Advice and Thoughts on Motoplat Ignition Replacement

[ksd124]

Hi all,

I recently bought a 1993 Sessantacinque 650GT.  They’re not common, I don’t think, and I’m not sure that they went to the US (I’m i Australia).  Anyway, it has the Motoplat ignition.  It hasn’t been running for 3-4 years.  I was told it was when it was parked up for brake issues - who knows if this is correct.

I don’t get a spark when cranking.  I’m reasonably certain that I have narrowed it down to the 2 x modules that govern the timing and cut the earth to the coils.  The following is how I have arrived at this - but would like to hear if anyone has alternate thoughts:

1. Coils are fine, as both will spark “blue-enough” when I either open the circuit or turn the key off.
2. I wondered whether volts to coils were to low when cranking, so I narrow plug gaps and connected a dedicated battery to the coils, but still not spark when cranking.
3. I think the pick-up / sender unit (ie the inductive unit located where the points are on previous models) is OK.  Both have 1k Ohm resistance between their output wires & earth.  Although I have no spec as to what this should be.
4. I removed the sender unit and simulated rotating it quicker with my fingers.  This produced a spark, although only on one module.  When I swapped the modules over, the alternate pick-up coil fired the “good” module, but neither would fire the “bad”.
My conclusion is that both modules are no longer “detecting” the trigger signal as they should.  The pick-up / sender should be pretty robust and looks in perfect condition.

A couple of questions for anyone with some experiences (direct or learnt from other):

- Does my analysis seem reasonable / logical.
- I’m considering an ignition module from Ignitech in Czech Republic.  I don’t think they include the sender unit - I’m hoping it doesn’t need one.  Does anyone have any experience with these?
- Does anyone have any alternative solutions they may have used?

Thanks for any input received.

Cheers,
Kelvin

[flangeman_70]

Hi Kelvin,

You can search for Newtronic (UK), Sachse/ZDG3 (German) as these can be made to work.
I have the ZDG3 on my SPIII and it works as it should with 9 different curves.
My colleague has the Ignitech on his 850T, again it works but you need to map your own curve.

There was an Aussie guy making something similar to the Newtronic but I can't find it anymore.

Another option is the unit by Cliff Jefferies in Oz. The standalone ignition unit is fairly new by him but if it is as good as the MyECU (I have it on my Centauro) then all is good.

Good luck!

Adam

Adam.

[ksd124]

Thanks Adam.  I’ll look a few of these up.  Ignitech do a specific model (not programmable) for a small block 750 NTX.  My thoughts are that if the initial advance and maximum advance are similar for both this and the 650 I have, then hopefully it will do the job.  Of course if the Ignitech model isn’t any cheaper than the programmable units (or units with multiple curves) then I may as well go with one of these.

Thanks again,
Kelvin 

[Antietam Classic Cycle]

I think this might be another alternative: http://www.c5ignitions.com/motorcycle-ignitions.html
Scroll about 2/3rds the way down to the MG-NTX system.

[redrider90]

The motoplat  modules on the big blocks were notorious for failures like you are detailing in your post.


This place carries quite a bit of custom made  aftermarket motoplat products but a quite a price.
http://www.carmo.nl/index.php?main_page=index&cPath=4290_22_131&zenid=f5fsjskjfur88bugf12cpeva92

There is this place http://www.gawa-guzzi.de/elektrical.html

[ksd124]

Thanks again folks. I wasn't aware that C5 did one for the small block.  Is the general consensus that they are reliable?
Looks like I have a few options. This bike will be a bit of a run about, so will go with something reasonably economic. Chrs


Sent from my iPhone using Tapatalk

[redrider90]

I forgot last night when I posted to mention Triple Jim who makes CDI units.  He recently made a CDI unit for his Mille that runs on points but is capable of making CDI units for probably any system. I am not sure he is ready or has the knowledge to build one for your bike but he builds quality products. I know he does not like to use the forum to toot his horn so I am going to do it for him.
His profile is here  http://wildguzzi.com/forum/index.php?action=profile;u=12709
and his company is here.       http://www.lakeserv.net/kaw/

[ksd124]

Thanks RedRider90.  I’ve seen Triple Jim very active on here.  I’ll look up his Co. now.  Cheers, Kelvin

[Triple Jim]

Kelvin,  The only CDI unit I've made for Guzzis so far is one that is triggered from points, and it's on my Mille.  The neat feature is that if something goes wrong with it, I can unplug it, return the system to stock with no tools, and keep riding.  I'll probably work on a system triggered by the Motoplat distributor at some point, but I haven't done that yet.

[ksd124]

Cheers Jim.