Lectron Powerjet installation:

Information how to install Powerjet on a set of old Lectron carburetors. Thanks to for the information!

I am almost finished with the instructions but we are Very busy. So this is it in text.
First drill a hold down threw the top of the power jet all the way threw 1/8"
next hole drill down the same hole but stop .060" before the bottom you use a .166" drill.
run tap down the hole you just drilled 5 mm x . 8 mm drill a small hole in the side of the
carb. where it indented near the top of the power jet bung and install the small barb that
was supplied with the kit.
You are done
Install delivery tube, power jet, cap screw.

Hope this helps you.



Mikuni flatslide factory settings:

RS36: Float height, 17mm. #17 pilots, #130 main jets, middle notch.

RS38: Float height, 17mm. #17 pilots, #135 main jets, middle notch.

RS40: Float height, 17mm. #17 pilots, #140 main jets, middle notch.

Expect the floats to be WAY off when your receive the carburetors from Mikuni. All mine has been in between 20 to 22 mm and that's WAY too lean, even for regular street riding. Check the floats, please!

As you hop-up the bike and it starts to flow more through the cylinder head the carbs will see a larger vaccum and by that suck up more fuel. A stock Bandit 1200 with RS36 would probably be using #127.5 main jets. With my RS40, that comes with #140 main jets, on the big flowing Lazer 5 head, I'm down to #132.5 on the main jets - that's a LARGE step. It's still a bit rich - but safe.


From (Tom Weglarz) regarding K&N Dynojet stage 1 needles on the B12:

Anders, Iv'e just installed the same kit in my 97 B-12-carbs are the same. I talked to the Dyno jet tech, you need to remove the nylon spacer from the stock needles and drill them out with a #31 drill (you can use a 1/8inch drill but the 31 makes a snug fit for assembly) . Then assemble the needles form bottom to top-stock metal washer-nylon spacer-E clip in the #3 groove-dyno jet washer- white plastic sping retainer. The original instructions say nothing of the stock bottom metal washer, it must be installed or lean midrange will result. I'm currently putting 104 main jets in (ordered from dynojet, $8) to complement my kerker K-45 silencer with a 1 1/2 in. baffle.


Jetting wisdom from Murray, Kenneth

My experience has been that having a reputable shop sort out the carb jetting by running the bike on a dyno, with an exhaust gas analyzer, can yield a significant power gain for a reasonable expenditure, when combined with the after-market muffler. Figure $200-$250 for material (JET KIT) and labor. After that, an ignition advancer,approx $40-60 (material only, as it's installation is pretty simple), seems to yield low to mid range smoothness, little or no increase in top end HP. So for around $300 (if you install ign. Advancer) You will get a real seat of the pants type increase in power, measuring approx. 10-20HP, depending on components, mechanical competence, and the optimistic level of the Dyno. Opinions / experience will and do vary.... Of course, just by typing this I have: voided the remaining Suzuki factory warranty on my Bandit, your Bandit, any.


From the beloved OldKawMan@BigBore.Antiques in alt.motorcycle.sportbike

Subject: RS & FCR carbs, jetting:

Jetting problems with jet kits exist because different headers provide different exhaust restrictions.

It would be a simple matter to re-jet your carb except for the fact that your carb is a CV type. Constant velocity carbs are great for OEM because emissions are minimized. Almost all bikes have had CV OEM carbs since 1980. CV carbs are not very useful for high performance applications. They are difficult to tune at best and non-workable depending on your motor. The basic problem with CV carbs is how it works. Airflow, vacuum, determines slide position. The interaction of the slide spring, slide air holes, diaphram, and butterfly valves can be very delicate.

Adding an aftermarket header may or may not cause problems depending on the bike and the header. A higher performance header will cause more problems. Race header such as the Yosh RS-3 can change things to the point where you may only be able to get the carbs good enough and then live with it. Most riders will deal with the slight hesitations or small dead spots that result.

Adding a piston kit or aftermarket cams may cause havoc with any idle. The flat spots and hesitations will be worse. EXUP bikes are especially prone to trouble.

Jet kits come with springs, main jets, drill bits, and instructions. What they don't come with is a chart showing exactly what you are doing for your exact application.

Re-jetting CV carbs is very time consuming. There is an alternative.

Mikuni makes the RS series carbs for normal flow applications. Keihin makes the FCR series carbs for downdraft applications.

Both these carbs are smoothbore flatslide carbs. These are real performance carbs. They work everywhere, street, track, and strip.

They cost money, especially the Keihin, but these are the carbs to use for true high performance.

I have installed probably a dozen or so RS carbs and 1 FCR unit. These things cost money $500-600 for RS and $900-1000 for FCRs.

For RS carbs the rule is the bigger the carb, the more you need to lean it out for a mild machine. I have never had to mess with the needle on these, but with a dyno and exhaust gas analyzer you could probably tweak them in a bit. For 34mm carbs running a 120 instead of the 125 it comes with is common. They come with 3 sets of jets besides the ones in the fuel bowl, a 110, 115, and 120. The 36mm come with 130 mains, 125, 120, and 115 size just in case. I have never had to adjust these except for mixture screw. I only have done one 38mm RS carb. Put that on an FJ1200. Had to go with a 130 main. The 135 was too rich for the FJ even with the 1220 wiseco kit. The FJ was more work also due to the small manifolds and rigging up the choke cable. I did suspect the needle needed dropped at least a half notch, but the owner never brought it back. I have ridden it since and I still think it's a bit rich 1/2-3/4 open.

The Keihin went on a '97 Kaw 900R with a Yosh race pipe. The guy bought the carb with a kit to use the stock ram air. The 39mm carb bolted on no jet changes. I only rode it once before the operation and then right after, but he says it works great. A very happy rider. As he should be after that. I figure 15HP cost him $1750. But it was noticeably stronger along the entire RPM range. The mid and the high is where you notice it the most. It's hard to gauge these things without taking it out in a couple different situations.

If you upgrade to a true performance header, plan on spending alot of time with your CV carb. Take your time, one change at a time, keep a good record, make all changes cold, do not loose your cool. I refuse to do it any more myself, too much patience required. I'll do RS and FCR carbs, they are easy.

I hope this is helpful, even just to get you thinking about how cost effective your mods may be. Figure whatever you spend on exhaust and intake changes you can only get 10-20 HP max. For many it will not be worth the effort and trade off with flat spots and else. Many headers and jet kits will not get you anything noticeable at all except to your pocket book.

I will admit that I would have to go with the RS-3 and FCRs if I had 900R. The cost difference between the jet kit and the RS carbs is a no brainer. Hell, I'm running these on all 3 of my keepers.

I am not telling anyone to buy anything. This is just the racers option. And also for those like me, who cannot stand to have anything stock.