Which carb design is for what? Out of Curiosity

Ah! That makes sense. Any break out diagrams of flat sides around here?

DoubleDub wrote:

Ah! That makes sense. Any break out diagrams of flat sides around here?

I found this - thanks!

turboguzzi wrote:
Flats have another advantage of rollers in the slide so the slides dont stick under high engine vacuum and need less spring force to close, easier on the wrist.

TG[/quote]



If that's the case why does everyone warn not to run rs series carbs without a push/pull throttle setup?

andy9802gt wrote:

turboguzzi wrote:

Flats have another advantage of rollers in the slide so the slides dont stick under high engine vacuum and need less spring force to close, easier on the wrist.

TG

If that's the case why does everyone warn not to run rs series carbs without a push/pull throttle setup?

I don't think RS carbs are roller. The FCR carbs are roller...and $$$.

Plus, I am pretty sure push/pull throttle cables are suggested for all non-CV style carbs.

larrycavan wrote:

Patton wrote:

Don't know but been told that sometimes it's easy to tell the flat slides are working better, because they're rattling. :laugh:
Good Fortune!

That would be incorrect :laugh:

Tongue in cheek, of course, about the rattle meaning the flat slides are working better.

Regarding rattle/clack of flatslides, here are some excerpts from topic rs34's:
kzrider.com/index.php?option=com_kunena&...ew&catid=3&id=162987

...running great. The only problem I have is the noisy carbs. These flatslides are clacking around like crazy! The carbs are brand new and now have a total of 31 miles on them. The engine is tuned perfectly, cams degreed, and it still clacks at idle and while riding... don't know if I can take that noise. I'm thinking of going back to 33 smoothbores. Thoughts??

Well, they aren´t called RattleKunis or ClackSlides for no reason. They will clack on idle then it quiets down when revs go up. Syching the carbs helps a lot but they will clack.

Are your RS34s clacking while cruising above 3000rpm?

If your carbs are constantly clacking while you are cruising, that's not a good sign and not necessarily related to the carbs. IMO carb clacking has little if anyting to do with jetting or ignition timing.

My carbs clacked and my bike ran so-so until I got everyting tuned just right. Now it pulls like a truck all over the rev range without a clack or ping...but it took a while.

The clacking is the noise of the flat slides banging back and forth against the carbs body as the piston changes direction in the cyl. The cyl pressure changes from pos to neg and this actually pushes and pulls on the carbs slides, and causes this clacking noise. My carbs are fairly quiet at idle up to 3000rpm then they are a little noisy at criuse, about 4000. not bad though.

glad to hear that the clacking can be limited with tuning. That is really annoying me.

Have you ported your head? Opening up your intake ports will also make a difference. Bigger intake ports will tend to produce more clacking. Your carbs/engine will not respond too well while the carbs are clacking...

By the way, I was able to see (hear) that only the #1 carb is "clacking". What could be causing that? Getting everything synched really helped, but it is still rattling and I can actually see it moving around with the carb tops removed. The other 3 cylinder are nice and steady.

Anything else that could cause only 1 cylinder to "clack" like that?

can hear carb "clacking" and and it was suggested that I test the compression. The clacking seems to be much better now that I have synched the carbs, carbs are way better since they've been synchronized. I don't hear any clacking at all except at idle...

No clacking while cruising is good. Don't worry about the clack at idle. You'll drive yourself nuts trying to get rid of it. It's normal to have this at idle even if it's only one carb that's clacking...

one thing i have noticed with flat slide carb's is that they can be very noisy you outa hear a zx7rr with the airbox off you can barely hear yourself think.same thing with dry clutches just part of the package i guess.i think that is one of the main reasons that mikuni went to roller bearing slides on there big harley flatslides.

finally have the RS34's dialed in pretty well. The bike is running really well but the slides still clack more than I'd like...RS34 Flatslide smoothbores

that is one of the problem with flat slide carb's is the noise from the slides themselves i did a zx7rr engine job ad when i fired it without the air box to set every thing it sounded like it was coming apart as soon as i put the air box back it became quiet. but i can handle a bit of noise if it means the bike is going to make stupid power.

mine are probably as quiet as they're going to get. You don't really notice it except at idle. I still wonder how it would run with my old 33 or 29 smoothbore roundslides?

I'd like to pick up a pair of round slide Keihin RS carbs someday, but those are pricey. I wonder if the Keihin flatslides rattle too??

about the only flatslides that dont rattle alot are the ones everybody is putting on there harleys the 42,45 mm mikuni flatslides are supported by roller bearings up and down bothsides so it keeps them quiet.

If it's any consolation the RS recently removed from the KZR clacked at idle as well.

A slight clack at idle is normal for RS carbs. They shouldn't clack while cruising. If they are clacking it's a sure sign that air and fuel from the cylinder is reentering the intake port - reversion. The engine will be low on power and the carbs will be difficult to tune. Interesting things is that this situation cannot be tuned out through, jetting, ignition timing or changing carbs (changing to a round slide carb will stop the clacking but won't stop the reversion).

I know it's going to disappoint you guys but I gave up on the RS34's. I have my Mikuni 33 smoothbores back on for now and I enjoy riding it much more. It really runs well and doesn't have that annoying flatslide sound. I plan to install Keihin CR35 specials very soon.

Good Fortune!

andy9802gt wrote:

turboguzzi wrote:
Flats have another advantage of rollers in the slide so the slides dont stick under high engine vacuum and need less spring force to close, easier on the wrist.

TG

If that's the case why does everyone warn not to run rs series carbs without a push/pull throttle setup?[/quote]

RS don't have rollers. FCR does.

For anyone else like me who might be trailing a little (or a lot) behind the carb design curve, especially with regard to rollers on flat throttle slides :laugh: ---

Keihin FCR Carburetor
Click here > www.motorcyclecarbs.com/keihin_fcr_W60.cfm

[Click on image to enlarge view.]