The International CBX Owners Association

RobbieAU wrote: ↑

Wed Sep 07, 2022 10:57 pm

Thanks guys, the plugs are cheaper by the 100, but optimistic me thought I would get away with 60 initially...and here we are 126 used plugs later! .

I purchased the CRS carburetors from JB Power in Japan and they came with the following settings

240 Air Jet
120 main jet
62 pilot
Air screws at 3/4 turns out
YY8 Needle highest setting 7
Size 25 slides

I now have the carbs set up like this (leaner almost everywhere)

240 Air Jet
120 main jet
60 pilot
Air screws at 1 3/4 - 1 7/8 turns out
YY9 Needle highest setting 7
Size 30 slides

I messed around for a long time with different needles and clip positions before biting the bullet and forking out about $500 AUD to purchase 6 size 30 slides. Turns out that was the key to success as the size 25 slides were just fouling the plugs after 15 minutes riding at low speed.

After yesterday's 60KM ride at speeds mainly at 60 and 100 KMPH the electrode insulators are white and the bike is running well. I will check again after a few 100 more KMs to see if the plugs turn a tan colour and report back.

I also haven't done too much riding above 3/4 throttle, so the main Jet could see some changes. It did scream out to 9000RPM a few times quite nicely so I suspect it is close.

I hope this info saves others time (and plugs) tuning their Keihin CR31 carbs for the CBX1000. I know it would have saved me 50+ hours if there was any info about tuning these carbs to the CBX out there. I had to go down this route as the cheap bike I picked up had damage to one of the original carbs and I could not find a replacement.

I am running Pipemasters exhaust, velocity stacks with metal screens and premium unleaded fuel (without ethanol) with sta-bil fuel stabilizer added. I also changed the fuel tap to a Pingel unit.

Cheers,

Rob

bobcat wrote: ↑

Thu Sep 08, 2022 1:31 am

Hi Rob,
When you are talking about slide size, are you referring to the "cutaway angle "
at the bottom of the slide ?