V65 on 1200 plenum

[ekvh]

My next project is supposed to be a Weber, but looking through my junk piles I started looking at the Magna V65 carbs I have and comparing them to my 1200 carbs. Very similar and I think quite simple. The v65 are 36 mm with an exit the same size (or close to the same) as a 1000. The 1000 elbows fit on. I am happy with the 77 carbs on my hybrid after MUCH jetting chasing, butI still wonder if we can't squeeze more out so I looked at the carbs. They looked so much alike, I wondered if they'd bolt up. They don't. But with a drill bit and my two-hand-Yankee-drill press I slotted the holes and they will bolt up and line up with the openings quite well. Next was linkages. They are waaaay different, but throttle shaft holes are the same spacing for the butterflies so I swapped the shafts over. Some had to be cut a little, and some plugs had to removed and replaced. They just tap in and out. It required some hand work to open the slots for the butterflies to fit the throttle shafts, but they are in there and open and close nicely. I had to swap choke linkages and will have to make my own fuel tubes. The v65 is larger diameter fuel lines and of course, different lengths.

I need to clean the carbs up, make the fuel tubes and then adapt the 1000 runners. The 1200 has the carbs canted about 40-45 degrees, so I plan to slice some 1000 elbows at the appropriate spot and then join them with fuel rated hose. I'm not positive it's going to fit in and out yet, the stock 1200's were really tight for the 1000 frame. The other problem with 1200 elbows was that they don't line up properly for the 1000 heads. They have to be twisted a bit and it leaves a lip on the head side to impede flow, it's almost a quarter inch. This way should line up nicely and give a boost at the upper ranges. I hope it's not too much air at idle. There are oodles of jets available as well as needles which can be adjusted.

I'll post some pics if interested, or maybe wait and see if it's a bust or not.

 

[dan filipi]

Nice project!

Post pics whether a bust or not please.

 

[AApple]

opcorn: :builder: opcorn:

 

[ekvh]

as you can see, they look just like 1200 carbs, just 4mm larger inlets and outlets. Should flow a lot more air.

I have a question before I start wrecking more parts. In the last photo, there is a little nipple hanging down for draining the float bowls. It is pointing up in the pic, but the question: Can I hack them off? They are the part that makes it tough going in and out and clearing the water pipes. I think I can. Well I know I can, but will they leak?

Those funny things sticking up in the back are 1000 carb holders to keep them lined up and not lose my sync springs.

 

[dan filipi]

If they serve no purpose other than draining the float bowls, off with them I say.

 

[zman]

They stick out so that one can put a hose on them is they like, hacked down they will still drain and function, least that my opinion, I would saw off in increments just to be sure I am not going into a chamber or better remove one of the screws and look down in.

 

[ekvh]

I may try and find an old sacrificial body somewhere. Any one have a junked body laying around?

 

[zman]

I think your good to cut flush if you need to, run a tiny wire through with the screw out and some good light, if the hole is the same size all the way up then your OK to cut.
Just looking at the screw will tell you how it seals, show a pic of it if you can.

 

[Ansimp]

The seating of the drain screw should be in the float bowl and as stated they are to allow you to slide on drain hoses, or in my case clear tubes to observe the actual height of fuel in the bowls when setting up the carbies.

 

[ekvh]

They are done. I noticed that on two of the 1200 bowls they were very short. So they're gone. Cleaned the bottom jets. Most were plugged solid. Starter jets all had to be drilled. I wonder why they pressed that one in? Anyone know what Honda recommends when they are plugged?

I'll go through the tops tomorrow, try and pick my best diaphragms and see what needles I'll need. The V4's used different springs, needles and main jets because two carbs were straight down, and two were vertical, somewhat. I will probably have to take a guess and order the two more needles and springs unless my 1200 ones will work,so they all match. I drilled all the main jets to 123, they were 120 and 116. In hindsight, I probably should have soldered the 120's and drilled them to 116. Idle jet was 38 on the v65, 40 on the 1200. I kept the 38 to start. I'm feeding 100 more cc's but four less valves. Early cams.

