Hi!
Been tinkering for a while with a nice condition K5 CB750 with the great help of Hondamans' book
When I got it, it was running sort of ok, but not like I expected. Tendency to foul plugs during cold starts, no real rush at higher rpm:s, abrupt clutch engagement, weird roadholding and so on.
Stuff done so far:
- Carb rebuild with Keyster kits, main jets changed from 105 to 110. Needle clip position 4 from top - no change
- Fixing the choke linkage in order to apply same amount of choke to all 4 carbs
- New HM341:s from David Silver were installed in 2007
- Airbox vents opened up to 50% more area. Holes drilled + forming with heat gun.
- Centrifugal advance shaft trued to 0.05mm => timing became rock soilid!
- Centrifugal advancer tabs bent + weights filed => full advance timing at second marker (more advance)
- Idle mix screws at 1 turn
- Plugs changed from DR8ES to D8EA => no more plug fouling when cold
- Wheels carefully aligned including centering of front rim, new rear shocks, oil in both fork legs (!) => much better roadholding
- Steering head roller bearings
- Yamiya improved clutch kit + oil hole drilling of outer drum => better clutch operation, less slip but still some gearbox clonk.
Now the bike is a pleasure to drive, easy to start and even shows some signs of power at higher rpm. Plenty of torque at low/mids.
There are 2 problems still: when warm (only then) ther is a slight stumble when gently accelerating off idle.
The plugs are WHITE, both after a full throttle run/immediate stop and also after normal driving.
Is there anything else I should think of before going into jetting
Any advise appreciated !!!
Tommy
