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How to sync my aftermarket carbs?

  • Thread starter Thread starter littleroot
  • Start date Start date
L

littleroot

Guest
Tom MLC was going to help me sync my carbs but he said I should ask for tips here because he has never worked on my type.

Total virgin to engine work I have no idea other than brand name Mikuni and they do look different than the ones in the manual.

Many thanks in advance for anything you can tell us.

-Bob

Close up shot here, more, highres photos in the link in my signature.

gs-carbs-IMG_1874.jpg
 
Those look like RS flatslides which are expensive carbs. Do you have push pull (dual ) throttle cables?

Those carbs generally go for about $400 depending upon the size. 36 and 38mm are popular
 
Push-pull=yes

Push-pull=yes

Yep, it has push/pull cables. Looks like factory/original throttle system, or so I thought. Another friend did mention that being a problem with performance and I might want to look at going to a standard system for better response(?). Seems to me there is a dead area in the cable, or a bit of "play" from released to power-on, but not having driven any other bike I would not know better.

Thanks for the response!
-Bob
 
Needs push/pull

Needs push/pull

littleroot said:
Yep, it has push/pull cables. Looks like factory/original throttle system, or so I thought. Another friend did mention that being a problem with performance and I might want to look at going to a standard system for better response(?). Seems to me there is a dead area in the cable, or a bit of "play" from released to power-on, but not having driven any other bike I would not know better.

Thanks for the response!
-Bob
Click to expand...

Just read up a bit on the RS Flatsides: requires push/pull cable.
 
littleroot said:
Just read up a bit on the RS Flatsides: requires push/pull cable.
Click to expand...

I was just going to mention that. Duals for those carbs is the ONLY way to go!!!! :clap: :p

Nice rack-O-carbs, for sure! Are you going to replace all the screws with torx or hex stainless?
 
Okay....somebody explain to me why. Why are these carbs so sought after ? How are they better ?:confused:
 
Larry D said:
Okay....somebody explain to me why. Why are these carbs so sought after ? How are they better ?:confused:
Click to expand...

Some carb geek will know better than me, but my understanding is quicker response. I'm sure there are others as well. There is a reason new bikes all have flatslide instead of CV. It's just "newer" carb technology.
 
Larry D said:
Okay....somebody explain to me why. Why are these carbs so sought after ? How are they better ?:confused:
Click to expand...

Someone like RapidRay would have all the details but basically the RS carbs are mechanical, used mostly for racing because you have instant response from the throttle. The main jets can easily be replaced without removing the carbs and have an adjustable accelerator (fuel) pump that jets fuel from the intake side of the carbs in to the throat giving a real kick to acceleration. They come in sizes 34mm, 36mm, 38mm and higher but when you get in to the 40mm and up you're overall ride abilty takes a serious dive. If you want an overall smooth ride and aren't a real acceleration junkie, stay with CV carbs.
 
Isleofman, thanks for the detailed response. When the time comes to sync Bob's flatslides, we'll be using a Morgan Carbtune and a Colortune. Only the best will do! The procedure sounds much the same as my CV34's.

2500 rpm, eh? I wonder why? I usually sync my carbs at around 4000 (even tho the manual says otherwise). I (we) may give Ray a call one of these days.

In my opinion Bob's bike is running a bit lean. His pipes are blue, and his plugs are white. Post those pics Bob. He's running B7ES plugs that the PO installed. Any comments on that?
 
A colder plug.. doesn't make too much sense if no other mods. Normally you'd run a colder plug for track use or something.

Dan :_
 
This seems to support how my bike runs: it likes to go fast and spits an coughs sometimes when I want to cruise along in the 3000-4000 range.

I would like to adjust the jets to cure the lean condition but I cannot find a manual online. The manufacturer seems to have pulled it.

Can anyone help me find docs on these Mikuni flat slides carbs?

