cb500 non stsrter

[blade918]

hi all hope someone out there can help i bought 1973 k2 cb500 four usa model very rough spent 1 yr cleaning stripping repainting etc came to start engine fired on all 4 cylinders then nasty noises turned out 3 gears broke engine out again srip new gears rebuild back in frame pressed starter fired only on 1 and 4  swapped blue and yellow wires to coil 23 run ok not 1 and 4  found fault on ht leads so bought new coils and condensers points ok new plugs  checked for spark without plug caps sparks on all cylinders, plug caps back on will not start battery low at this point so charged it up ,fully charged switched on no lights on panel bike dead ? checked fuse blown new fuse
all lights back on pressed starter fuse blown put new fuse in now turns over but will not run  stood looking with ignition still on saw blue wire to coil smoking turned off swapped blue and yellow wires yellow one smoking thinking must be a short on blue fron points to coil by passed this wit a wire made up turne ignition on this smokes as well so no short on blue wire in main loom i am lost at this point anybody out there any answers many thanks blade918

[McCabe-Thiele (Ted)]

Not trying to insult your knowledge - are you sure the points are connected correctly in terms of insulation where the condenser & coil feed wires fit between the points spring etc?

Not sure about this idea but do you have a good earth connection between the engine & the frame fuse blowing indicates a dead short somewhere or a poor earth using the next best method of completing the circuit..

[Bryanj]

Agree, bad earth, possibly bad coil or wrong connection at coil

[blade918]

thanks for replys points are good wiring not touched it did fire up and run ok but had to strip down re broken gears wiring is back exactly as was new condensers new coils earth at coils paint scraped back so should be ok  there defo a short somewhere ive put a 20 amp fuse in temporary and the red wire from battery to fuse gets hot i admit electrics is a dark art to me so help needed thanks

[McCabe-Thiele (Ted)]

Putting a bigger fuse in is a bad move tbh.
You risk some wire melting elsewhere or a fire in the worst case

Just a thought, I would avoid using the electric starter due to the current stress in a potential earthing issue. When you check the static timing with a bulb does it all check out.
Are you getting a spark at the plugs?

[blade918]

hi spent another 2hrs with a elecrician double checked everything turns out one of the new coils is faulty bugger wasted about 8hrs now will get replacement let you know how that works

[McCabe-Thiele (Ted)]

Might help others if you name the coil brand you used so we can steer clear unless it's definitely a one off.

[blade918]

sorry for late reply just got coils off site on e bay he changed them for different make did not have a name on others.
bike runs starts ok now but i have a misfire at 4000 revs and above no 4 plug gets really sooty i have stripped carbs again found all brass ware to floats wer all miss shapen so straightened them all out set floats at 22mm changed plugs round no4 is still the same obviously rich but cant fathom why needle set at 3 as in manual also when running come to a halt it can be ticking over from normal up to 3000 carbs are returning back to original place every time so fuel getting in somewhere when throttle closed ?
any ideas thanks

[McCabe-Thiele (Ted)]

Worth reading the post on/thread about hanging throttle started by Nigel (K2-K6).
The thread has had over a thousand reads in quite a short period !
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Link here.https://www.sohc.co.uk/index.php/topic,31510.0.html