Hello everyone,
So I’m encountering some issues that starts to be beyond my league. I’m still quite inexperienced and this my very first full project. I’ll try to be as thorough as possible into my set up and problems as I know you’ll ask me a lot of questions if not
Symptoms
- black smoke when accelerating
- Erratic idle (I have to play with the screw all the time to get it right)I can manage to keep it steady
- Low revs sputter and strong engine brake feeling
- mid/high revs quite ok but struggle to come back down
- engine run rougher when hot
Now about the bike
Model : CB550K3
Intake : Pods K&N (I bought this bike as an unfinished project and the air box was discarded already unfortunately!)
Exhaust : 4 into 2 with a short muffler
Carbs : 069A
Main jet : 110
Idle jet : 42
Needle : aftermarket (I’ve lost one OEM so can’t fit them but if anyone got a spare 273004 I’m happy to buy it)
Needle height : 3rd from top
Float height : 23mm
Mixing screw : 1.1/2 turns was looking like the best one
Top engine rebuilt with new pistons and rings, new valve seal, valves have been lapped
Ignition
I made a DIY LifePo4 battery that seems to run ok (though no BMS on it)
Electronic ignition from David Silver
Spark advanced system with the springs a bit retighened to make sure it comes back down.
Coils :
https://www.ebay.co.uk/itm/112789241229Spark plug caps : NGK 5K ohm
Spark plugs : NGK D7EA
Sliders don’t seem to stick and it looks like they are coming back down ok. I’ve set up the slide heights with a drill bit, the synchroniser was looking ok even though the pressure is very low. Spark plugs are very sooty but dry.
It’s a full rebuild with a lot of mods so I believe it might take me some time to get there but your help would be very appreciated. Let me know what you guys think!
Thanks
Tom