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Anyone used to working on GSXR600 SRAD carbs?
Deckman001 - 19/7/20 at 10:10 AM

Hi all, as in the title, does anyone here have experience with tinkering successfully with the above carbs? I've found the cause of the non running, and it's probably good enough to drive the car, but i feel it could do with a fettle with to set up the linkages and idle screws as it's never been touched since they were put on the car over ten years ago, and I'm sure it should be a little smoother, and quicker to drop back to idle after a push of the pedal.

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Jason

ragindave - 20/7/20 at 07:17 AM

Bikes carbs in general need the needles raising this increases fuelling in the lower and mid range you should also consider putting larger jets in and you must balance them this is very important, on a bike the throttle would have 2 cables pull and return usually, without the return cable you may need to assist the return with an additional spring.

Deckman001 - 20/7/20 at 01:30 PM

quote:
Originally posted by ragindave
Bikes carbs in general need the needles raising this increases fuelling in the lower and mid range you should also consider putting larger jets in and you must balance them this is very important, on a bike the throttle would have 2 cables pull and return usually, without the return cable you may need to assist the return with an additional spring.


Hiya, thanks for your reply. The carbs now get the engine starting very easily and settle quite ok to idle after the choke is taken off when warmed up. it does rev up ok and comes down ok after but I just wondered if there was anyone nearby who could assist with the balancing of them just to make sure everything is ok based on someone who knows what is normal.

I only have a single throttle cable, the return is via the big spring just inside the throttle cable disk connection. I can twist the throttle manually and it snaps shut straight after i let go so I guess the return has been sorted by whoever built these carbs into a car use about 12 years ago.

Jason

SJ - 21/7/20 at 12:51 PM

Atspeed in South East Essex are your.boys for bike carbs on car engines. Getting the afr right at various engine speed and throttle opening combinations is the challenge. Balancing is easy.

Have you had a wideband on it?

[Edited on 21/7/20 by SJ]

Deckman001 - 21/7/20 at 02:50 PM

quote:
Originally posted by SJ
Atspeed in South East Essex are your.boys for bike carbs on car engines. Getting the afr right at various engine speed and throttle opening combinations is the challenge. Balancing is easy.

Have you had a wideband on it?

[Edited on 21/7/20 by SJ]


A wideband ?

I have put a anemometer against it and carb 4 is pulling much more air through it that all the rest are pulling. IE 1.9 when the other three are pulling 1.1 each

As said earlier, it feels basically ok, I'm just wondering about tinkering with it to make it even better hopefully

Jason

Deckman001 - 23/7/20 at 07:51 PM

quote:
Originally posted by ragindave
Bikes carbs in general need the needles raising this increases fuelling in the lower and mid range you should also consider putting larger jets in and you must balance them this is very important, on a bike the throttle would have 2 cables pull and return usually, without the return cable you may need to assist the return with an additional spring.


You were so right about the return spring, I checked tonight how quickly the carbs returned to idle after letting go of the pedal, and it's not very quick due top the gravity of the pedal, so am going to install a new spring to the pedal bar where it joins the throttle cable and anchor it to the frame work.

Once again, many thanks for your comment

Jason

SJ - 23/7/20 at 08:26 PM

By wideband I'm talking about a wideband air fuel ratio meter. It allows you to monitor the mixture whilst driving meaning you can make changes to jet sizes and needle position and see the effect on the AFR.

Fuel injection systems use an afr to constantly tune the mixture. Using one with carbs and a display enables you to set the carbs up. Doing so on a rolling road is best but it can be done without.