type 5 electronic ignition on K750 advance/retard

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usaaf14
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type 5 electronic ignition on K750 advance/retard

Post by usaaf14 » Tue Jul 31, 2012 4:08 pm

Hi all,

I have fitted a russian electronic ignition to my K750. I think it is a type 5 with the led to aid timing setting. The rotor is different to the ones I have seen photos of on this forum and elsewhere online in that it is the reverse design (it looks like the top of a lucozade bottle with two spaces cut into its circumference, only made of metal) see photo attached.

I have set the timing as follows:

1) remove ignition cover to access ignition module
2) remove spark plugs
3) jack up rear wheel
4) put bike in 4th gear

4) looking into the cylinder through spark plug hole with a small bright torch and set the piston top dead centre (TDC)by turning rear wheel slowly.
5) turn on power to ignition module

6) loosen rotor locknut to allow adjustment of rotar disc clockwise or anti-clockwise
7) align one of the cut-outs in the rotor circumference with the hall sensor so that the LED turns on to signify firing point.
8) Tighten rotor locknut and use loctite as it's a poor way of securing a rotor in my opinion!!

Following tickling the carbs the bike starts on 2nd or third kick without 'priming kicks with spark off'..


Now, what I need to know and cannot find out online is how to set the advance or retard.


I know it involves loosening the two electronic ignition module fixing screws and twisting the 'puck'left or right using the timing marks but by HOW MUCH?????

I don't want to over-advance it and burn out my pistons.

I can advance it until it runs at it's fastest and perhaps roll it back a touch.


I roughly set the new PZ28Ds jetted for SV engine on this K750 to get bike starting but normally when setting mix and speed screws you would screw in the mix fully clockwise and adjust the speed screw to achieve a low idle (other cylinder grounded) then rotate mix anti clockwise to achieve max revs followed by re-adjusting speed to a nice steady idle.

I did this on the M62 and it worked great with nice brown colour on the plugs and good starting.

But while setting the carbs on the K750 I couldn't achive a max rev as there wasn't much difference in engine speeds while adjusting at all.

So I'm thinking the timing needs to be advanced to achieve max revs. You see where I'm coming from?

So what do you guys suggest? The bike is starting fine and running very well but do I need to advance the timing????

This info is not online that I can see!! So help and advice greatly appreciated.

Eugene.
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Scott
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Re: type 5 electronic ignition on K750 advance/retard

Post by Scott » Wed Aug 01, 2012 1:31 am

You're pretty close except you want the LED to come on before TDC, not at TDC.
Otherwise, it's firing late, it'll have no power and it'll get hot because the fuel will still be burning off as the exhaust valve is opening and there won't be a good heat transfer to the head for proper heat dissippation. The problem is that there's no flywheel peep hole like on the OHV models. The oldschool way to do it is pop the end cap off the jug and measure the piston clearance (6mm-8mm) according to the R-71 specs given in the link. So basically, you want to set the pistons at the BTDC position then adjust the ignition plate until the LED comes on. With the old manual ignition, none of this was necessary.

http://www.changjiangunlimited.com/tb93.htm

It sounds like you've got the carb procedures down pretty well for setting the idle, so I don't think the problem is there.
Scott Pell
gspell68@gmail.com
http://sites.google.com/site/foilheadz/
1951 KMZ K-750 (The Bull, БУЛ)
1962 KMZ K-750 (The Beast, БИСТ)
1959 IMZ M-72M Solo Rust Buc-Kit Bike

Cheap - Reliable - Fast
Pick any 2 and the other one won't apply!

Ural Australia
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Re: type 5 electronic ignition on K750 advance/retard

Post by Ural Australia » Wed Aug 01, 2012 5:08 am

Are you running 6 or 12V ?

usaaf14
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Re: type 5 electronic ignition on K750 advance/retard

Post by usaaf14 » Wed Aug 01, 2012 6:14 am

I have converted it to 12 volt. Its a genny from a fiat 126 I think and electronic reg.

Im going to put a car battery in the sidecar and run from there. This system is designed for car use so no problems there. I am wiring in a battery changeover switch so I can transfer the charging circuit to the conventional battery in its proper position on the frame as a backup.

This electronic ignition has timing marks on it for retarding or advancing the spark.
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Re: type 5 electronic ignition on K750 advance/retard

Post by PeteT » Fri Aug 03, 2012 12:10 am

You need to set the static timing to about 5 degrees BTDC, and the electronic ignition will take care of the rest, as it has only a set amount of advance built into it.

PeteT.
05 G/U currently running 42/130 jetting, 20/50 GTX in eng. and trans and 75/90 dino in the final, homemade airbox using a Fram 3717 flat element, homemade 2 into 1 exhaust, 42 psi in the pusher, 32 psi in the other two, and now running a manual advance dual breaker point ignition system.

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Re: type 5 electronic ignition on K750 advance/retard

Post by Dnepr K750 » Mon Aug 08, 2016 4:15 pm

Having trouble with my microprocessor ignition (12V) on my K750. Ihave removed the cylinderhead, and TDC is 7 mm from the edge. BTDC is as far as I know 6 mm away all 13 mm from the edge ... Here it must provide spark with Puch'en at 0 degrees. BUUUUUT it is VERY hard to start. Alternatively (I am told) to do so by TDC and then put Puch'en minus 5 degrees? ... It should be mentioned that engine runs great once started - but when i finally does my kickstarterleg is completely smashed, so I can hardly get up on the bike
Therefore ........ I've done something wrong, but I can not find fault - and it's driving me crazy. Hope you have ideas?

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Re: type 5 electronic ignition on K750 advance/retard

Post by Scott » Tue Aug 09, 2016 1:58 pm

Weak battery???

Don't ask how I know...
Scott Pell
gspell68@gmail.com
http://sites.google.com/site/foilheadz/
1951 KMZ K-750 (The Bull, БУЛ)
1962 KMZ K-750 (The Beast, БИСТ)
1959 IMZ M-72M Solo Rust Buc-Kit Bike

Cheap - Reliable - Fast
Pick any 2 and the other one won't apply!

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