Ignition timing issues

250 2c- the Wee-WeeVees
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BarryCambs
Posts: 20
Joined: 23 Sep 2019 12:49
Location: Cambridge

Ignition timing issues

Post by BarryCambs »

I've been using the morini for a while but I noticed the idle was becoming a bit unreliable, then one of the plastic choke levers snapped off so I thought it might be time for a carb ovehaul.

I got couple of genuine gasket kits from Eurocarbs and 2 new choke plungers and put the whole lot through the ultrasonic cleaner. I set it up and it ran beutifully. Slight hesitation rolling on and off the throttle had disapeared as a bonus. I then decided ii'd pop over a mates and give it a final tune on the carb balancer, but it didn't go well and I suspect one of the plungers was sticking as when I got home and checked, one slide was opening about 3mm before the other. I've reset everything manualy and it starts and runs well, but the tick over's not great. It seems to be missing on the front cylinder. Carb rubbers are nice and soft, but the mixture screws can be moved a few turns without much effect.

I wanted to check the ignition timing before going any further, as I don't rememebr doing this when I recommissioned it in a fog of sleep deprevation. I marked the ANT line with white paint and fired it up. At it's current quite fast idle, the line and crancase mark lined up with the strobe, but from the manual, it says they should align at 6,000 rpm, which I assume is full advance.

If I increase the revs, it starts to advance, (as a jump, rather than smoothly), but at about 6,000 rpm it jumps back and the marks line up again. When it does advance, it's only by a few degrees.

Could this point to the ignition module failing, or have I missed something? I'm not minded to fiddle with the carbs anymore, until I am convinced the ignition is right. I always remember the workshop manager saying "rememebr 90% of carburation problems are electrical" all the time. I'm not sure why, as I was doing an apprentiship on diesels, but there you are

Barry
BarryCambs
Posts: 20
Joined: 23 Sep 2019 12:49
Location: Cambridge

Re: Ignition timing issues

Post by BarryCambs »

I've probably answered my own question. I just check the rear cylinder and while its a bit difficult to see anything even in the shade today, that does act as exected. Thinking about it, the front one just seems to be stuck on full advance (with occasional flickering) so presumably something has gone short/open circuit in the electronics.

I'll replace with a matched pair, but a quick look and it seems they are not easy to find. Mdina don't seem to have them for sure. It seems some people have replaced them with Piagio boxes??

Any help much appreciated!

Barry
mbmm350s
Posts: 664
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Ignition timing issues

Post by mbmm350s »

Hi Barry,

The fault you describe can also be a fault with the pickup , so please check whether the fault follows the transducer (CDI) box if you swap them over, or whether it stays on the front cylinder. If it follows the transducer then I would advise to buy new ones in a pair, because any second hand ones will be 30 years old.

The standard equipment on the 250 2C is a red pickup with black resin and two flat black transducers with a green sticky dot, the part number is 323921
So many times we try to debug ignition problems only to find that the wrong parts are there!

The correct new replacements for the transducers and the pickup too if needed can be obtained from Alex Luzzi in Siena.
(alexluzzi@gmail.com) you can write in English.
We fitted these to the club strada.

The pickup is referred to a "red" for the 250 2C, the CDI boxes are the same as 350. Alex will supply upgraded boxes with stronger spark than compared to the original, these are referred to as "bulged"

The Piaggio Scooter CDIs from Vespa PX125 and similar can be used also, but these will need the pickup to be retimed due to the difference in the full advance of the scooter. Both our 250s have later "scooter" transducers.
There are comments on this in various posts on the forum

Depending on the particular transducer and because the mounting of the transducers on the 250 is a bit tight you may need to make a little bracket or adjust some holes.

Also please check out the very helpful pages on the Netherlands Moto Morini site, this explains all about the pickups and transducers.
https://www.motomoriniclub.nl/tech.html

Timing should be done at 6000 rpm, which will be near to full advance, at the moment it appears that your setting is over advanced at idle.

Hope that helps
Mark
BarryCambs
Posts: 20
Joined: 23 Sep 2019 12:49
Location: Cambridge

Re: Ignition timing issues

Post by BarryCambs »

Hi Mark

Thanks for the advice! I'd actually contacted Alex yesterday and he's put a couple of transducers in the post for me. He did ask me to check the pick up colour first (black) , so at least everything will be matched. The bike's currently fitted with the red transducers shown on the Dutch site with a cross through them and 'do not use'. I was pleasently suprised at the cost, given he's had these manufactured and (£150 including carriage) so it didn't think it was worth going with the Piagio ones. He tells me he has plenty of other parts for the 250, so I guess they were more popular in Italy?

