Stock Carbs are GONE now.

Started by Single Carb Vision, November 03, 2013, 02:54:21 PM

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Single Carb Vision

Bike has been sitting in my unattached, unheated garage for over a month now. It was 31 degrees outside this morning so I thought this would be a good time to again test cold weather starting. Choke out, key on, one very shout rr and it came to life and continued to run. Cold weather starting is not going to be a problem with the new carb set up. That's all the news for now.

guzzi john

You have the solution on hand which I posted years ago. '83 carbs w '82 pilot jets and accelerator pump at max stroke. My '83 ran awesome w those mods. My AC Vision which runs great has very similar carbs-downdrafters unlike the larger Viragos w sidewinders that lots of guys put single carbs on. I also had an XV920R that ran good too-especially after I built a custom 2-1-2 exhaust for it(stock was worse than standard Vision system). Carb stuff is detail intensive-miss one little leak one obstruction and you're screwed. If I sound crabby EXCUSE ME!! I just plowed the 1st big snow from my drive after working on Daughter's Jeep-oil,coolant,block heater,serpentine belt. GJ ::)

Single Carb Vision

Like an old friend of mine would always ask while things weren't going so great,  "are we having fun yet?"

fret not

Soooo??  When do we get to see what you got?  You have piqued some interest among the 'crew', and now we want more information, pics, names, numbers, etc.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

fret not

Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Single Carb Vision

Finally took the bike out for a ride, it's been sitting for a long time while I was mounting a rack rear box and also putting on a small sissy bar/back rest for my daughter. I was on some country style back roads. The bike had no trouble hitting 85 MPH and I only brought it up to 8500 RPM (not both of those at the same time). About 6500 RPM at 85 MPH on the freeway heading back home in commute traffic. Refilled with gas at end of ride, millage was 40 MPG after an 80 mile ride. No hesitations no stumbles not one glitch of any kind.. It almost made me forget to act my age. I'm a happy camper with the single carb conversion.

fret not

So, after more than a year since your announcement we get what?  " . .but wait, there's more".  Are these guys going to offer carb 'kits' or not?  And if so, how much $ ?
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Single Carb Vision

I've asked them about kits a couple of times and they say they'll have to see what they can put together. It doesn't seem like they want to pursue that plan. I'll ask them about it one more time and if I get some news I'll let you know. Maybe the good news is just that we (I) now know it can be done for anyone that wants to work at it. Remember they had my bike for a long time before they were able to put together something that worked. I know there was a lot more to it than just getting a manifold, carb, air cleaner and throttle cable. If I get news, you'll get news.

Rikugun

It doesn't sound like Factory Pro will be making any kits. At the guestimated $1500 dollar price tag I doubt they'd sell enough to warrant the development time.

So what we know so far it's a Mikuni slide throttle of unknown size. Back in 2013 you referred to it as "Single downdraft slide carburetor". Is this accurate? All slide throttle carbs I've seen are side draft. A picture or two would go a long way to satisfying some of the group's curiosity. Without having to remove the fairing lowers or tank can't a pic be had that would show something?

Who were some of the guys you worked with at Factory Pro? Maybe a name and email addy would be useful for someone to make queries directly to them.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

fret not

Well, $1500. usd is a bit more than my "account" will allow, especially if there is a decrease in performance.  I can make my own manifold if necessary, especially since seeing those youtube "King of Random" videos.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Rikugun

Exactly. I agree the price is prohibitive although the performance loss doesn't appear to be as dramatic as I first thought. I thought if more specifics could be learned about the carb model & venturi size, jet sizes, etc. some may consider taking on the project themselves.

Obviously it takes some fabricating skills and cost but may be an attractive project for some. I'd think better overall fueling and significantly simpler carb design are worthwhile features although 40MPG seems a bit low for a Vision. In fairness the OP describes a riding style that may account for some of that.
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Blake

Have you done any tuning to the carb yet, or is it running as you bolted it on?  Reason I ask, if i have a couple 34mm round slide mikunis off a 600cc snowmobile, and i'm curious how "in the ballpark" it might be.  Made fairly simply adaptors to use the stock carb mounts.  For the price of a couple carbs and some throttle cable, if i can get the tune down "close enough" it'd be another easy conversion for others.  Once i swap the base cylinder gaskets on my motor, i'm hoping to attempt to start it up again.


