1960 kmz 750 ignition set up
Posted 13 June 2017 - 09:00 PM
Posted 14 June 2017 - 03:18 AM
Posted 14 June 2017 - 07:08 AM
Posted 17 June 2017 - 05:48 PM
Just an update on the ignition(or, more accurately, lack of ignition). Got hold of a great big Harley coil from an EVO, the guy at the Harley shop got curious and sent me the coil to try and pay him later or return it whichever suited me. He got quite involved in the whole situation and it was only the matter of 400km that separated us that stopped him from coming over and helping out personally. Anyway I installed this black brick sized gadget under the tank checked all connections, primed carbies, and hit the switch, there was an ignition from one cylinder when I turned the switch on, clearly I had spark. Kicked it several more times and it fired, once more and it fired and continued to run, but only ran well when I "unchoked" it. I remember another thread that went through the whole process,valves,carbs, ignition etc. so I am going to start from scratch, I will also try the points again with the other Harley coil that the Harley guy sent me.
but first... When setting the EI should I set the sensor to fire the coil at TDC or 9mm BTDC or 6mm BTDC or 36 or 30 degrees BTDC, all of which I have seen somewhere or another. I ask this since I did advance the timing when it was running and the engine certainly did run better (no backfiring and a much smoother rhythm) and accelerate more crisply.
The other problem I have is the kickstarter, it only just catches at the end of its travel, and it will not fire unless the motor is at exactly the right spot to take advantage of the limited kick, I know this is a "remove gearbox and replace bits inside" repair. Have NOS (supposedly) Dnepr gearbox coming from Germany to replace that box while I repair and rebuild it.
Finally, thank you all for your help, from around the globe you've adjusted and started my bike by remote control, several times now, and I am another step closer to riding rather than restoring it.
Posted 17 June 2017 - 06:58 PM
If you are only getting spark on one side you probably have a bad wire or connector on the non firing side, or a plug that is shorted by carbon. The two plugs are wired in series and the current will take the easiest path to ground. Usually if you unhook one plug completely so it can't fire the other side won't work either as the circuit isn't complete, but this can cause the coil to fail if there is no safe path for the spark, hence the safety spark jump points on the Russian coils.
Posted 18 June 2017 - 01:05 AM
I kinda worked that out for myself through trial and error, I have had the motor running countless times now and every time I stopped it to adjust the timing I had a hell of a time starting it up again. Set up the phone to video the EI while i kicked it over and discovered the cause of much of my problems. Kickstarter. The motor was rocking back and forth when I kicked it "over". I had not enough teeth on the kickstarter to actually turn the motor over. After carefully positioning the motor and starter in the optimum spot to make the most of the limited grunt that gets applied I could get it started very easily, which is a pretty good endorsement for the motor and the ignition. Then the kickstarter finally gave out, I now have no means of starting other than pushing it which I don't want to do as there is obviously bits of kickstarter cog hanging around unrestrained waiting to annihilate my gearbox. Thankfully I have the new box on the way.
Just have to convince the boss that it would be a good idea to buy another motor and rebuild that as well so that I would have a complete spare powerplant to change out in the event of any major breakdown or maintenance. That will definitely be a lot harder than getting the ignition to work, even with the collective brains trust of this forum.
Posted 18 June 2017 - 08:12 AM
This bike will take over your life.
Don't ask us how we know...
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Posted 18 June 2017 - 05:11 PM
I hunted around and found the problem with the kickstarter. Thread called "M72 Assessment", what a great Photo Essay. I can't wait to get into my gearbox now and I definitely did the right thing getting a spare one. I'll be able to ride it and repair it at the same time... (maybe that should be "concurrently"). And I can pushstart it with no fear of lurking bits of kickstarter waiting to ambush my gears.
In the meantime there is a neglected Royal Enfield that is in need of a bit of polishing and re-assembly, I'm going to have a crack at rewiring that with the leftover cloth covered wire from the M72.
Posted 20 June 2017 - 08:19 PM
Posted 22 June 2017 - 12:46 AM
All I know is that it is a Dnepr gearbox but with no reverse, NOS from Germany. I am hunting around to find if I need to get a longer or shorter cardan shaft. From what I have read there are three different lengths of wheelbase for the M72 and mine has been refreshed with some Chinese parts. I am sure that the forks are Soviet and the frame is also, the battery holder is the smaller earlier one but the frame number has been over-stamped. I am certain the frame is older than the motor, (K750 with the older gearbox with no reverse, and 3.89:1 final drive ratio) which appears to be added when the final drive was changed and the chair removed. I will try the new gearbox and see if it is better or worse than the old but keep both in good order as a spares inventory is worthwhile having particularly for big ticket items like motors, gearboxes and final drives. I don't know about where you are but where I am the rubber suffers, to hot and dry, so I have a collection of spares wrapped in plastic and half-oily rags.
As for freight I have found that the eastern bloc countries tend to be cheaper than the traditional European countries and I have found that dealing one on one (ie not shops) Latvia has been the best, that could just be circumstantial however. America is easy but prohibitively expensive freight-wise, I also keep an eye on Sidecar-pro in China, Ben is Australian and has had me pay into his account here on occasion, delivery is quick if you need it. An added and unexpected bonus of restoring this bike is that my research/detective/computer skills have improved exponentially.
Cheers and good luck
Posted 07 July 2017 - 02:59 PM
Posted 08 July 2017 - 01:54 AM
For example a mechanic who can repair a VW Beetle or Citroen 2CV should be able to setup your engine without trouble.
Posted 08 July 2017 - 04:57 AM
Posted 09 July 2017 - 09:47 AM
I replaced the gearbox on my bike and the replacement is the same length as the removed box so I did not have to adjust the cardan shaft, I had to remove and replace it completely as it was the victim of an atrocity by a P.O., then it is pretty much roadworthy and register-able (fingers crossed).
Posted 10 July 2017 - 04:28 AM
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