How do you run this engine setup and is for looks or actually work !!

[Rusty_S85]

This is how bike builder did his!

Looking at this pic I cant help but think in my head that there is a simpler more compact way of doing it to have one carb set up to come in around half throttle.

But at last I don't think I will exert a bunch of time on it even though it would look cool. Biggest draw back is engine I am looking at has 40mm intake and the dual carb intake is only available in 30mm. If I were to make my own custom intake I would probably down size from Mikuni VM18mm carbs down two to four mm sizes to off set the dual carb setup and just have both linked together.

 

[gary55]

Yes that's a problem because 28mm of carb combined on a stock or even mildly done engine will not yeild any gain in fact it will create a bog more than the stock single does opening to quickly!

Gota make sure yer engine has enough suck power. Else wise ya give er to much and she'll just choke on it.

 

[Rusty_S85]

Gota make sure yer engine has enough suck power. Else wise ya give er to much and she'll just choke on it.

Yep and you can usually tell if you have too much fuel or not enough. If you cover the mouth of the carb and reduce the air and enrichen the fuel mixture artificially and engine runs better then its lean. If its no change or runs worse then its probably rich. verify by inducing a vacuum leak after the carb to provide more air to the engine and if runs great it will be rich.

In any case I am hating myself because I'm over on Zeda`s site and I am thinking about going with a Zeda 80 sleeved cylinder as a non chromed steel cylinder would take more abuse than the Chinese chrome. I also am contemplating a reed valve as Ive been reading they are great at lower rpm for making power.

 

[Frankenstein]

 

[Rusty_S85]

View attachment 78441

Yep something like that or just a simple bell crank drill a hole on the outside edge and drill a hole on the inside edge. One hole will pull more than the other. For example if you pull the arm via throttle cable the cable on the outside edge will pull more cable at a faster rate than the cable on the inside closest to the pivot. That cable will pull less cable at the same rate of the outside mounted cable. This in effect would double it so when you are at 1/2 throttle on your primary carb your secondary carb would be at 1/4 throttle. Problem how ever with this set up is you will never get both carbs to be at 100% throttle unless you incorporate a spring to allow the outter most cable to over cam when it hits wide open throttle allowing the bellcrank to keep turning to pull the secondary carb cable to 100% throttle.

Or use something like a park brake cable equalizer. Two ball end cables are hooked to a plate that has a triangle hooked to a single cable. Which you can design in such a way to lock it in position via spring tension where primary carb is pulled at 2 times the rate of the secondary so your secondary will start to open up around 1/4 throttle and you can fine tune it up to 1/2 throttle even. The spring loaded design would allow the triangle equalizer to over cam when one cable hits its travel extent and the other cable would keep pulling. Down side with this setup is it will require more room as well as a mounting bracket to make it function properly.

Best way is to just simply link both cables together and size the two carbs properly so two smaller carbs would provide the flow as if you were running one larger carb. This way both carbs operate at a 1:1 ratio between each other.

 

[Diamond Back]

Well, if it's for show I'd keep the duel plugs and drop the duel intake, the head looks cool with a double plug and since it's show you can cap and wire one plug with a false end (or just hook it to a CDI that isn't hooked up to anything) and the other plug make as the actual ignition source.

Pick up some Fanta orange brake caliper paint (or whatever paint won't melt from heat and chemicals) and paint it up a bit. Definitely get a barrel type rear mount gas tank, the stock one would kill the look. Maybe get a leather saddle bag to spice it up a bit (plus it's cooler than a white plastic bag dangling off the handlebars.

I was actually thinking of getting a round long leather Harley Type Saddle Bag to mount behind the seat and modifying a barrel type Gas tank to HIDE in side it..That be cool you would never see it...I think if i were to get a rear barrel type gas tank i would most definetly have to cut and re-weld the mounting bar cause of the angle of the chopper seat post is at lower angle and the tank would be hitting the tire...it would take some modification to get it to sit right,,,Thats why i think about turning a behind the seat short sissy bar saddle bag into a hidden tank....WHAT YOU THINK ???