Blake
"At first it's like a new pair of underware... Frustrating and constrictive.  But then, it kind of grows on you..."

Single Carb Vision

I have not touched it at all. The shop where I had the work done tried at least a couple of other carbs before the one on the bike now. They had to make modifications to the carb and they had their dyno to tweak the carb as needed to get the best results they could. I also don't have any idea what changes they may have made to the YICS. Hope your plan works out. If you have parts to experiment with you have nothing to lose but some time. I'm sure Ive seen some pictures or postings somewhere of other people switching to a one carb system. I was kind of surprised to see that after thirty years of problems more people haven't tried it. Good luck and if I do get more information to pass on to you, I will.

Rikugun

While the notion seems very simple in practice the swap is more complicated than it seems. Even the shop you tasked with the job seemed to be stumped for a while and this is their business. I'm not sure how much you have invested but I'd imagine it's more than some have paid for their Vision.

Without professional help and unless you get lucky, stumbling upon just the right carb setup on the first try seems unlikely. Without the use of a dyno and especially exhaust analyzer,  could result in many, many long hours of fruitless trial and error. That may be why more haven't tried it. Just my 2 cents.  ;)
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

The Prophet of Doom

Quote from: Rikugun on March 28, 2015, 08:24:44 PM
unless you get lucky, stumbling upon just the right carb setup on the first try seems unlikely.
A double word play.  Nice!!!

Seems to me if you have the gear and skills to make a different carb work, then you have the gear and skills to make the original carb work again.  Unless you particularly want to do a swap it seems all a bit pointless.




dingleberry

Stumbling... yeah was that intentional? I agree with POD on this one, summed it up well.
You like, oui?

Rikugun

Yes it was intentional but I felt a little bad for going for such low hanging fruit  :)

Also agree with the idea of skills utilized to get the OEM carbs right although some may just enjoy the project for it's own sake. Whatever gets your Vision functional and out on the road is good by me!
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

Single Carb Vision

  I agree with whatever it takes to get it running properly. It seems clear that these carburetors have been a problem for thirty years. There are parts on carburetors that wear out, ( I used to do all  of the work on my own cars and bikes when I was younger. I had many friends that were in to drag racing and NEVER did a rebuilt carburetor work as well as a new one ) there are shafts and pivot points that can't be replaced. Top that off with the fact that many of the replaceable parts for these Vision carburetors are no longer available. If you can find something NEW, that you can get to fit in the allowed area and only have to do some jetting  then that's a good reason to replace them because you will also be able to get new parts for a current model.

Add to the mix the YICS and the airbox, with it own air damper and your going to be fighting a never ending battle, as shown by thirty years of problems.

  About two years ago (while the work was being done on my bike ) I saw an 83 for sale on e bay. From all of the pictures it looked like brand new as it should have, it only had around 3,500 miles on it. I thought it might be a good idea for me to buy it because of the excellent condition. If I remember correctly the guy was asking $5,000.00 for it. High price but it was immaculate!

  Then there it was at the bottom of the add "just needs some minor carburetor work". That was all I needed to see to end my interest. It never got to the reserve has been met point and I didn't see it listed again.


Rikugun

I see your points and understand completely the route you chose.

Regarding used bike adds (Visions particularly) stating "just needs minor carb work" - add this statement to the list....  "the check is in the mail" and "I'll respect you in the morning".  ;D
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

The Prophet of Doom

Quote from: Rikugun on March 31, 2015, 10:38:10 AM
I see your points and understand completely the route you chose.

Regarding used bike adds (Visions particularly) stating "just needs minor carb work" - add this statement to the list....  "the check is in the mail" and "I'll respect you in the morning".  ;D
That's for sure.  Remember that black 400 I worked on last year?  That was sold as works well - just has a flat battery.  I put 2 months of labour into that and $1000 worth of parts and it was still giving problems.