Thanks,
-Bob

don_gibb6512 said:
Someone like RapidRay would have all the details but basically the RS carbs are mechanical, used mostly for racing because you have instant response from the throttle. The main jets can easily be replaced without removing the carbs and have an adjustable accelerator (fuel) pump that jets fuel from the intake side of the carbs in to the throat giving a real kick to acceleration. They come in sizes 34mm, 36mm, 38mm and higher but when you get in to the 40mm and up you're overall ride abilty takes a serious dive. If you want an overall smooth ride and aren't a real acceleration junkie, stay with CV carbs.
Click to expand...
 
littleroot said:
I would like to adjust the jets to cure the lean condition but I cannot find a manual online. The manufacturer seems to have pulled it.

Can anyone help me find docs on these Mikuni flat slides carbs?

Thanks,
-Bob
Click to expand...

I'm guessing you have the 36mm (D3K) RS on your bike. Best way to proceed IMHO, would be to check that the jet sizes and settings currently in your carbs confirm to the info provided by Mikuni, for your specific application (GS1100), in the table posted by Isleoman. I have the same info too....maybe a bit easier to read.
http://www.carbparts.com/mikuni/mikuni_rs_standard_tuning_specif.htm

I plan on using the recommended jets and settings as a baseline, and tune from there, if necessary.

Tony.
 
your gonna tune those carbs just like the old mechnical carbs like on my 77 gs 750 ,they are the mic mechanical [imo the best . easiest to work on and no expencive rubbers to mess with ] those carbs dont belong on that bike and im sure youll be happy with them but they would be much better on mine .lol really nice set . they will really wake up that bike . smooth as glass if correct , very good throttle responce and smooth all the way through the twist of the wrist

Rodman
 
Those are excellent carbs when set up right.
The lower nut on the closing cable adjuster should be locked dead tight.
If this one comes undone & drops down the cable it prevents the throttle closing - I've seen one racebike written off like this and another close call.

Greg T
 
while we wait on rapid ray to respond and tell us everything we ever wanted to know about the complete history and workings of the mikuni radial slide smoothbore carberators......
lets take those 20 dollars worth of air filters and throw them in the trash.
why pay 700-800 for carbs and choke them down with a set of chrome eee emgo's:confused:

also,
you do not have to run push/pull with radial slides..
its not like theres a radial slide push/pull throttle cop gonna hunt you down and give you a ticket:lol::lol:
 
I agree 100 percent about the filters - so often those things spoil an otherwise great job.
I'd be reluctant to run RS flatslides without a return cable. When they came out they quickly gained a reputation for vacuum sticking at awkward moments - undoubtedly they can be run like that - and I sure hope there are no cops in Mikuni's pay - but I'm old enough to worry about things like that.

Greg T
 
Please tell me which ones I should get. I'm already in this thing for over $2k, what's another $xxx?

blowerbike said:
while we wait on rapid ray to respond and tell us everything we ever wanted to know about the complete history and workings of the mikuni radial slide smoothbore carberators......
lets take those 20 dollars worth of air filters and throw them in the trash.
why pay 700-800 for carbs and choke them down with a set of chrome eee emgo's:confused:

also,
you do not have to run push/pull with radial slides..
its not like theres a radial slide push/pull throttle cop gonna hunt you down and give you a ticket:lol::lol:
Click to expand...
 
littleroot said:
Please tell me which ones I should get. I'm already in this thing for over $2k, what's another $xxx?
Click to expand...

if you can afford K&N's...
buy a set of 4 offset ovals for a 2 1/4" throat.
there are some non washable K&N look a likes out there for around 60-80 a set that are really good filters.
check with jay at APE.
as far as a push/pull.
tighten all the throttle springs to the max..
i have never nore has any one of my customers ever had a major issue with vaccum sticking on the RS series on the street or strip when the springs was tightened up.
if someone wants to complain about heavy throttle pull...
either grow a pair or go back to vaccum carbs with a airbox and a silly bar!
 
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