Mikuni possible replacement

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Skyguyz

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I did search the forum here and did garner some advice. My rebuild is going along fine due to a lot of good advice/opinions on this forum. Time to look close at my Mikuni 34mm round slide carb it's a little "tired." The slide kinda sticks now and then and the choke lever is wonky, the bowl gasket is crustified to the bowl flange, it's tired. Looking at the Mikuni TM 34mm flat slide seems to be a good option. Price is a tad over $100, should already fit my 34mm single mikuni flange mount, (yes/no?) The standard reasons for this flat slide are:
*An advanced design allows faster and smoother airflow through the venturi
*A strong vacuum at the needle jet nozzle results in more efficient, quicker fuel draw for instant throttle response
*Carb body accepts the power-jet and accelerator pump kits
*Use standard VM-type mounting flanges and most of the same tuning components

The Keihin FCR 35mm flat slides with rollers is a bit extreme and unnecessary I think.

So, at this stage I have a decision to make. What would you do?

Thanks again,

Sky

34mmTM flatslide.
Mikuni possible replacement
 
#1.Yes
#2.Yes
#3.Not sure, don't think there is enough length to fit the power jet.
#4.Yes.
Are you telling me that you can buy a pair of TMs for just over $200.00.?
Far out. $ 250.00 plus each over here.
Also,... check to make sure there is a proper idle screw setup, the early ones only had a screw arrangement (optional extra)
in the cap at the top of the carby, next to the cable.
AC.
 
Suggest you check if you can run the throttle cable CLEANLY to it without frame interference. It looks a little high to me.

P.S. May we ask what's you source?
 
I had the single 34 Mikuni for 15 years, one year ago a bought a pair of PWK 32mm flat slides from JSmotorsports

here is the link to his products page, scroll halfway down to see the flat slideshttp://www.jsmotorsport.com/products.asp

For $445 you can have rock solid idle, and most important a twin carb complete with everything set up that flows like crazy, and is a vast, huge, performance increase over the single mikuni.

I have had mine for over a year now and flat love them. If you are going to spend money on a new carb, maybe consider spending a little more for a fabulous twin carb set up?
 
Hummm,

Leaning this way.

I had the single 34 Mikuni for 15 years, one year ago a bought a pair of PWK 32mm flat slides from JSmotorsports

here is the link to his products page, scroll halfway down to see the flat slideshttp://www.jsmotorsport.com/products.asp

For $445 you can have rock solid idle, and most important a twin carb complete with everything set up that flows like crazy, and is a vast, huge, performance increase over the single mikuni.

I have had mine for over a year now and flat love them. If you are going to spend money on a new carb, maybe consider spending a little more for a fabulous twin carb set up?
Click to expand...

I mean, sure it's a tad expensive, but for the price, look what a fantastic, no fuss, plug n play performance setup. Still open for opinions though.
 
The TM flatslide.
They are a little taller so the throttle cable bend is a little worse.
They run nice and tuning is easy.
The teflon coated slide will stick if you ride it in the rain. I quit installing them because of that problem. Jim
 
Update.

I cleaned the slide on my Mikuni with carb cleaner and it works fine. I ordered a new choke lever, (Although not sure if it's needed.) and a new bowl gasket. For very little from Sudco. After doing some research on the single Mikuni 34mm VM carb, it seems to fall short on the total performance package. The specs on the dual Keihin flat slides from JS Motorsports just make sense on a total rebuilt engine from CNW. So ends the debate on what to do.
The help here has been nothing less than great as usual and I am very grateful for the guidance. Hummm. Now what to do with a Mikuni 34mm VM carb with complete setup for a 850 Norton. (New throttle cable for euro bars as well.) Probably the for sale section.

Thanks again guys.

Mikuni possible replacement
 
What to do with your MIkuni after you get Jim Schmidt's fabulous flatsldes?

I listed my single Mikuni complete set up on this forum for sale section, and I sold it within three days for about $250, with manifold and throttle cable and extra jets, good deal for the buyer, good deal for me, easy.

There are many people who are sick and tired of dinking with old amals who would love the simplicity of a single Mikuni set up, fear not you will sell it!