I did check the timing at 6,000 rpm which is when I realised the marks remained lined up at any speed. It did wonder about swapping the transducer to the other cylinder, but I assumed the pick up would either work or not. It might give weak or intermittent spark, but shouldn't affect the timing?? The coil is still giving a nice spark (probably better than the rear), it is just the timing that's wrong and as I said, it's just stuck on full advance.

I decided not to mess about and replace them anyway. Bitter experience tell me coils seem to have a shelf life even if not used and while they will normally start and run beautifuly when you recomiision something, the first time they get really hot they'll start to break down. While the bike was running when I got it, the eldely owner said it had only ever been used for a quick potter round for the last few years and hadn't been used at all recently. It was running ok until I rode it on a 100 mile round trip including coming back from Harlow to Cambridge on the M11, which was probably the hottest it's got for 20 years!

I'm hoping there's a chance they will be here for the weekend as Im supposed to be going out on a fish and chip run to the Norfolk Coast with some friends. Bit of a long story, but I didn't actually want the Morini, but due to a break down in communication, a friend bought it for me and as the Guzzi was off the road, I thought I might as well ride it while I wondered what to do with it. I went out on a ride out with a local group and half way through the day, I realsied it was one of the nicest bikes I'd ridden and I got back home completely in love. The only way I'd part with it now is maybe for a 350, as with the best will in the world, it's not the best high speed motorway machine.

I've booked for the Rally in September :)

Thanks again, Barry
mbmm350s
Posts: 664
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Ignition timing issues

Post by mbmm350s »

Hi Barry,

Hope it will be sorted soon, you are right about the coils all windings breakdown over time, and the spark will be weak and even retard.

I didn't think the black pick up was compatible with the red transducers, and the advance then retard problem is the problem you get when the diode is missing or faulty.

The diode was in the red pickup, but was removed in around 83 from the black pickup and is in the grey bulged transducer. This was to make the pickup more reliable and gives a little more advance in higher rpm.

The correct black pickup should have a sticker that gives warning about only to be used with grey transducers.
There were some other pattern black pickups, some are good but there were a few rogues that are unusable.

Alex will send the correct parts.

Cheers

Mark
BarryCambs
Posts: 20
Joined: 23 Sep 2019 12:49
Location: Cambridge

Re: Ignition timing issues

Post by BarryCambs »

These are the photo's I sent to Alex.
IMG_20230612_081932157.png
IMG_20230612_081932157.png (346.65 KiB) Viewed 1349 times
IMG_20230612_082104015.png
IMG_20230612_082104015.png (301.95 KiB) Viewed 1349 times
Until I looked at the potos, I'd not really nticed the chock block is actualy holding a componant, rahter than just joining wires. It's not got any markings, but I suspect it's a diode, which would make sense from what you say. I'm not sure why there's only one, unless the other one is hidden behind the transducer. The bike is 1980, so if you say the diode was remived from the pick up in 1983, I guess this is a later pickup that's been fitted.

I'll have a good look over the rest of the loom when I get the transducers and go through the earths.. There's obviously been some modification to the wiring around the transducers, but mercifully, the rest of the bike is in original condition. My only other issue is the seat. It seems to have lost it's hump and I suspect someone cut it off to fit the rather nasty universal seat cover. I got excited when I saw Mdina had the cover listed, until I saw it was out of stock.

Luckily, I found another 250 owner lives about 4 miles away, so I'm hoping to meet up with him to check I at least have the right seat pan. If that's ok, I'll take plenty of photos and measurements so I can take the bike to a vehicle upholstery guy a friend used for a similar project.

Barry
mbmm350s
Posts: 664
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Ignition timing issues

Post by mbmm350s »

Hi Barry,

Its hard to be sure, but that does look like a genuine black pickup.

The device in the choc block is another diode, this is in the green lead to the switch and is used to prevent a fault in the switch from getting 12V onto the ignition circuit, if 12V gets onto the green wire it kills the transducers if you try to start the bike. It is shown in the wiring diagram
PM me and I can email you the user manual.

I can see how tight the bulged transducers are on the 250 mounting, I mentioned that previously.

I have a 250 declared as 1980, but its 1983 from its frame number, never totally believe date unless you have documents!
All through production of 250s there were two seats available,
there was a touring seat and a more sporty seat with a small hump.
The sporty variant also had the ACE type adjustable bars and sometimes the aluminium kickstart.
But you could order the higher bars, so you could have high bars and sport seat if wanted.
Unfortunately with respect to the cover, Selle Nisa don't seem to show it any more.
http://nisasrl.it/en/category-product/s ... morini-en/

Before the 250 upgrade in 82, the rocker covers were painted black, after this they were polished, the upgrade model has a different tank and small tail fairing, and normally a square headlight.
basic pictures here:
http://www.motomoriniclub.com/lemoto/12 ... radali.php
The 79 250 never actually had the half and half scheme of the brochure, and was delivered with plain red (or brown) with pin striping.
cheers
Mark
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chinnock3963
Posts: 16
Joined: 19 Oct 2023 10:43
Location: somerset

Re: Ignition timing issues

Post by chinnock3963 »

BarryCambs wrote: 11 Jun 2023 12:25 I've probably answered my own question. I just check the rear cylinder and while its a bit difficult to see anything even in the shade today, that does act as exected. Thinking about it, the front one just seems to be stuck on full advance (with occasional flickering) so presumably something has gone short/open circuit in the electronics.

