2-to-1 carb

It's not the chore of syncing multiple carbs that makes this interesting (I keep 4 carbs on the 750 Seca in sync using my gauges and keeping just two in sync on the XS is a piece of cake). This sounds like a project that will let me play with my torch, welder and metal lathe. I just filled my O2 tank and I'm itching for something to practice my gas welding on.
 
It's not the chore of syncing multiple carbs that makes this interesting (I keep 4 carbs on the 750 Seca in sync using my gauges and keeping just two in sync on the XS is a piece of cake). This sounds like a project that will let me play with my torch, welder and metal lathe. I just filled my O2 tank and I'm itching for something to practice my gas welding on.
Well then get to work!! haha Just kidding. If you get around to trying the single carb mod out, please take some piccys!!! That would be great write-up material for others!!
 
Any two stroke carb that comes from around a 200cc engine should be fine. The two strokes need more CFM than the four strokes. Like mentioned before, I ran a 1991 CR250 two stroke carb on my old KZ440, and it ran like a dream. I would keep around a 34mm-35mm carb though.....definitely nothing bigger. I started with a 36mm Keihin the first time around on my KZ and it was way too big. I switched to the 34mm Keihin and never looked back.

The two stroke carbs of that size can be had on Ebay all the time for very decent prices. I'm not trying to sway anyone to do it, just something I plan on doing for myself and thought I would share the possibility with others here.

anytime I have the opprotunity to do something 2 stroke related to my bike...its well worth it...I even thought about sticking an old yz 490 motor in an XS 400 frame...what a ripper that would be in street trim!!!HEHEHHE!!!!!!:D
 
I built this last night after reading this post. I love the look of a single carb, but hopefully it'll work ok. I just used one of the stock carbs. I will probably build some flanges so I can bolt everything up but thought I'd try it like this for now.

A bit more welding and it should be ready to try.
 

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01ps, all i have to say is......I NEED TO LEARN HOW TO WELD! must be nice to just go 'hey i think ill fabricate this today' :) looks good man! i would love to do this simply for the 'huh?' factor...
 
I'm no engineer, so I'm looking for info from people who know. Is there any issue having the intake tracts different lengths with one cylinder much, much closer to the carb than the other?
 
I got the bike running today. It is a little slower to warm up, but once warm it idles well, is responsive, and I took it up to about 5000 rpm and it didn't break down or anything. I monitored the exhaust temps and they were even, and the plugs were matching and a nice brown, in fact, better than they have ever been (always a touch black and quick to foul plugs after idling for awhile). This would lead me to believe the different length intake runners are not affecting too much.

Of course, the proof is in the riding, and it is -30*C right now. Any "bench tests" I can do before I go much further (other than a smokey burnout)?

Here's a little video. I'll try and post a better one later, once I get it a little more polished.

 
Crap, you knocked that up in no time and it looks and works great :) All the info I've read says the different lengths of the intakes makes no difference. The example normally given is of a car inlet manifold. They have a single carb on most and all different lengths of intake depending on the snumber of cylinders, and they all work fine.

I don't know if this sounds strange but when I look at it I'm reminded of the alien busting out of John Hurt's chest. Maybe I need more sleep...
 
Any ideas on what to use for a flange to connect the carb to the pipe? I am using a piece of rad hose now, but I'd like something a bit cleaner looking.
 
tried to copy a pikky but they've disabled the right click on the site.

basically they are used in exhausts and look like a fatter version of our braided brake lines.
 
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