So I had the carbs ultrasonic cleaned and pilots set through the factory settings (currently 1.75 turns). The bike runs with a noticeable amount of vibration during the day, and perfectly smooth at night in the colder air with a power gain for sure.

Does anyone have any ideas on tuning to gain the smoothness during the day? I suspect its something to do with 1 or 2 cylinders running slightly quicker than the rest, and the cold air being more dense brings slightly rich mixture closer to stoich.

Bike has paper filter, dnd slip-on, and jets 138-140-140-138

 

Hi. Since the carbs were totally disassembled, did you sync the carbs after reinstalling?

 

Of course
I even benchmarked my gauge style manometer to account for the discrepancy between the gauges.

 

Hi , is your bike running rich , that is carboned plugs?

 

Hi I haven't pulled the plugs yet so I'm not sure, but I do get the feeling that it might be slightly rich. I'll pull the plugs tonight to check for sure. If I blip the throttle the rpms drop past the idle rpm a little bit and then return to normal idle rpm. I read somewhere that its an indicator of running rich. The exhaust doesn't smell of unburnt gas though, and it pops on decel.

 

Yes could be Air filter, Float level but I think the Jets could come down to !35 and 138 to help cut down on the richness , the cold air being richer does help the running at night , but not helpful during the day, maybe the plugs will point to that

 

For some reason I thought canada f3's stock jetting was 138-140, but I checked the manual and must have been mistaken. I'll look around for stock jets.

 

Yes if your going back to stock the 2 turns out on the pilot screw should help as well with the idle and pre jet

 

So an update to what's going on. I just finished a second round of ultrasonic cleaning and installed stock jets 135-138-138-135. I also deleted the air solenoid and the heater crossover tube, and repacked those stupid ****ing mini filters that connect to the diaphragms with foam because the original was gone and **** was getting in my carbs. I bench calibrated my gauge set and sync'd bang on. It was too lean at 1.75 turns and better at 2, but I think another quarter turn will be perfect.

I feel like the bike has been neutered now though, not near the pep across the rev range compared to the 138-140 jets. I'm thinking of trying 138's on all four.

 

There is a difference in jetting depending on the year of manufacture. For the 49 state US\Canada CBR 600F3 -- 138-140-140-138 is the stock main jetting for the '97-'98 model. 135-138-138-135 are the stock jets for the model years '95-'96.