I thought this was a way off in the future project, but it's not looking too far away from trying.

 

[slabghost]

Interesting build. Still the cv carbs but they do well enough it seems most manufacturers have chosen them. I like stealth mods. They improve performance yet look stock.

 

[ekvh]

Stealth mods. I'm thinking of finding some BMW signs to stick on my valve covers. Nobody knows what my bike is. I tell some guys it's a Porshe. They kind of nod and look puzzled.

 

[slabghost]

Tell them it's a race motor from a 67 Yugo! :smilie_happy:

 

[ekvh]

Got to put a little more time in on this mod. It seems very doable ---even for me! I had to jbweld the slotted holes in the plenum and drill them again. They appear to be sealed well. I had to shave quite a bit off the throttle stop in order to get a decent bench sync. I think it was the rubber spacers which are like o-rings between the carbs and plenum. They are thicker and hold the carbs out a strong 1/8" each side. That moves the throttle shafts further away than the stock 1200's. I'm glad I spotted that now. If you look at the pic below you can see the black line holding it out. I'll try and get a pic of it later.

Today's task was to chop some 1000 intakes at 30 degrees to match the canted version of the 1200 plenum. The v65 carb bowls are designed for this and sit quite level.

First I set a rack of carbs on some plywood to make a jig. Then I guesstimated the width needed to cut. I was pretty nervous about using my radial arm saw, but that's what I did and it was a piece of cake!

I had a fire extinguisher handy as I was cutting metal with a fair amount of sawdust. Clean all you want,mothers going to be some and it is easily combustible. You can see I just put the jig with the elbows up adjusted to where I thought it had to be and slowly walked the carbide blade through.

Here's a look at the fit. I took a bit more off since this pic and I'm currently heating some inch and a half fuel rated hose to squeeeeeze over the elbows. Couldn't quite do it cold.

I'm hoping this will feed my hybridized 1200 better. More flow at upper rpm, but hopefully still have mild manners at idle. They fed 1100's with 4 valves per cylinder. Time will tell.

 

[slabghost]

Is this a project because you had the carbs on hand or an attempt at stock look improvement?

 

[ekvh]

I had them on hand, and to see if it is an improvement. Anyways back to the drawing board. It's too tall to fit under the frame, by a good inch.

Notice the height of the 1200 intake manifold sitting next to it. Stymied right now. Maybe Mikuni flanges and cut the bases off mine, and longer hoses.

 

[zman]

so your saying you ran out of top space, what about underneath? Can you lower anymore?

 

[ekvh]

There's room underneath, if I keep cutting the elbows where I have been cutting, it will impede flow, I think...?? Maybe not. I guess I've wrecked those elbows already. I was kinda proud of how nice they fit. I guess I could go hack another inch off and see how it lines up. I will need new fuel hose. I may try and find some 1-5/8" as it is tough stretching it over the elbows.

 

[zman]

What about using 4 1200 manifolds?

 

[ekvh]

The 1200 manifolds are tiny compared to the v65 and 1000's. They measure about 1.2" at the head while the 1000 head and v65's are about 1.5". Stock 1200's ran decent on these despite the intakes not really lining up cleanly with the 1000 heads. Anyways, zman, after your comments I went and lopped about 3/4" off each side and that dropped the whole rack over an inch. It should go in now, but now I have to find rubber boots to work. I have to have 1-5/8" id for the v65 exits. The way these are cut at an angle, I now have 1-3/4" across the cuts side-to-side, and 1-7/8" top to bottom. The 1-1/2" fuel line was not pliable enough to stretch it. I may have to try radiator hose or something more stretchable.

The cutoff valve mounted under the carb plenum looks to be kind of tight for the thermostat and top motor plumbing. I'll try and find something tomorrow.