RS flatslide installation help

[pano]

I am mounting a set of 34mm RS flatslides on my 821000sz Katana. It has a freshly mounted Kerker and I expect the push pull throttle any day now. After reading the instructions I have a few questions.

The tubes on the float bowls are not addressed in the instructions, how do those need to be routed? Are they vents or overflows?

There are 2 nipples on each carb at 3 and 9 o'clock on both sides of the intake (air filter side). Are these vents? Does anything to attach here?

I need to connect the petcock vacuum to any one of the carb vacuum ports right? (stock petcock)

When I synchronize. The instructions say "connect to the fittings ON THE CARBORETORS near the intake manifolds" I have synched my CV carbs using the ports on the intake of the head but not the carbs themselves. Do I need to connect the synch tool to the carbs here or the ports on the head as before?

Thanks in advance. the Kerker has a freshly packed baffle and sounds awesome...maybe a little loud but I am not sure since I have only idled it and cracked the throttle a few times.

[rosco15]

On mine the tubes off the float bowls route down to a catch can mounted to the swingarm. Don't do anything with the nipples at 3 and 9. Not sure about your petcock.

[Billy Ricks]

The small lines off the bowls just route down behind the transmission. They are just overflow lines. The nipples at 3 and 9 are just to get atmospheric pressure to the bowls. You can use any carb vacuum port for the petcock, and you synch using the ports on the carbs.

Good luck with the synch, it looks like a real pain, at least on my bike.

[pano]

Thanks. I think I got it now.

[oldschoolGS]

I am not sure how or why you would want to vacuum sync non-CV carbs.

Sudco specifically recommends that all smoothbore type carbs be synched mechanically rather than with vacuum gauges. The reason is that the synch adjustments on smoothbore carbs are located under the top cover of each carb, when removed this exposes a large vacuum leak to the cylinder being adjusted resulting in inconsistent vacuum levels from one carb to the next.

The recommended way is to bench sync using a small piece of wire or rod app .020 in diameter. Use this as a guage under each slide to set all the slides at the same spot.

This procedure is per the Sudco tuning manual for RS smoothbore carbs. They sell it for around $12.

Go with a dual outlet Pingel petcock for maximum performance.

Good Luck, Ed

[Billy Ricks]

I agree with Ed. All I've ever done is bench synch my carbs. RS carbs aren't about bottom end anyway.

[skip]

I am not sure how or why you would want to vacuum sync non-CV carbs.

Sudco specifically recommends that all smoothbore type carbs be synched mechanically rather than with vacuum gauges. The reason is that the synch adjustments on smoothbore carbs are located under the top cover of each carb, when removed this exposes a large vacuum leak to the cylinder being adjusted resulting in inconsistent vacuum levels from one carb to the next.

The recommended way is to bench sync using a small piece of wire or rod app .020 in diameter. Use this as a guage under each slide to set all the slides at the same spot.

This procedure is per the Sudco tuning manual for RS smoothbore carbs. They sell it for around $12.

Go with a dual outlet Pingel petcock for maximum performance.

Good Luck, Ed

I have done both methods on the rs flatslide 38's I had I used the motion pro mercury sync tool and synced the carbs at 2500 to 3000 rpm. that worked. I also just adjusted them manualy till all the slides were chattering equally at idle by ear before I had a sync tool. that also worked. I also used a drill bit to sync the slides like the method descibed above and that did not work as well for me. That metod wont compensate for any clinders that may be falling behind or jetted different or not as strong as some of the others.

[first timer]

would the above apply to 29mm & 33mm smoothbore as well, well not to mention any VM style carb. If so, couldn't you wad some gauze/cotton balls around the top of the slides to help keep air from sliping by when vacume syncing.

[pano]

The manual that came with the carbs refered to synching the carbs with the manometer, but the description is vague and only a couple sentences. I also have a soft copy of a Sudco Mikuni tuning manual for slide carbs (it is 22 pages and not RS specific) and it doesn't even reference synching that I could find.

I know how to synch both ways. Thanks again for the inputs.

[oldschoolGS]

Sudco sells a tuning manual for Mikuni carbs seperately for around $12. It is 92 pages and covers all aftermarket Mikuni carbs incl : VM, TM, HS, and RS smoothbores.

It is very informative and highly recommended as it describes how each circuit works in detail.

On page 13 they specifically cover synching smoothbore carbs. It specifically says: "Sudco recommends that all smoothbore type carburators be synched mechanically rather than with vacuum gauges or a mercury manometer" They give three specific reasons why:

1. In order to reach the synch adjusters you have to remove the top cover which creates a vacuum leak.
2. Vacuum reading are based on too many engine variables (individual cylinder compression, spark quality, timing, and slide lift)
3. Carb circuitery is throttle position sensitive, if the slides are not in perfect mechanical allignment, one carb may be operating on a different circuit from the others.

I think #3 is the key. If they are not in mechanical allignment all other reading are not going to be 100% correct.

It describes the procedure in detail and also elaborates on how to use a vacuum guage once the synch is complete to optimize the fuel/air screw settings.

Good Luck and enough said, Ed

[pano]

RS Flatslide installation (update)

This is for others that may do the same mod.

Application:
1982 GS1000sz Katana
K&N filters
Kerker 4-1 w/2 inch baffle
34mm RS flatslides
130 mains

The RS application guide says to use 36's for the GS1000 but I chose to use the 34s over the 36s because from what I have read the velocity will be greater through the smaller carb and have better metering of fuel.

The 34's (115)and the 36s (130)have the same internals except for the main jets. I put the 130's in so the carbs are the same except for the bore size.

I first did a mechanical synch.

I set the carbs up according to the instructions, pumped the accellerator pin, put the choke on and the bike started right up. Choke came off with in seconds. I adjusted the idle slightly (up) and took the bike for a ride.

Bike pulled great fron idle to near redline. I still have to do do plug chops etc but the throttle response was good. The throttle is a bit stiffer but I think the spring is adjustable.

As for power I need to take it out of my residental neighborhood to get a better feel for that but that will have to wait until after the lawn is mowed and the hedges are clipped.

The Kerker is a bit loud.

Thanks again for everybody's inputs.

[Billy Ricks]

One of the return springs has something like three pins the spring can be hooked to. I have mine on the lightest position and it makes a big difference in throttle stiffness.