Different carb set up on VF1000R engine

[donald branscom]

I am building a bike using a VF1000R engine and I will be using these duel 36mm carbs from a Kawasaki 1500 early model.
Here is what I have so far. Just waiting for some special clamps and one boot.
The stock rubber boots were hard as a rock and had cracks in them. I am getting Turbo silicone high temp boots. Also in the next 3 days I am supposed to be getting the engine valve covers and side case covers back from being polished. Then I can finally get the engine bolted in place but I need those valve covers first to make sure of the clearances between frame and engine.

[matt1986vf500f]

that looks friggin awesome!! have you figured out what style frame you'll be building?

[JamieDaugherty]

Dual 36's isn't going to be able to feed that beast enough, are they? I'd think you'd need quite a bit bigger. The stock carbs are 36mm, and there are four of them!!!

[donald branscom]

Originally Posted by JamieDaugherty

Dual 36's isn't going to be able to feed that beast enough, are they? I'd think you'd need quite a bit bigger. The stock carbs are 36mm, and there are four of them!!!

These carbs can feed a 1500cc V twin. They did actually.
This engine is only 1000cc.
One carb feeds One cylinder at a time.
There are lots of varibles but I will get into tuning, them at the finish.
The formula is engine volume X ENGINE RPM devided by.3456= CFM or venturi size. With one carb you could have about 13,000 combinations of jetting possible.

The VF1000R is like two v twins side by side.
The firing order is 1-3-4-2 so The first piston fires(1) left carb, then piston 3 fires(right carb) and so on.

[JamieDaugherty]

Originally Posted by donald branscom

These carbs can feed a 1500cc V twin. They did actually.
One carb feeds One cylinder at a time.
There are lots of varibles but I will get into tuning, them at the finish.
The formula is engine volume X ENGINE RPM devided by.3456= CFM or venturi size. With one carb you could have about 13,000 combinations of jetting possible.

Apples and oranges, bro! That 1500 is a super low revving engine, so they can get away with it.

It tired to beat around the bush, but let me be blunt - those carbs are WAY too small for that engine. You will have serious issues trying it that way. It will probably be smooth as silk down low, but after about 6-7000rpm (just a guess) it will fall on it's face.

[donald branscom]

Originally Posted by JamieDaugherty

Apples and oranges, bro! That 1500 is a super low revving engine, so they can get away with it.

It tired to beat around the bush, but let me be blunt - those carbs are WAY too small for that engine. You will have serious issues trying it that way. It will probably be smooth as silk down low, but after about 6-7000rpm (just a guess) it will fall on it's face.

Yes the 1500 v twin revs are lower but the mainjets in the carbs are 118's. I will increase those if necessary. I will just have to try and see what I get.
If I need to, I WILL put a 4 barrel carb on it. HHAHahhhahaa

[NorcalBoy]

I will be interested to see the outcome of this setup. At upper rpm's, I have more thoughts than just the venturi size of the carbs. I do wish you luck, and hope it works out for you in the end.

[mrich12000]

Holley sounds nice make the intake runners up from sheet aluminum and try it . I really like to see that one!!

[donald branscom]

Originally Posted by mrich12000

Holley sounds nice make the intake runners up from sheet aluminum and try it . I really like to see that one!!

I do not know how those Holly carbs work but i do know there is a LOT to know about them. People spend many years learning the tricks on those.

[donald branscom]

I understand the concerns about using these carbs but think about this...
If the stock engine used a 36mm for each cylinder, and each cylinder only fired ONCE each 360º.
The 1500cc engine(the donor carb engine) fires once every 180º and you only have ONE carb feeding that cylinder too.

Sorry for the poorly written original.
I edited it to make it make more sense.

[donald branscom]

The Saab V4 engines were 103 cubic inches and ran on one 34mm carb.
The Honda VF1000R is 61 cubic inches and should run well on two 36mm carbs.

[mrich12000]

Still, I'd like to see the Holley on her..

[donald branscom]

Originally Posted by mrich12000

Still, I'd like to see the Holley on her..

The Holly is made for a 350 cubic inch engine and the VF1000 is only 61 cubic inches. But it would look good though.

[relic rider]

Think of it this way, total cubic feet of air that will be going through the carbs ,I bet the # are higher on the vfr at red line than the v twin .Just a thought.

[donald branscom]

Originally Posted by relic rider

Think of it this way, total cubic feet of air that will be going through the carbs ,I bet the # are higher on the vfr at red line than the v twin .Just a thought.

