tinker with. It would probably rob some power but it would much easier to work on.

-Jake

 

Today I finished getting all the boots and clamps.
I got very nice stainless clamps made in Germany from West Marine boat supply stores. The clamps are thin and have rolled edges. The clamp is not perforated, only formed, and the screw is stainless also. ($1.58)!

 

Here is a picture of the same set up BACKWARDS!! 2 cylinders- 4 carbs!

 

Start off with a set of clean, working stock carbs first......It would get your project going sooner and provide a baseline for improvements later.

stock carbs on a stock engine.......unless you're determined to improvise.

you could substitute for stock carbs but not improve in any way.

 

The carbs aren't that hard to remove for jet changes. It's not really that much more difficult than an inline four, and you do not have to remove all of those parts that you mention. Here is the correct procedure, it's a 5 min job after you get the hang of it:

Daugherty Motorsports - V4 Honda Carb Removal and Installation Procedure

 

I will think about it, if these give me too many problems. if it starts right up and idles then I can deal with midrange and full throttle after that.
When it first starts it runs for 1/4 throttle on the idle jet and the pilot air screw basically.

 

Today i received some valve covers I got from Ebay. Temporary ones until I get the ones I am getting polished. Now I can establish the engine position in the frame. I will just need to modify the rear cover breathe hose barb so I can remove the cover while the engine is in the frame. This is the thing I like about double loop cradle frame, you can see the entire engine and get to everything and work on it easily. The modern sport bike frame went the wrong direction. Frame all up high (raises the center of gravity), the engine is a stressed member and that can have consequences to the engine because engine cases can expand .004-.019 of an inch and with the frame wrapped all around the engine it is very difficult to work on. The only thing better is dropping the whole engine BUT getting it ready to remove is time consuming. Just do not see any advantages. And now the so called "NAKED" bike is getting popular again. Because you can work on it easier and the engine stays cooler etc.,. I think if this engine had a dry sump system the engine could have been 4 inches lower in the frame.

 

I have to think that with those long intake tubes, you will not have much of a bottom end. Plus the response most likely will be slow until you get in to higher 6k or above rpms. Hope you kept the stock setup. You may just need it later.

 

I make things happen.
Yes, I have the stock carbs if this plan does not work.
I learned that in the military....always have a 2nd way out.

 

Something I read recently....
"That depends on what your after? Long runner intakes are for the most part better used for low rpm operation, where as short runner intakes are better for high rpm operation. Thats really a super over simplication of the matter.

Intake runners are designed to take advantage of resonant tuning by using a series of pulses which occur in the manifold.
To get a rough idea of where the resonant tuning takes place determine the rpm at which the resonant tuning occurs using the approximations below. then compare them to the runner lengths.for example plug in 6000 rpm for each one

2nd Pulse Length: 108,000/rpm (18 inches)
3rd Pulse Length: 97,000/rpm (16 inches)
4th Pulse Length: 74,000/rpm (12 inches)
5th Pulse Length: 54,000/rpm ( 9 inches)"

 

This looks interesting and very useful.
Now I just have to figure intake areas.
Intake Runner and Peak Torque Calculator
Click on link above.

 

Using the formulas given in the link above this is what I get.

Each intake is about 6 inches to the CYLINDER head.
The area of all 4 intakes is 484 sq. inches.(121 each) 1.625 diameter tubing.
So the peak torque would be at about 2,799 rpm.
The optimum length of intake tract at 6,000 rpm would NEED to be, (including length from carb to intake valve seat -14 inches. and right now the length is about 13 inches total from carb to intake valve seat. Very close, and this puts all the torque at about 5,000 rpm. not bad.

 

Couple things:

Handling is somewhat more important than maintainence access on a sporting bike, therefore the frame wrapped around the engine. Kinda curious to see how yours will handle.

Cruising speed of the engine? I don`t know. Depends on what you mean by cruising speed. I just got back from a run on my R and anywhere from 5k-7k depending on traffic, with blasts up to the 11k redline, roadspeed around 80 is a good cruising speed for mine.

Looks like an interesting project. I am curious how the intake runners length will affect the fueling. I don`t really have any issues working with the 4 stock carbs, but it`s interesting to see your work. Not much of a chopper fan, but the powerplant you`ve chosen is one of my favorites, and I like well put together machines, no matter what they are.

 

Choppers are all about the looks, the vibe any sport bike will handle way better than a chopper. This frame has 42º rake so at low speeds the handling has to be with care. On the freeway it will just glide along and feel very secure. I used to race motorcycles but this motorcycle is just to putt around on and be relaxed.

 

OK!!!! The offset sprocket from Germany for my VF1000R just arrived and did not seem to get held up in customs. 7mm offset thats .270 thousandths or more than 1/4" but less than 3/8."
Now I can get those engine mounts welded into place.

 

Where did you ever here this? That's totally backwards from everything I've read and done and experienced. Short runners and or small cross section intakes have a higher velocity in the lower mid rpm ranges. Longer runners work better at higher rpms and can also create a ram effect in some instances. Depending on a lot of shit.

Resonance tuning is a bit more complicated than just using formulas for pipe. You also have wet flow, cross section, velocity, over lap and how straight it is to the valve. Just for starters. You have quite a turn in the intake there. Plus you will not be able to get 100% volumetric efficiency. Not many stock vehicles can come close let alone racing engines. NA of coarse. Pressurized is a totally different animal.

But you'll have a fun time sorting this stuff out. If you really want to get in to this stuff and learn from some of the best engine builders in the US and other parts of the world go here and poke around and ask questions. These guys do it for the love (hehe) and pain of it. This has got to be one of the greatest sites for actually straight info on the web.

Speed Talk

 

Thanks for the link to Speed talk.