Hey all, I’ve acquired a very nice barn find cb350F and it developed poor running symptoms so I decided I’d refresh the engine with a bore deglaze and new stock pistons and wrings. Clearances are all well within stock measurements.
At the same time I replaced the camchain, valve seals, all other seals and one bad valve that had some degradation of the sealing edge. Bike has 17000 km (about 11000 miles+|-.
I also replaced the points and condensers with stock parts and have Dyna coils and 8mm wires with new NGK plug caps and (now) new D8EA spark plugs . I originally had DR8SL plugs fitted.
I’ve also rebuilt the carbs using all Honda parts but left the original jets in place after a good cleanup.
When installing the carbs the actuator ring broke off the choke shaft so I refitted it in the original stock position and silver soldered it in place. Needle is in the middle position and idle screw is 2 turns out. New genuine Honda filter fitted.
Bike wouldn’t start after the rebuild and #1 son pointed out that I needed non resister spark plugs so I installed the D8EA plugs and it started right away .
It’s blowing black and white smoke like a badly tuned Kawi triple and is cutting in and out on acceleration and the plugs are covered in soft black soot. It’s not oily but very dry and clearly it’s rich mixture (or ignition) related.
Spark is very strong even through the soot. Timing is set statically on the mark for both 1,4 and 2,3 cylinders and advancer is loose and free turning.
Initially I thought the choke was maybe slowly turning itself on so I tightened the shaft so that there is lots of friction between the shaft and the handle by tightening the 9mm nut that ‘manages’ the friction. So that’s not the problem, I think. ……..
What am I missing? Help and opinions please…..