It is the VF1000R not the VFR.
I will check that out too .Thanks.
The Formula: VF1000R- 61 cubic inches X 6000 RPM=366000 devided by 3456=105 cubic feet of air.

The Kawaski 1500 V twin-91.5 X 6000 RPM=549000 devided by 3456=158.cubic feet of air.

Holly carb is about 650 cubic ft. of air !!!

But what is the CRUISING rpm of the VF1000R?

[relic rider]

sorry was referring to vf1000r motor not to be confused with vf1000f or vfr

[vfrcapn]

Originally Posted by donald branscom

It is the VF1000R not the VFR.
I will check that out too .Thanks.
The Formula: VF1000R- 61 cubic inches X 6000 RPM=366000 devided by 3456=105 cubic feet of air.

The Kawaski 1500 V twin-91.5 X 6000 RPM=549000 devided by 3456=158.cubic feet of air.

Holly carb is about 650 cubic ft. of air !!!

But what is the CRUISING rpm of the VF1000R?

Well, my 1000R project is still sitting in the garage but I'd say cruising is about 5K rpm, if it's similar to my VFR800. Redline on the 1000R is about 11K rpm, (same as the VFR basically) so you might want to factor that in to the calculation. Isn't redline on the 1500 around 6K?

[JamieDaugherty]

Originally Posted by donald branscom

The Saab V4 engines were 103 cubic inches and ran on one 34mm carb.
The Honda VF1000R is 61 cubic inches and should run well on two 36mm carbs.

I'm just trying to help because I'm sure that you will have problems. One thing that I've learned over the years of product development is this: if it's the right answer, you'll eventually get there yourself. My intent was to help save you the trial and error pain.

Make sure to keep us up to date on the progress. I love projects like this!

[donald branscom]

Originally Posted by vfrcapn

Well, my 1000R project is still sitting in the garage but I'd say cruising is about 5K rpm, if it's similar to my VFR800. Redline on the 1000R is about 11K rpm, (same as the VFR basically) so you might want to factor that in to the calculation. Isn't redline on the 1500 around 6K?

Thanks VFRCAPN. That is useful information.
I did not know redline was so high on the VF1000R engine.

[donald branscom]

OK...OK... You got me worried so I did the math.

Here is what I come up with.

The VF1000R if run up to 10,000 rpm.
61cu, ft. X 10,000rpm=610000.devided by 3456=176 cu ft of air needed.

BTW 3456 is 1728 X 2 since it is a 4 stroke.

The Kawasaki donor engine CARBS if run up to 6,000 rpm.
91.5 cubic ft. X 6,000rpm=549000 devided by 3456=158 cu, ft. of air needed.

So 158cu ft. compared to 176cu.ft. but I will not be running the VF1000R at 10,000 rpm much because I will not be racing. Should work.

[crustyrider]

Originally Posted by donald branscom

OK...OK... You got me worried so I did the math.

Here is what I come up with.

The VF1000R if run up to 10,000 rpm.
61cu, ft. X 10,000rpm=610000.devided by 3456=176 cu ft of air needed.

BTW 3456 is 1728 X 2 since it is a 4 stroke.

The Kawasaki donor engine CARBS if run up to 6,000 rpm.
91.5 cubic ft. X 6,000rpm=549000 devided by 3456=158 cu, ft. of air needed.

So 158cu ft. compared to 176cu.ft. but I will not be running the VF1000R at 10,000 rpm much because I will not be racing. Should work.

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.......

[JamieDaugherty]

Originally Posted by donald branscom

OK...OK... You got me worried so I did the math.

Here is what I come up with.

The VF1000R if run up to 10,000 rpm.
61cu, ft. X 10,000rpm=610000.devided by 3456=176 cu ft of air needed.

BTW 3456 is 1728 X 2 since it is a 4 stroke.

The Kawasaki donor engine CARBS if run up to 6,000 rpm.
91.5 cubic ft. X 6,000rpm=549000 devided by 3456=158 cu, ft. of air needed.

So 158cu ft. compared to 176cu.ft. but I will not be running the VF1000R at 10,000 rpm much because I will not be racing. Should work.

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?

[donald branscom]

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.

[Jakobi]

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

[donald branscom]

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)!

[donald branscom]

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

[squirrelman]

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.

[JamieDaugherty]

Originally Posted by donald branscom

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.

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

[donald branscom]

Originally Posted by squirrelman

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.

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.

[donald branscom]

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.