RS Carb data

can anyone tell me where i can find info on tuning and rebuilding Mikuni rs carbs ? id like to know more about tuning the accelorator pump , and how to rebuild them as well.the way the plunger rod is set up now ,they wont sqirt till 1/2 throttle. Is that right?

Post edited by: mark1122, at: 2007/11/02 00:48

Howdy Mark. I got TM33´s, also flatslide etc with acc. pumps too. I´ve found good info here:

www.mikuni-topham.de (but you might have some problems with language)

www.factorypro.com/tech/carbtun.html

www.mikuni.com/fs-tuning_guide.html

ACC pumps are a pita if they are set to work on low rpm. They can flood the engine when driving in traffic which usually means that you have to pump the throttle. I set my pumps the same way you them set now ie from 1/2 throttle up.

Mik kit #: RS34-D21-K
Application: Kaw KZ 750, Z1-KZ1000
Cylinder Spacing: 77-93-77 (700-17011 Mik throttle shaft #)
Spigot OD in MM: 40
Main Jet: 115 (N100.604 type)
Jet Needle w/clip position: 9DZH1/9DZH05 -3
Needle Jet: P-4 (Jet #568 type)
Pilot Jet: 17.5 (VM28/486 type)
Mix Screw: 1/4-1/2 turns out

Thanks Fin. I read some good stuff on those sites.I found a good manual for the hs40's on the mikuni link that will get me started.
George.Thanks I knew i could count on u. are those from Mikuni or your recomended starting point ? The main looks small for my ap.I was thinking i would start with 135's .i'm new to accelorator pump setup .Your advice would be greatly apreciated.

Those are Mikuni specs and if I know anything about Mikuni specs, they will be fairly useless... there is no indication about what air filter or pipes or anything of the sort... only a baseline recommendation. The #135s sound too big... I would start at #122.5 or so. See if you can pull redline first before drowning your spark plugs.

I started with 132's on my vm33's(actualy they measure 34mm. what do yours measure George ?)and the bike pulled harder as i increased sizes, untill i got up to 147's.the smallest mains i have here ar 132's so i will try them and go up or down from there i guess?
Why is it that newer bikes can run such large carbs and not suffer the same low end problems we see with the kz's ?

Z1109R Fin wrote:

Howdy Mark. I got TM33´s, also flatslide etc with acc. pumps too.
ACC pumps are a pita if they are set to work on low rpm. They can flood the engine when driving in traffic which usually means that you have to pump the throttle. I set my pumps the same way you them set now ie from 1/2 throttle up.

That is good to know about the pumps Fin.Thanks Anything else u can think of would be helpfull.Did u set the jets up as best u could without the pump activated,and then start to work with the pumps ?
What are the TM"s off of,size? and how do u like them?

use of big carbs is because of the 4 valve heads. more air flow without loss of air speed.

mark1122 wrote:

Z1109R Fin wrote:

Howdy Mark. I got TM33´s, also flatslide etc with acc. pumps too.
ACC pumps are a pita if they are set to work on low rpm. They can flood the engine when driving in traffic which usually means that you have to pump the throttle. I set my pumps the same way you them set now ie from 1/2 throttle up.

That is good to know about the pumps Fin.Thanks Anything else u can think of would be helpfull.Did u set the jets up as best u could without the pump activated,and then start to work with the pumps ?
What are the TM"s off of,size? and how do u like them?

TM´s are originally from a GSXR. The carb spacing is almost the same so they fitt relatively OK. Yeap, I started with tha ACC off. I had so many problems in the beginning with air leakes everywhere so I almost gave up. After I got some idea how to set them up I´d never go back to BS34´s. OK, lost some low end crunt but oh-boy it pulls like a maniac upto red line.

To finally get them set propely I just bought a Carbtube manomater for synching them and will also purchame a A/F -ratio meter to get the jetting right. It´s a real PITA to do otherwise....

Post edited by: Z1109R Fin, at: 2007/11/05 04:15

Fin.
How much are the af meters? i was talking to a local guy with a dyno and he says he will put an af meter on mine and run it on the dyno to set up my carbs.Just a thought but this may be better than buying your own af meter ?i will get mine close then give it to the dyno guy to set up.he can chech timing and such at the same time.
Nads . that is interesting. i did not know that. wouldnt 2 valves give u more area and therefore less velosity ??

A/F meters from FMI start from 150€ up.

www.fmi.vtoy.fi/

Running it on a dyno would prolly be better but I just kinda like DIY and experimenting. Thats how you learn.

Mark sometimes i think your messing with me ... combine the two ports from a 4 valve head back into one and the air speed will be slower. Outside the motor is atmospheric pressure, the engine piston creates negative pressure. Try to create enough negative pressure with a given displacement, and one huge port hole... have to be hummin pretty good and at slow piston speed, very slow air speed. Too much port erea. Take two smaller ports and the air will move faster through them. Even when the total combined erea of two ports is greater than just one. AND I just made that up, but it sounded good.:dry: