Topic: '74 K 750

[gazelle]

Bike has 16K miles, my brother has spent LOTS of $$$ with a "respected" mechanic who supposedly knows these bikes. Suspected carb issues.....rebuilt and replaced many parts at least twice. Last time he had it started it ran well for about 15  minutes then crashed...pops and backfires, etc. I suspect ignition issues (45  yr old coils getting hot/breaking down ?)   "My" trusted mechanic suggests swapping to a solid state ignition. Thus my question(s): Is  solid state the way to go ?  If so what parts do I need and where do I  source them ? Approx cost for parts ? Is this a DIY job or best left to a "pro" ? Thanks for any input. Brother is frustrated and wants to sell the bike ($1K to me....nice bike...100% original, 1 dent in gas tank.)  Thanks for any input/response.

[rocket johnny]

     i'll take it for 1k !   

[seanbarney41]

Probably not the coils...Out of 13 or so sohc4's, I have yet to find a bad coil.  can you take a peak under the points cover and tell us what brand of ignition components?  Sounds like bad condensor/s.

[PeWe]

A loose wire connection? Start from point plate, blue, yellow should be properly connected, fiber washers, Blue, yellow wires connected to the main harness. Under tank black/white feeding coils. Maybe a bad plug cap?
Important if the problem is on 2 cylinders like 1,4 or 2,3 which indicate one point with its connections to coil. Only one cylinder check plug wire and cap for that cylinder.

[disco]

I've got Dyna S on my two 1972 CB750's. One runs Dyna 5K coils and the other runs Honda OEM coils. I've read that others have had problems with the Dyna S ignition failing. Ive not had any issues whatsoever so far. Both bikes start instantly. Dyna S installation is very easy.

[PeWe]

My K6 has Dyna 5 Ohm coils (black, dual output).  (NGK caps 5 kOhm)
Tried 3 ohm (green, dual ouput) but battery drained quickly with Dyna-S and 3 ohm coils.
Installed Points and Hondaman ign module. Points must be properly adjusted. Both points must be equally set which can be done with a Dwell meter, adjust points at high idle.

[ekpent]

Probably not the coils...Out of 13 or so sohc4's, I have yet to find a bad coil.  can you take a peak under the points cover and tell us what brand of ignition components?  Sounds like bad condensor/s.

Good advice and a good place to start.

[emlupi]

Check out all ignition components and proper adjustments as mentioned above. I have Hondaman’s ignition module and highly recommend it. The bike is much more reponsive across the entire rev range.