In addition to this website you can also list it on the Britbike.com forum and also good old Ebay!
 
for the pwk 32's, do you need the original throttle assembly and cable? my 850 came with a 36mm mikuni which i believe comes with all of that as a kit? i'm considering these carbs as well and just wondering if i'll need additional parts.
 
diy570 said:
for the pwk 32's, do you need the original throttle assembly and cable? my 850 came with a 36mm mikuni which i believe comes with all of that as a kit? i'm considering these carbs as well and just wondering if i'll need additional parts.
Click to expand...
No, Jim provides everything you need:

"Design by Keihin. 32mm flat side PWK Twin Carb Kit, complete with lower cables, airfilters, curved manifolds with rubber mounts and clamps, Customized and tuned for Nortons with our custom needles & jets. No modifications necessary."

Mikuni possible replacement


*More:

"Flatslide carburators simply work better and mix fuel/air more accurately than round slide carbs. We have spent many hours testing and perfecting these carbs for use in Norton twins. We designed the needles in house to match specific requirements for Nortons. Ideal main jets have been selected. Idle jets are checked and/or custom drilled in house for smoothest running. A custom lever is added to the right hand mixture screw for accessibility (see photo above). You can use your your original twist grip or opt for our 1/4 turn twist grip and upper cable. Your Norton will generally start 1st kick, run much smoother and stronger than it ever did with Amals and stay adjusted without fuss"
 
Skyguyz said:
I mean, sure it's a tad expensive, but for the price, look what a fantastic, no fuss, plug n play performance setup. Still open for opinions though.
Click to expand...

Is this JS setup plug & play? If so, that would make it very attractive. The single Mikuni setup on my '72 750 was trouble free, very close to plug & play, I don't recall having to change a thing past the idle speed. On another project, a kit to install a VM36 on a SR500 Yamaha turned into a long drawn out mess that is still not 100% sorted. Others with the same bike & kit had no problems, so possibly it came down to something I did wrong.

I too look longingly at the JS setup and would love to know just how much work I might be signing up for!

Vintage Paul, just an hour or so from running the old Norton!
 
Hudson 29,

Looks like another "Gus" style paint?

Mikuni possible replacement


Hard to tell but it looks so on your avatar.

Mikuni possible replacement


*Pardon the "thread creep."
 
I back dated my 1972 Commando visually to make it look more like something from 1952. I'm going out to the shop to work on it now and will shoot some fresh pics later that show what it looks like. What is the "Gus" style? It looks like you also got away from the chrome plate on some of the bits.

Vintage Paul
 
hudson29 said:
I back dated my 1972 Commando visually to make it look more like something from 1952. I'm going out to the shop to work on it now and will shoot some fresh pics later that show what it looks like. What is the "Gus" style? It looks like you also got away from the chrome plate on some of the bits.

Vintage Paul
Click to expand...

Yeah, I saw the "Gus" style paint on a piece of artwork by Daniel Perice. The lack of chrome on the fenders will give it a unique look.

*The "Gus" story.

http://www.classicbikeexperience.com/ya ... 180928.pdf

Mikuni possible replacement
 
WAIT !!!

While Jim Schmidt supplies the LOWER cables, YOU need to have the plastic junction box they go in, AND you need

the single cable going from the mid tank junction box up to your own regular throttle.


People coming off twin Amals have these, however coming off a single Mikuni you would not, so better order the
upper cable and 2 into 1 box from Old Britts or somebody.

Otherwise, YES, Jim's 32 mm flat slide do come with everything else, including outstanding gas flow!
 
1up3down said:
WAIT !!!

While Jim Schmidt supplies the LOWER cables, YOU need to have the plastic junction box they go in, AND you need

the single cable going from the mid tank junction box up to your own regular throttle.


People coming off twin Amals have these, however coming off a single Mikuni you would not, so better order the
upper cable and 2 into 1 box from Old Britts or somebody.

Otherwise, YES, Jim's 32 mm flat slide do come with everything else, including outstanding gas flow!
Click to expand...

I stand correctd:

Mikuni possible replacement

1) 54-902001 Junction Box, Alloy, Two into One, Barnett 12 - 8.90
2) 15-064137 Throttle Cable, EU Std Adj, 21 1/4"x24 3/8 4 - 25.57
 
I can see why you like the Gus style, it is very striking and it suites the lines of the Roadster.

My bike is not so fancy but is done in a style that was very common just after the war, a period that had some very pretty motorbikes. Here are a couple of snaps from yesterday. The side covers are not yet installed and the bike is just being run for the first time in many years. It is still full of paw prints and in need of a good cleaning.

Mikuni possible replacement


Mikuni possible replacement


Mikuni possible replacement


Vintage Paul
 
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