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Hi All, so just logged back in for 1st time since 2010 its been a bit of a slog with my 350 but after fitting a modern sachse ignition kit i'm almost there with it, the only issue i still have is the tacho seem's faulty. ive heard that if the coil goes in them they are pretty much dead and buried ?? so just thought i would check in with you guys to confirm this is the case, if not is there anyone who could repair it for me .
thanks in advance, Andy.

andyp wrote: ↑27 Feb 2023 12:08 ive heard that if the coil goes in them they are pretty much dead and buried ?? so just thought i would check in with you guys to confirm this is the case, if not is there anyone who could repair it for me .
thanks in advance, Andy.

Yep Andy that's pretty much the case, my success rate of fixing coils is about 1 in 3, sometimes I get lucky and its a broken wire which whilst very fiddly is fixable but if its broken inside the coil its tough.
The coil itself could be removed, an new coil wound and fitted but its a former less coil glued onto a delicate armature which is part of the mechanism, totally uneconomic for me to do it commercially.
It seems that the symptom of the coil going faulty is that the tach under reads and this gets worse until it stops working.
Lively tachos are not always broken springs, or even mechanical issues, but often a circuit board fault. Totally dead ones; usually board fault.
I haven't seen one but I have heard that sometimes the plastic swells inside which stops it working.
I even had one that was supposedly fixed by a well known expert that had some connections that were not even soldered.
The open frame calibration potentiometer is often in need of a clean.

Circuit boards can be replaced, calibrated and new bezels fitted. This is tolerably interesting
Its difficult to get the bezels off and re-use them, so new bezel is needed.

whatever is done its a still an old instrument which isn't very accurate,
It would be better to update it to Arduino controller based stepper motor design
In any case a tacho on a Morini is largely an ornament.

Mark

thanks mark, forgot to mention i had the sachse ignition fitted also and this i believe can also cause issues with a working tacho ?? ive spoken to a couple of people today and on balance the conclusion is to forget it,,, the time and cost implications just dont make it worth the effort. hoping to enjoy this summer on it though

If you really feel a need to know how many rpm it is achieving you could lash on a cheap digital tach/hour meter. A bit of a delay so not to be relied on for 'red lining' but they do work.

Convert to cable tach. You need a nut, a trigger cover with 90 degree elbow, a cable and a cable tacho.

All available on eBay. The nut with the square hole may be more difficult to source.

72degrees wrote: ↑28 Feb 2023 19:02 If you really feel a need to know how many rpm it is achieving you could lash on a cheap digital tach/hour meter. A bit of a delay so not to be relied on for 'red lining' but they do work.

If its a standard strada i wouldn't worry about the redline

As MIke says a mech tacho is a reasonable option and way easier to fix. A little bit of tinkering and i think the face of the original tacho could be substituted so the mech tacho matches the speedo. TBH tacho not needed to enjoy the bike.

Mark

mbmm350s wrote: ↑01 Mar 2023 10:11

72degrees wrote: ↑28 Feb 2023 19:02 If you really feel a need to know how many rpm it is achieving you could lash on a cheap digital tach/hour meter. A bit of a delay so not to be relied on for 'red lining' but they do work.

If its a standard strada i wouldn't worry about the redline

As MIke says a mech tacho is a reasonable option and way easier to fix. A little bit of tinkering and i think the face of the original tacho could be substituted so the mech tacho matches the speedo. TBH tacho not needed to enjoy the bike.

Mark

I never worry about the red line on a 72 degree Morini and a tacho certainly is not required for enjoyment.

The road 375/2C has the mechanical tacho and head from a 250, so the red line is a tad generous and probably entirely theoretical in 6th

I fitted a £8 off Ebay one on the Forgotten Error hillclimber, mainly in the interests of checking gearing at hills with a decent straight but no speed trap.

It was then transferred on to the Gilera 175, to see if my seat of the pants judgment on rpm was lacking in mechanical sympathy.

The 1937 Sunbeam 250 also wore it for a while out of sheer curiosity. It confirmed what an incredibly low idle speed it was capable of on full ignition retard.

thanks all, some v knowledgeable people on this group, in all the years ive had this bike its been a crap starter, the sachse system seems to have sorted that issue, i can live without a rev counter no problem, do any of you fellas get to stafford ?

I’m glad you’re finding the forum useful. the club has a wealth of knowledge and some jolly nice people too.

Yes, we always have a stand at Stafford. Do drop by and say hello.

We also have quite a number of active sections who meet regularly where much wisdom is imparted over a coffee, beer or the like

I recently had my electronic tacho repaired by speedy cables ( www.speedycables.com) in Swansea. They replaced the cct board, calibrated and fitted a new bezel that I supplied. The process was not cheap and I am not convinced the tacho is working properly now. I found the bezels on e-bay, they are supposedly for smiths 80mm meters but fit perfectly.
The tacho does not move under 4000 rpm then does not climb above 1000 despite rising revs. All connections appear correct, 12v earth and a signal (not stable ) that changes with revs. further work is required and the engineer at speedy cables is available to chat as required. All work has stopped at present due to a close encounter with a very large dog with a dislike for morinis. I am pleased to report the dog was undamaged unlike my shattered left side tarozzi rearset and a bent exhaust.