FZR carb conversion

Started by Walt_M., May 18, 2016, 06:09:43 AM

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Walt_M.

You already have what the carb to manifold adapter looks like. Make it look like your stock carb spigot and about 50 to 60 mm long. You can't use Vmax carbs straight to the manifold because there isn't enough room in the V.
Whale oil beef hooked!

artbone

Quote from: Walt_M. on July 03, 2017, 06:51:09 PM
You already have what the carb to manifold adapter looks like. Make it look like your stock carb spigot and about 50 to 60 mm long. You can't use Vmax carbs straight to the manifold because there isn't enough room in the V.

That's what I thought. You guys have made this so much easier though how much easier is still to be seen. Thanks for your good work.
Art Bone

'83 Yamaha Vision in the Classic Black and Gold  Running
'82 Yamaha Vision Running
'74 Norton Fastback - Colorado Norton Works #26  Running
'73 Norton Interstate  Running
'75 Triumph T 160  Running
'62 Harley Davidson Vintage Racer
'61 Sears Puch  Running
'15 Triumph Scrambler
'17 Honda Africa Twin
94 Kawasaki KLR 650

Ron_McCoy

Just a follow up on this project. I have just over five thousand miles on it since the installation. It starts easily and quickly. Now that winter type weather has arrived, it likes a little warm up before it will accept much throttle so the jetting is pretty close. Getting 50 - 55 mpg with really good throttle response, no stumble or hesitation. Yamaha should have built them this way to begin with. It's a much more enjoyable motorcycle.

jefferson

The vmax carbs do fit right up to the manifolds according to my friend that has done it. They just need to be spread apart more in order to line up. He has that setup on the bike now. The accelerator pump nozzle fell out of one of the stock carbs and went through to the combustion chamber. He got some of the timing off somewhere during the teardown and reassembly and it looks like he may have bent some valves. It was kind of surprising, but there was no visible marks from the nozzle rattling around in there. Sure flattened it out though.

Walt_M.

I went back to the beginning of this thread and will modify my statement that vmax carbs will not fit straight to the manifold and be linked together.
Whale oil beef hooked!

auto

Anyone have two vmax carbs they want to sell.Like to try a conversion but don't want to buy four carbs.Also looking for a trashed out exhaust that I can open up to explore best way to improve flow,but not too loud.

Walt_M.

People are pretty brave on pricing Vmax carbs while I have found FZR600 carbs around $100-125. And, as I found out, the first and third carbs were best for my purposes. Another benefit of this conversion, since I no longer have the airbox flapper, I have hardly any oil in the airbox from the crankcase vent, which makes perfect sense when you think about it
Whale oil beef hooked!

fret not

While looking through the various offerings of carburetors on eBay I have found terminology is often misused.  The term "carbs" or carburetors is all too often used when trying to sell throttle bodies for fuel injection.  You have to look closely at the photos, and if things aren't clear then ask a question of the seller to establish clarity. 

A couple years ago I bought a set of throttle bodies from a Suzuki SV650, thinking I would graft them onto my Vision.  After some serious brain sweat I came to the conclusion that grafting carburetors on to the Vision would be a smaller mountain to climb.  In the process I got an introduction to fuel injection, and the difference between the fuel systems.  FI requires rather high fuel pressure, about 42psi as a minimum, and consequently all the fuel line fittings are designed to deal with such pressure.  FI may look simpler at first glance but in reality carbs are easier.

Throttle bodies seem to be much less expensive than carbs.  My guess is they seldom need work or replacement so not much market for them.  Carbs on the other hand seem to sell more easily and so maintain their market value.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Kenny

    All right ...
    I'm into the conversion mode - I've got a set off of a 93 on the way ! I must say I'm a bit ticked with the 83 carbs I've reworked over and over , I can get them to work o.k. but after a year or so I need to do them again . Earlier in the scheme of things I sent a set of 83 Canadian Carbs to Martin at S.C.I. and he sent them over to Japan & they made a carb kit up for the 83 as the only one they had was for the 82. After that I overhauled all the carbs I had -did them up in an Ultra-Sonic Cleaner at work until they pretty much Glowed in the dark ! But after a couple of years of use , (even with an inline filter installed) I was back to reworking them again. Geez I hope I'm not repeating myself here..
   Can't wait to get started , I'm calling this a Christmas Gift.
                            Cheers Kenny         
2 XV 920rh 81
1 Red/White 83
1 Blue/White 83
Bmw R100rs 84
TDM 850  92

fret not

Well, good luck with the process.  You just have to keep in mind that there is less troublesome performance at the end of the journey.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Rikugun

I can tell this is a sore subject to ask about and I'm not trying to talk you out of the conversion, but....   :)

I'm curious as to why the carbs had to be reworked so often. You specifically mentioned running an inline filter which has be wondering if you found debris in the bowls at each rebuild? Is your tank suspect? If so, wouldn't the new carbs be vulnerable too?
It is far better to grasp the universe as it really is then to persist in delusion, however satisfying or reassuring.  Carl Sagan

jefferson

I'm betting on ethanol in the fuel and yes it would affect the new carbs as well.

Walt_M.

I got ethanol resistant neoprene, viton, gaskets for mine and the carb floats are nylon so no problem there but I still avoid ethanol. That stuff is just nasty.
Whale oil beef hooked!

Kenny

      I was running three 83 visions one yellow /red along with two red and whites.  All the tanks were lined with Caswell and had no loose or free particles. No particles in the filter and I was using a Uni Filter in all three. I was using one the high mileage (110,000kms) R/W machine that was done up with a Fox single Clicker , Euro gears and whit Krauser Bags for my cross Canada runs in the fall . The Carbs on this bike worked fine and for the most part I used Premium fuel, I was running around 12,000kms on each trip. The other two my wife rode on occasion and I rode them to work as well.
   During this time and over the years I was forever fiddling and overhauling the carbs and the stumble would come and go. I don't have access to an Ultras Sonic machine (retirement) and just want an easier go.
       Cheers Kenny     
2 XV 920rh 81
1 Red/White 83
1 Blue/White 83
Bmw R100rs 84
TDM 850  92

Rikugun

Gotcha, thanks for the clarification!
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

Ron McCoy, what thickness of aluminum plate did you use for your triple clamps?  I have access to some free 1" stock, but maybe it would be better to use 1 1/4" or 1 1/2"stock. (6061 t651)
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Ron_McCoy

Mike, I made my lower triple clamp and tube clamps for the upper triple clamp from 1" 6061 T6 plate.  I used it for the same reason you're thinking of, it was available and free. They seem more than rigid enough and clamp the stanchions very securely. The lateral stiffness of the fork assembly is a terrific improvement.

fret not

Thank you Ron.  Big help.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!

Ron_McCoy

You're welcome Mike. Glad if I can help. Best of luck with your projects.

fret not

I have a question that may well have been answered previously, but if so I am not aware of it.  The question is: have you fellows with the FZR carbs had any issues from running them with the bores straight up rather than at the angle they were mounted in their original application?  The reason I ask is the float bowl fuel level is a bit different at the two different angles, and that could probably cause some tuning and or fuel starvation issues at times.  Or, . . . is that not a problem?

I have gone to the lengths of making sure my carbs are mounted at the original use angle.  Now I am wondering if I have wasted time and effort to accomplish that.  It would be soooooo much easier to just plug them straight into the rubber boots.  Also, my 'design' has a bit longer intake tract as a result.  I have no idea if that is a good or bad thing.  If it works it is a good thing.
Retired, on the downhill slide. . . . . . . . still feels like going uphill!