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Discussion Starter #1
I'm about ready in my xs650 project to think about carburetors. I've got the stock CV's for it, but i'm thinking i might go for something like this...
http://cgi.ebay.com/ebaymotors/Mikuni-34mm-Carburetor-for-yamaha-XS650-set-carb-XS-650_W0QQcmdZViewItemQQ_trkparmsZ72Q3a552Q7c39Q3a1Q7c65Q3a12QQ_trksidZp3286Q2ec0Q2em14QQhashZitem330244072708QQitemZ330244072708

has anyone here built a fairly stock xs650 with other then stock carbs? what did you use? any other thoughts on what i could run?
these dellorto's look retarded awesome...
http://www.mikesxs.net/mikesxs-fuel_system.php?category_id=4.9
 

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I think I'd toss some Mark II Amals on one

don't think it would need 36's at all

my guess is 32's would make it very crisp and responsive

avoid the phenolic plastic slides and be prepared to beef up the slide spring

oh, why Mark II's ?

they only weigh 1.5 pounds complete and flow very well

and who else has an XS with Amals?

VM mikunis by comparison are more than twice as heavy and the dellortos are in the same ballpark unless you score them in troublesome magnesium
 

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ebay
 

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those mukuni vm roundslides you picked out are awsome carbs. I can't say they are better than amals or not since I don't use amals, but for jap multicylinder bikes it is hard to beat a well tuned mukuni VM. Since xs650s are more like triumph 650s than cb650s I am curious how the amals would work.

hey hack, do the amals have an accelerator pump?
 

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Geeto, they do not have pumps and I'll answer your rhetorical question by flat out telling you the Amals are not nearly as refined as the Miks or Dellortos since they have much fewer selective tuning pieces and the jumps in between those available are much larger than the Dellortos and Miks.

So, this generally means that to tune them to acceptable levels of performance for road going bikes is easier but without modifying selective bits (with a drill or file) it generally is not possible to get as fine as results as possible with much patience and tinkering with off the shelf parts available for the other carbs.

But.... most tuners truly don't ever manage to get a high strung road going engine dialed in perfectly for any given day regardless of how refined a metering device they have hanging...... when is the last time you saw a guy with his log book at the track and all his meteorological equipment on hand?

Does this make sense?

However, if one is a tuner and isn't afraid to work over needles, slides, air bleeds, transition holes, etc...... most excellent results can be had that will rival anything out there and even for a perfectionist type tuner........ these same practices are needed even with the Mik's and Dellortos and are often much more cost/time effective than waiting to try out another bit on the way which may or may not be spot on just what the Dr Ordered.......

the caveat on the phenolic slides......... they suck as they are tremendously light and their surface does indeed seem to create a certain "stickion" to the slide bore

I never run them without a beefier slide spring and the available brass slides are better...... especially if you hard chrome them

The amals are very light, very simple, very compact, when used parallel the enricheners can all be easily linked, and flow very well per given bore area........

and they readily lend themselves to easy "owner hands on" tuning

as evidenced by my very rare and highly modified Mark 1 1/2 concentric (predecessor to the Mark II) fitted on my flatty forward facing with an open velocity stack

want a bag of worms? try tackling something like that, it's almost as much fun as doing blow thru pressurized carbs

I'm sure you've seen pix of it as well as my very long runner'd spread bore induction having forward facing tillotsons?

both work very well and my flatty will cruise 60 and under returning better than 80mpg, returns better than 70 @ 70, and has topped out at over 100 mph...... will cruise 80-85 all day long

up a long way from stock fuel mileage of 30-35 mpg and 60 mph is all she wrote

in any event, I have several many Mark II's

one other carb I'd be tempted to do on a XS would be.......

one of the twin throat CV Mic carbs having the 32 or 34mm bores

always thought a pair of them would be nifty on a CB750

they can also be sourced with smaller bores

I have a small collection of those types too...... they are kinda neat to look at
 

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Hey Hack any way you could post up some pictures of those twin throat CV Mic Carbs? I am kinda interested to seeing them.
 

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ok, on my list of stuff to drag out and shoot when the camera batteries are charged

should be soon
 

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I got used to the roundslide VMs because they are standard issue on kawi triples. I can cold strip and rebuild one now in approximatley 30 minutes. Super easy to tune and make really good power. On a kai triple I can make needle adjustments and jet changes without ever taking them off the bike. Suzuki GS carbs use VMs in a round slide bank setup with an accelerator pump and those flat rock too.

I have seen those dual throat cv carbs and have thought the same thing - now that I have the manifolds for a dual carb setup I might be tempted to....got any laying around?
 

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bigguns and lil ones











now this is one I wish I had the balls to put on several different bikes that I have laying about

you have to look carefully and give this one some thought











I meant to dig out the Fish carbs I have but was too lazy to go across the street and get them

those are frickin nuts

my apologies in advance to anyone offended by an old guy showing some old junk ;)
 

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ok the stunned silence is deafening

I ask you which way is up and just how scary is the thought of a sneeze back through the intake?

and Gee....... yes I have several laying about and I can see no reason for me to hoard them all other than I have a deranged and twisted carb fetish

I also have about 50 Mark II's from about 22mm on up to 40mm
 

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ok the stunned silence is deafening

I ask you which way is up and just how scary is the thought of a sneeze back through the intake?

and Gee....... yes I have several laying about and I can see no reason for me to hoard them all other than I have a deranged and twisted carb fetish

I also have about 50 Mark II's from about 22mm on up to 40mm
 

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FWIW: Sudco recommends the VM34 mikuni's, got a kit jetted and ready to go if you're bucks up.
Amals w/ velocity stacks would be the balls (but higher maintenance balls I'm guessing).
have fun with it. cheers, bcr
 

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Discussion Starter #15
hack, that last one looks stone simple. the only more simple fueling i can imagine is me squirting fuel thru the carb throat with a bottle while trying to change gears with the other hand. I fucking love it! what is it? where did it come from? and why does it look like a oddly shaped turd?
 

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simple but I"ll have to snap some more of it with all the internals taken apart, not quite as crude as it looks


the "cyclonic" air flow makes these very efficient at atomizing the fuel charge

came off a tractor and another interesting thing about is the inlet can be indexed variably nearly 360 degrees of the butterfly

just wherever you want it

did you figure out which way is up?
 
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