Carb modification question

[nvmike24]

I seem to be in need of yet another set of carbs. Not liking the way the CV carbs react I an thinking of Flat Slides. Does anyone have any expireance with the Keihin and Mikuni Flat slide carbs? Pros n Cons other then price? They are proud of them at 3 times the cost of stock.

[JCainFJ]

 Stock carbs from a Yamaha dealer are almost $1800, if you can find them. RPM sells race engine takeoffs for $400 when he has them in stock ( this has to be one of the best deals in all of motorcycling).
I have a set of RS36 flatslide Mikuni carbs on my 89. I think they were only about $800 when I put them on. They do work very well once they are setup. I chose the RS Mikunis because they come with a "choke", I live in northern KY and a "choke" is needed for cold starting  in the spring and fall. The Keihins do not have a "choke". My Mikuni's came from Carb Parts Warehouse but they still needed a some time and effort to work on my FJ. The first problem was throttle cables, I had to modify a set of new stock cables to work with the RS's. I had to shorten the inner cable length. The next problem was the float valve was setup for a gravity feed system. The stock float valves from my BS36 carbs had to be installed in the RS carbs, and the float level needed to be set. The stock fuel delivery system will not flow enough fuel if you remove the fuel pump. I also had to sync the RS's, they were way off out of the box.
The RS's do deliver more power then the stock carbs. Stock, my FJ would only make good power to about 8,500 rpm. The RS carbs make more power all the way to 10,000 rpm.
The stock carbs from RPM are a great deal at $400, install a Factory Pro jet kit and a pair of the UNI filters and your done. Or order a set of the RS flatslides, make a few parts, move a few parts, and install some UNI filters and enjoy.

[nvmike24]

That was the info I was looking for indeed. Mods don't worry me with the cables. I figured the Accelerator pump in the Keihin's would cover the cold start.

I got carbs and uni filters from Randy on the 1100. I am thinking of going deep into the 84 and see what it'll do. Monster engine will require monster carbs! The 1200 is so original and clean I want to keep it that way. The wife likes it as it is and she will be riding it most of the time.

The 1200 has 53k on it and the carbs are loose! I synced them and in a few miles they were out of adjustment again.

[Pat Conlon]

You can have both...... but wait there's more!!!!.
1) A fully adjustable accellerator pump and
2) Full choke functions,
3) Along with easy to open roller slides,
4) Available in 36mm, 38mm and big 40mm dia. sizes

The Mikuni TMR Carbs (bring your wallet)


http://www.allensperformance.co.uk/tmr38-d2.html

[JMR]

You can have both...... but wait there's more!!!!.
1) A fully adjustable accellerator pump and
2) Full choke functions,
3) Along with easy to open roller slides,
4) Available in 36mm, 38mm and big 40mm dia. sizes

The Mikuni TMR Carbs (bring your wallet)


http://www.allensperformance.co.uk/tmr38-d2.html

They are the "Bomb" Pat. It was you that brought to my attention the FCR's are no longer available for the FJ. That being said I have had very good results with the RS's.

[nvmike24]

 
I can not find the pricing!

[carsick]

If you have to ask...

[JCainFJ]

 Mike,
It sounds like you have a plan! Living in Vegas has to make cold starts easy.
I also upgraded the ignition with a power relay, Dyna coils and a Dyna 2000 ignition system.
Please keep us posted on your build, there's always more then one way to skin a cat.

Ride Well,
Jon

[JMR]

I can not find the pricing!

The 32mm set I bought for my SOHC CB750 were around 2,200.00 with the air filter adapters. I currently run 39 FCR's on my FJ which is 1314cc. They are nice carbs Mike but I wish the accelerator pump was more adjustable. I had to modify the the cable mount on the FCR's too to better accommodate  a set of Motion Pro cables.
I have used 36, 38 and 40 RS';s on the FJ. They are very reliable and very adjustable. You can fit the stock choke cable to them. As mentioned...one cable has to be shortened. While the throttle pull is stiff compared to the FCR's you can loosen that up as well. They are good carbs and jets etc are cheap compared to the FCR's.

[andyb]

I seem to be in need of yet another set of carbs. Not liking the way the CV carbs react I an thinking of Flat Slides. Does anyone have any expireance with the Keihin and Mikuni Flat slide carbs? Pros n Cons other then price? They are proud of them at 3 times the cost of stock.

What's wrong with the CV carbs?  Are you using a built motor or have a specific issue with them?  They're pretty tunable and you could probably spend vastly smaller amounts of money on a dyno getting things set more optimally for your machine....