 

[Diamond Back]

I was actually thinking of getting a round long leather Harley Type Saddle Bag to mount behind the seat and modifying a barrel type Gas tank to HIDE in side it..That be cool you would never see it...I think if i were to get a rear barrel type gas tank i would most definetly have to cut and re-weld the mounting bar cause of the angle of the chopper seat post is at lower angle and the tank would be hitting the tire...it would take some modification to get it to sit right,,,Thats why i think about turning a behind the seat short sissy bar saddle bag into a hidden tank....WHAT YOU THINK ???View attachment 78455 View attachment 78456

The Dual throttle is easy,,,,you guys ever see a YAMAHA BANSHEE ATV... Basically the primary cable goes to carb #1 and then you run a cable coming out Carb #2 and crimp it to Cable #1 about 4 "inches up . Then have that cable assymbally run thru a mounted twice as large 6"inch teflon tube... Now when you twist the throttle the two cables at the Y intersection will run up thru the large,wide teflon tune that mounted in one unmovable spot underneath the top cross down tube,, and then i would try two 2 NT carbs and of course use the top needle clip position on both CARBs and would solder both main jets and just start with the smallest micro drill size and keep moving up till we get it to run and just mess with needle clip positions and maybe some choke lever action or drill holes in the choke lever slide to try to gat the air fuel ratio to as close to 14 to 1......as best i can.....or maybe use two 8mm WALBRO CARBs of some 32cc weed wackers...that might not work to well seeing those CARBS are Diaphram fuel pump and require a pulse signal from crancase....It will Be a trial and error MODIFICATION EVENT ,,,but anything is possible if you put your mind to it with the help and input of your fellow GAS Bike Friends on here,,,ya know I think I wight just try it,,,,,first thing is first,, finish building and breaking in the chopper motor in stock form,, and also finish the 3 bike builds I got going on for three 3 different customers....uugggggghhhh its some good easy side money to help by the dual setup parts I need...and I wont be spending $100 on CR Machine dual ignition...I am sure Mike ((JAG)) could tell me how to wire up to stock set ups or i could just get another super charged CDI for $19.99.......

 

[Frankenstein]

If you're going to hide it then don't even mess with the metal tank, Pvc is apparently a completely viable option that is rather gas resistant, and if you buy a tank sealing kit you can coat the inside of the Pvc tank for an extra layer of protection. Probably the easiest to really custom fit a tank in a leather bag.

 

[gary55]

I was actually thinking of getting a round long leather Harley Type Saddle Bag to mount behind the seat and modifying a barrel type Gas tank to HIDE in side it..That be cool you would never see it...I think if i were to get a rear barrel type gas tank i would most definetly have to cut and re-weld the mounting bar cause of the angle of the chopper seat post is at lower angle and the tank would be hitting the tire...it would take some modification to get it to sit right,,,Thats why i think about turning a behind the seat short sissy bar saddle bag into a hidden tank....WHAT YOU THINK ???View attachment 78455 View attachment 78456

That would look good. I was thinking about a post mount on this one. Covering it with a bag is a cool idea.View media item 60658View media item 60657

 

[Diamond Back]

That would look good. I was thinking about a post mount on this one. Covering it with a bag is a cool idea.View media item 60658View media item 60657

Gary thats a cool bike,,,,is that the new model thats out there.. I have it saved somewhere of this new bike that justcame out and it has a full copper frame and wide 20" x 3" tires front and back...If I can Find It I will post it..
Can you guys help me with were to get a saddle bag to do this hidden tank in,, and I could use a hand at how to build a gas tank to go inside,,,,please try to keep price to a minimum cause I dont make much if anything at all....and these bike builds I am doing at a low cost for the people and the bikes are starting to nickel and dime me to death,,,I got to make custom motor cuz the new Mongoose Bike has a 3" foward down tube and the frame is extra compact..