NEW CARB!

The easiest thing to buy is a round slide Mikuni...either new or secondhand, try one of the Sudco ones. I prefer a 38mm, but others recommend a 36mm carb. They are relatively cheap as carbs go.

I've seen guys fit Mikuni 40's as well, but that's pretty well over the top in most cases. Depends on whether you have a big bore kit fitted, race use etc...

There is a lot of jetting information available on the various websites for the setup/jetting of these things (36/38s) and they are ultra reliable.

You'll need to get a throttle and cable setup to suit; you can make a cable to suit the standard pull throttle assembly as well, however, it takes a bit of work. Even with a proper cable for the round slide you may have to bend the cable fitting in the top of the carb to clear the frame. A quick action throttle is also a nice side benefit...

Once you've done this you won't look back. They don't cause you any problems and they are very uncomplicated....unlike the standard carby!

SR

THANKYOU FOR THE INPUT...I HAVE NO PROBLEM WITH MODIFYING PARTS..HAHAHA...I WILL GET PICS UP HER OF MY BIKE REAL SOON!....I DO HAVE ONE MORE QUESTION REGUARDING THESE CARBS THOUGH?...WHAT IS THE BENEFIT OF THE FLAT SIDED CARB? LIKE THE ONE FOR SALE AT THUMPERSTUFF.COM...

Hi,

Quite possibly; I haven't bought stuff from Ian for ages.

You can always look at getting a second hand early MX one (wreckers), or look at what's available from MCA as reproduction parts.

At least if you get an old YZ one or similar, then you can use the YZ throttle cable as well...straight fit onto a 38 Mikuni. I have these on two of my bikes...YZ250/465G model ones...same throttle for most of the earlier YZ's anyway.

You'll have to look at what you do with the right switch block though, if you're using it on the road.

I removed mine and used a switch block with only headlight on/off from an MT250 Honda. I don't have a kill switch on the black cafe bike at all.

Cut the elec. connector from the original switch block and solder the Honda wiring to it. Cut the wiring with length to spare so you can solder it back on should you ever wish to.

The later MX ones are side pull throttles and these run the cable along the bars...these often get in the way of switch blocks a bit...

SR

I agree with Christer, the stock carb is over-engineered. I use a VM34mmSS carb from an old TT500 thats really simple and gravity fed. I've had no problems with it and it works well. My SR is basically stock with only a Supertrapp pipe and free flowing K+N air filter. You just have to remember to turn the fuel tap on when running and off when stopped. I just turn it to "prime" when it's time for a ride, which is in about 5 minutes. Beautiful day here in Southern Ontario and I got to get out there for a ride.

Hi,

No, no need to do a port job to fit the carbs...a 34 or a 36 would be fine. Personally I prefer the 38's...but it could be argued that it may be a little overcarburetted down low...by some...not me...

I am going to fit a 38mm Kei Hin CRS smoothbore carby to my new cafe racer. Actually the carby is so nice it's a shame to use it...looks better just sitting on my cabinet...like the FCR they are a carby 'work of art'.

I have the old style Kei Hin CR31 smoothbore carbs on my Honda 350 racer...they are literally bolt-on horsepower.

Back to your question...the Mikuni 36 is probably the most commonly fitted and all of them will go straight into the standard SR manifold.

If you use the larger outlet sized aftermarket Mikuni manifold, then you can carefully blend the port into the head to match the carb outlet size as a smooth lead in for the mixture. For this setup I also use a spacer that I machine from plastic or alloy, that fits between the front of the carby spigot and the rear of the head, to blend the carby outlet size into the head smoothly.

You should get a performance increase with the VMS carbs, provided that you also match it with a freer breathing exhaust and a less restrictive air filter as well.

SR

Hi,

Yes say one size MJ above and below, and perhaps the same for the pilot jet as well.

SR