New ignition system: need advice!

[900tlc]

Follow up,if I had the right instructions when ordered,and requested.I dont think I would have got into a problem.Many thanks to mhr 900 ss .My instructions I got off the Sasche web site.I was seeing red alright but not an LED
I checked the alloy magnetic trigger and centered the scribed line under the "S" mark to the key way on the crank about 20 degrees out! Not sure why, that has happened. Switched the ignition on, and turned the crank clockwise. Yellow LED out,checked front cylinder for TDC,correct . Nipped up grub screw and rechecked all good. Green LED lit ,hand crank again clockwise ,Green LED out,checked TDC on rear cylinder, correct.
Checked several times again,because its a real pain putting the starter gear back together again.
Just to put a spanner in the works.....a little red LED comes on ,at the pickup PCB,just to add to the confusion,probably to indicate that its working?
Watch this space,for the final out come......

[ashleyf]

Rick, and others. My 76 900 is now at the point where it starts (mostly) with one or two kicks. After a short ride , stop for coffee etc , it starts perfectly . I am still nervous about it and my ability to get it going once stopped.

Soooo.. I was at a returning riders course , nice group , good instructor. Kept the bike idling for a bout 15 minutes, no issue till I stalled it . Then there was NO WAY I could get it started again. Tickling, then full throttle in case I had flooded it etc . NADA. Finally gave up , had a debrief re my riding proclivities and then went and tried it again.

On turning the key on , there was a slight 'puff' noise from front cylinder . Did the normal tickling , 2 twists First kick was a mild backfire. Second kick was a GO.

I thought originally that maybe the plugs were oiled up , but then why would it start so easily once it had cooled down.?

My thought is that the Sasche may have a heat problem . Have a replacement unit that I will use , but before I try it , I thought I would ask the brains trust about any thoughts.

The fuel , carby and electrical system have all been cleaned , measured and given the all clear . (not by me BTW, but a proper ducatisti vintage mechanic

[rjk40]

Best guess here, is that a swapout of the presently installed unit will eliminate some unknowns for sure;
that's wht we here sometimes call it a "swag". There are times when the process of elimination trumps
trying to diagnose the issue. I will be very interested to know how that goes. Is your 976 900 originally a Bosch
ignition? Good luck, fingers crossed here.

[ashleyf]

Yeah, think I'm heading that way. Not the Bosch originally . All work done by Brook Henry, so very confident in the workmanship. Been a dream to ride , much better than my previous 78 (sold in 2002) .

BTW, fitted a sidestand to it. After 2 hrs, my hips needed a break and am much happier knowing the bike is supported whilst I limp off. !

[81mhr900ss]

If cooking your Sachse unit is a concern, I'm interested to know where it is located. Mine is velcroed to the rear mudguard adjacent to the battery and seems to keep reasonably cool despite its proximity to the rear head.

Did you read the troubleshooting section of the Sachse manual? https://www.elektronik-sachse.de/manuals/Z61-ES-en.pdf

Once my bike is hot, I never touch the ticklers, just give it a squirt or two and kick it over. Your bike may well have been flooded and after a few minutes, the heat of the engine will evaporate the gas. Why did you idle it for 15 mins? Idling for too long, especially with 40mm carbs is asking for trouble, especially if your tick-over is low. Also, our old air cooled motors need to move to keep cool. I added an oil cooler to mine after my second hot summer; fine on the highway but my old girl was not happy in town traffic.

[rjk40]

All good points, Rick.

Thanks for the tips.

[ashleyf]

Thks Rick fair point, re idling. Got taken over to a stretch of track and then talked to for too long. Good lesson.
Sasche is above battery.

It is a learning curve , must admit that my old Pantah was simpler!
Determined to conquer it.
Nearly there...

[ashleyf]

Long chat with Brook H, reckons it should be able to idle for longer as long as it's not too hot. 40 degrees . ( He's based in Perth ,OZ remember ).
Anyway ,swapped over unit. Just had to adjust dip switch, left setting at 5. Original was 4 .
Started first kick. Ride for an hour . Traffic , but 60- 70 K speeds as well.
Stopped. Wouldn't start. No real feedback , bit of a kickback.

Left it for 10. A bit offarting , mild kickback. 6 kicks later it was roaring.

Pickups ,?
This rebuild is 10 years old, and had bugger all riding done cept yearly oil changes and carby checks. Maybe 200 K when I got it.
Dream to ride, just this bloody hot start issue.
Will keep you posted.

[rjk40]

Yowza!

Yeah, if you swapped out the box and the problem persists, that leaves the pickups, coils, and wiring.
What brand of coils are you using?
Still a bit curious, as Rick mentioned, about the heat, but if it runs fine once started, who knows?
I would have thought that the box would be the most likely heat-sensitive component part, although
the pickups do sit in a constantly "warm" environment.
Seems like cooling off is a positive catalyst.
Unless the symptom is hiding the real cause; wouldn't be the first time.
This is an example of "mystique".
Wish I had more to offer, but if I were in your place, I would try new pickups as well.
Once you do find the culprit, and I know you will, posting it may save some other bloke from
going prematurely grey.
Mebbe Rick will see this and offer some more of his wisdom. My experience tells me that he has a bunch.

[81mhr900ss]

One of the Sachse selling points is that it is an electronic ignition with a selection of built-in advance curves. All have one thing in common: no advance at start. This means that as long as the motor is turning due to being kick or electric started, the spark is not advanced at all, triggering a spark at TDC so there should be no kick-back. Kick back suggests that the timing may be just slightly off; it does not explain why the bike is not happy starting once hot. Adjustment of the pick up plate is easy. From the manual:

Bring the piston of the horizontal cylinder approximately to the bottom dead centre. Then turn on the ignition and turn the crank slowly clockwise until the LED turns on at the lower sensor (maybe it will be on already when the ignition is switched on) and then move the piston exactly to TDC position. Now rotate the pickup plate counter-clockwise until the LED turns off at the lower sensor. Now the correct position is achieved. Do not forget to tighten the screws in the pickup plate.

It helps to decipher this a little; the goal is to have the lower sensor LED turn off at front cylinder TDC (doesn't matter which TDC as it's a wasted spark system). It's easier to do this on the older non-Bosch bikes because the pups and trigger ring are both on the engine side and the test LED is on the pickup circuit board.

[Tinkerbell]

Hi Ashley
My 860 is harder to start esp when medium warm. I am finding that when really warm I just crack the throttle a bit and kick, trying not to excite the accelerator pumps. If its medium warm it needs the enriches again for a moment. I am still learning what kind of porridge baby is willing to eat.
Kara

[ashleyf]

Thks guys, swapped over unit. No difference. Still impossible to start after 40 minutes ( maybe less) . Leave it alone for 20 mins and somewhere between 4-6 kicks to restart
Not great if I stall at lights.....

Loath to fiddle with timing, luckily have a great mechanic who will. Pickups are a half day replacement job, so will work thru other options.

It's a dream to ride. Looking forward to fixing it !

[81mhr900ss]

I would contact Sachse and see what they say about replacing the pickup circuit board only (and buying the same by itself). From pictures in the manual It looks like the PCB is attached to the bigger steel positioning ring by just 2 screws. If so, this is a really quick job. Setting up Sachse ignition is much easier in practice than from reading the manual!

[ashleyf]

Thks Rick, but replacement unit had same issue. Re timing, unsure why that would effect it only when starting while hot.

[900tlc]

Ashley,I would be tempted to change the coils,but first check the valve clearances.It only comes to mind with the tempreture issue,on starting hot.