I'll replace with a matched pair, but a quick look and it seems they are not easy to find. Mdina don't seem to have them for sure. It seems some people have replaced them with Piagio boxes??

Any help much appreciated!

Barry
User avatar
chinnock3963
Posts: 16
Joined: 19 Oct 2023 10:43
Location: somerset

Re: Ignition timing issues

Post by chinnock3963 »

Hi Barry . I noticed that you sent for tranducer's from Italy, did you finally get your items or refund as I'm thinking along your lines for replacing my ignition. But don't want to lose my hard earned cash in not receiving either ., if not where did you get your parts ...Dave
mbmm350s
Posts: 664
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Ignition timing issues

Post by mbmm350s »

chinnock3963 wrote: 05 Feb 2024 11:56 Hi Barry . I noticed that you sent for tranducer's from Italy, did you finally get your items or refund as I'm thinking along your lines for replacing my ignition. But don't want to lose my hard earned cash in not receiving either ., if not where did you get your parts ...Dave
Dave,
You should have no problem to order from Alex Luzzi, we have ordered from him new CDI and compatible pick up as have many others.
Mark
BarryCambs
Posts: 20
Joined: 23 Sep 2019 12:49
Location: Cambridge

Re: Ignition timing issues

Post by BarryCambs »

Hi Dave. I did get transducers from Alex some time ago and they did cure my timing issues.

Unfortunately, it then transpired I had a dodgy pickup on the front cylinder as well. I ordered a pickup months ago and Alex finally got back to me this week to say the last one in stock had damaged wiring and while he returned it to the place they are made, the factory is now closed due to illness and there is no telling when, or if, they will be available again. He's refunding my money. I've looked everywhere, but pickups seem to be completely unavailable. He did say he has some of his own design which he's trying to speed up bringing to market, as a result of the supplier potentially being permanently gone.

I think I'm going to cut my losses, convert to 12 volts and fit a SWF ignition rather than hope some pickups appear before the summer riding season.
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chinnock3963
Posts: 16
Joined: 19 Oct 2023 10:43
Location: somerset

Re: Ignition timing issues

Post by chinnock3963 »

Many Thanks Barry for your reply, yes I was told couldn't supply a replacement red pick up so im undecided where to go from here, or what other
Options and cost etc..many thanks again for your input ,
Dave...
BarryCambs
Posts: 20
Joined: 23 Sep 2019 12:49
Location: Cambridge

Re: Ignition timing issues

Post by BarryCambs »

I should have the SWF setup by next week and I'll do a proper report once I've fitted it. I like the fact it's a complete kit with coils etc and everything is on the pickup board, so no extra control box to mount and wire. It's also considerably cheaper than the Sachse kit, when you factor in the cost of coils. I'm just sorting out the bits for the 12v conversion.

In terms of relative cost, the SWF system is slightly cheaper than replacing the transducers and pickup. I needed a battery, rectifier/regulator, flasher unit and bulbs for the 12v conversion, but I would have probably done that anyway, as riding with a 6v headlamp and middle aged man eyesight is a truly terrifying experience!
morini_tom
Posts: 905
Joined: 05 May 2006 13:47
Location: Northampton

Re: Ignition timing issues

Post by morini_tom »

BarryCambs wrote: 11 Feb 2024 19:55
I think I'm going to cut my losses, convert to 12 volts and fit a SWF ignition rather than hope some pickups appear before the summer riding season.
Don’t give up on the original system! The good news is that pickups can be rebuilt.

Contact George Lane in the club. I’m sure he can help with a rebuild of your pickup.
BarryCambs
Posts: 20
Joined: 23 Sep 2019 12:49
Location: Cambridge

Re: Ignition timing issues

Post by BarryCambs »

Hi Tom
I didn't realise someone was doing repairs. Unfortunately, I've already ordered the SWF system and the Morini ones are built to order. Anne at SWF said it would be done this weekend, so it's too late to cancel. Having waited 5 months to find I couldn't get a pickup, I was desperate to sort it one way or another, before spring. I did wonder about doing some surgery to see if it was obvious what the Hall sensors were, but I didn't want any more delay. I'll keep the original wiring etc on the bike, so I can go back to the original system if needs be.
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