Kawasaki VN750 Forum banner

1 - 20 of 21 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter #1
So, I am a mechanical designer and a 3d printing nerd. I'm seriously considering designing a single carb intake manifold that would be "drop in" for this bike and having it 3d printed in glass reinforced nylon. Coming from Shapeways, it should be relatively cheap, and I can print prototypes at home for testing. Anyone have a "dream carb" they wish they could bolt up to this bike? I've seen people talking about the mikuni VM38 a bunch, any other suggestions? This project will likely be a ways down the road, but you gotta start somewhere. I'm going to try to get a good 3d scan of the existing carbs to get my angles nailed down, but after that real development will come quick.
 

·
Registered
Joined
·
7,924 Posts
The Mikuni VM38-9 may be a good choice, seems readily available with soild aftermarket and racing support .

The VM looks to have a generous sized drain cap and accessible fuel bowl.

Striking a balance between the carb/air filter sticking out too far, and ready access to the choke lever, might be a challenge.

The carb/air filter protruding too far to one side is something that often makes a single carb conversion look a bit freakish.

Are there any, readily available/serviceable downdraft carbs? Would that layout be better or worse for this mod? A Motorcraft vacuum secondary 2bbl comes to mind, was used to convert some Goldwings for a while.

But think about the last time you saw a Ford Pinto.
 

·
Registered
Joined
·
7,924 Posts
This article discusses another question I had.

http://www.vintagebikebuilder.com/choosing-aftermarket-carbs.html

The VM 38-9 doesn't appear to have a vacuum port, so a nipple would need to be in the manifold, or a petcock swap will be mandatory.

Also a link to Niche Cycle there that has some parts VN owners might need.
 

·
Registered
Joined
·
18 Posts
I actually made my own single carb conversion im in the process of tuning actually. I bought some 1.25 od pipe from the hardware store, and a 40mm harley knockoff carb and am running it. The couplers are just 1 7/16 fuel hose from napa. The carb to intake manifold boot is the stock engine to carb boot just because of the angle it gives. My air cleaner setup could be a harley setup but I'm cheap and the bike had k&n filters in the stock cleaner "ears". I took some 1/8 stainless sheet and made a backimg plate same profile as the air cleaner. The air cleaner is attached with 5/16 stainless carrige bolts. With the setup it clears my legs with the forward controls. I am prolly going to extend my rear brake lever for comfort but not needed. I can try to get some pics and post them here is y'all want or I may just start my own thread lol. I'm still working on the tuning but I think itll be so,much better than the stock carbs.

As for choke I just used a harley choke cable and put a bracket on the frame under the tank on the left side with a hole for the choke.
 

·
Registered
Joined
·
7,924 Posts
We love pics here, post them somewhere when you can.

:worthless

Hope this isn't a double post, first one wasn't showing.:grin2:


I actually made my own single carb conversion im in the process of tuning actually. I bought some 1.25 od pipe from the hardware store, and a 40mm harley knockoff carb and am running it. The couplers are just 1 7/16 fuel hose from napa. The carb to intake manifold boot is the stock engine to carb boot just because of the angle it gives. My air cleaner setup could be a harley setup but I'm cheap and the bike had k&n filters in the stock cleaner "ears". I took some 1/8 stainless sheet and made a backimg plate same profile as the air cleaner. The air cleaner is attached with 5/16 stainless carrige bolts. With the setup it clears my legs with the forward controls. I am prolly going to extend my rear brake lever for comfort but not needed. I can try to get some pics and post them here is y'all want or I may just start my own thread lol. I'm still working on the tuning but I think itll be so,much better than the stock carbs.

As for choke I just used a harley choke cable and put a bracket on the frame under the tank on the left side with a hole for the choke.
 

·
Registered
Joined
·
18 Posts
So heres what i got, ive got some tuning to do like i said before, the throttle cables im using the stickers and trimming them to fit. Some new barrel ends for the cables are on order, once tuning is com0lete im pulling it all apart again and painting my engine again, (fuel leaks take off paint real well), getting some black hose clamps, and putting it all back together. With the angle from the stock boot it clears my legs with the forward controls, and from where i belive the stock pegs went. A thinner air cleaner could be used but i had this k&n plus one more for a spare. With this setup the idle is about the same, i can already tell it uses more fuel, but starts so much easier, and throttle responce is right there. So far it runs better than the stock carbs even after the ear shave. Still need chome cable mounted, as well as removing the stock one.
 

Attachments

·
Registered
Joined
·
7,924 Posts
Looks alright, choke is perfect.

Always said the single carb should make it easy to drop the bowl.

Interested in seeing your manifold, and maybe one shot of the bike from farther back.

It works, and that's a success.
 

·
Registered
Joined
·
18 Posts
Yea tricky with the pics lol. My front camera is shot so gotta take em with the reverse camera so i kinda got no eyes lol. I'll get some when i get the manifold off. Going to smoothe up some welds and whatnot then coat everything nice and pretty. I'm so fed up with the stock carbs that in doing a jig im so happy lol. Im actually on my second set of carbs before they took a crap. The center section that joins the carbs broke twice. If this didnt work I was going to try to machine a billit aluminum section.
 

·
Registered
Joined
·
12 Posts
I recently had a thought and, I hope you understand what im after.

Turn signal bases for OEM turn signals. Im not skilled enough to make it happen via CAD but, Id be interested in a set if you feel froggy.

I dont know how to tag someone or, if they would get notification of a mention. Zakm0n ........
 

·
Registered
Joined
·
7 Posts
Hi i´m brasilian
i have one vn750 1994 with 22k miles
my dream carb is a quicksilver edelbrock 38mm and recently bought in ebay
i already tested with one koso 38mm one honda twister carb(250cc) and with honda falcon carb (400cc) and with both the bike has started.
any pictures in facebook group vulcan 750 riders

the carb is still coming to Brazil. When possible i ll send photos
tks
Evandro Miranda
 

·
Registered
Joined
·
118 Posts
Hi i´m brasilian
i have one vn750 1994 with 22k miles
my dream carb is a quicksilver edelbrock 38mm and recently bought in ebay
i already tested with one koso 38mm one honda twister carb(250cc) and with honda falcon carb (400cc) and with both the bike has started.
any pictures in facebook group vulcan 750 riders

the carb is still coming to Brazil. When possible i ll send photos
tks
Evandro Miranda
Have you a manifold made for the conversion? Post some pics if you have. Oh and welcome to the madness 😁
 

·
Registered
Joined
·
118 Posts

·
Registered
Joined
·
118 Posts
Ok cool. Let us know when you get it going. A video of it running would also be appreciated. Nice job so far tho. Takes a lot to actually dive in a make it.
 
1 - 20 of 21 Posts
Top