
I don’t do carburetor tuning as a job.
You should ask a shop that specializes in chassis dynamometers and tuning.
Test driving is just too dangerous (*’▽’)
I’m going to change the jet on the CVK carburetor.
Where can you even buy it? Let me search with Google…
What? Same as FCR? SJ and MAJ (this is MJ)
Easy to source and affordable. Carburetors really are Keihin after all…

After rummaging around, I found the SJ.
I didn’t have the MAJ, so I’m just going to upgrade the SJ from #35 to #38.

The removed jet looks dirty….
The number on this jet is
I wonder if I’ll eventually not be able to see it either??? (presbyopia)
I hope not, though it might not happen…


This nice cargo tie-down belt at 3m really boosts work efficiency.



You can pull it out smoothly (*´ω`*)


I was a bit shocked to see rust…

The jet color is dirty…..
Well, I’ll eventually swap it out for a BSR for the GS1200SS anyway, so this is fine.
*The key is not to waste time and money unnecessarily.

The PE WIDEBAND O2 sensor is probably acting up, so the air-fuel ratio reading is unreliable.
But it’s definitely on the lean side.
The moment I changed the SJ to #38,
“improved cold start” “idle exhaust pressure increased” suddenly smooth.
The more you do, the more you notice things, so it’s a carburetor you don’t want to mess with.
Stock really is the easiest.
I haven’t confirmed yet if FCR’s MAJ=MJ, so please note.
