Points assit ignition

ETZ(including Kanuni), ETS, ES, TS, IFA-RT, BK, Saxon,

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Re: Points assit ignition

Postby Guesi » Wed Jun 09, 2021 11:04 am

Puffs wrote:Breakwellmz, ta, that's what I suspected.
Then I might suggest another explanation why it seemed to deliver more power: maybe your dynamo was acting as an electric motor, assisting your 350 twin? I'm not entirely certain it would do that, but it is certainly possible. Have a look at the schematic of how you switched it.

Guesi, thanks for that graph. Google tells me the Finnish title is something like 'Guesi ignition unit advance operation', and on the y-axis it's degrees, and on the x-axis engine RPM. Yes it is an advance curve, showing 0° advance below 1000RPM, then a linear increase to the factory-prescribed 22° (=3mm) advance at 2000RPM, and thereafter it stays constant. That might help if you have a problem with the engine kicking back while starting it, but: No, that is not what I am looking for.

What I'm looking for is an advance curve that gives more advance when the RPMs rise. The time it takes the crankshaft to rotate over a set number of crankshaft degrees (or mm advance ignition) reduces when the RPMs increase. The flame front, however, has a constant velocity, and consequently the ignition needs to happen earlier at higher revs. That is what none of the commercially available systems do, to my knowledge.



The pruducer of the ignition can program any advance of the ignition he wants.
But as a commercial product, you have to give guarantee for the product.
So it is the safest way to program it as near to the original data as possible.

And knowing the ideal timing in each rev. situation need a lot of testing...
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Re: Points assist ignition

Postby Puffs » Thu Jun 10, 2021 3:50 am

Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.
Last edited by Puffs on Wed Apr 05, 2023 8:57 am, edited 1 time in total.
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Points assist & ignition advance profiles

Postby Puffs » Thu Oct 07, 2021 4:13 am

Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.
Last edited by Puffs on Wed Apr 05, 2023 8:58 am, edited 1 time in total.
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Re: Points assit ignition

Postby parrbd » Fri Oct 08, 2021 3:16 am

Back in the seventies I had an RD400C Yamaha with points ignition. I accidently swapped the left and right carb slides when adjusting the needle position (This will keep the slides about half open) When I kicked it over it screamed its head off. I hit the kill switch. It kept screaming. I stopped it by putting it in top gear, standing on the back brake and letting the clutch out. After swapping the slides back I tried turning off the ignition whilst riding. Once I got up to a good speed I found you could ride with no spark untill you let the revs drop. This was a near new bike. It seemed that ignition timing was unimportant at high revs.
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Re: Points assit ignition

Postby DAVID THOMPSON » Fri Oct 08, 2021 4:33 am

my cousin had Yamaha 250 from the 70's
we were having problems with it fouling plugs
we put in a Bosch set from my BMW r50s
he still has the bike and he said it is still running on that 2 plugs
he put the plugs in it in 1978 and just rides it when his car is broken
and a couple times a month to keep it ride able
Dave
Dave 2002 MZ RT125+1995 Saxon Tour(500cc)
1997 MZ 660 Traveller+6/13/09 WV USA
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Re: Points assit ignition

Postby Puffs » Sat Oct 09, 2021 4:17 am

Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.
Last edited by Puffs on Wed Apr 05, 2023 8:59 am, edited 1 time in total.
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Re: Points assit ignition

Postby parrbd » Sat Oct 09, 2021 4:55 pm

I suspect it was glow plugging at high revs in much the same way high mileage car engines will continue to run when switched off, probably due to glowing carbon deposits in the cylinder.
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Re: Points assit ignition

Postby Puffs » Mon Oct 11, 2021 3:10 am

Following a biased and flawed moderator choice (someone posting aggressive personal attacks is rewarded, while my technical posts are removed - behind my back & without any justification!), I have withdrawn from this forum.
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