New to me Strada

[Papa Lazarou]

James,

Glad you enjoyed riding it so far, apart form the wooden brake!

Flywheel magnetising was checked by NLM and found to be good. It holds 2 Kg lump hammer which was my basic rule of thumb test and then checked by NLM. If you check back on my threads Paul Compton advised changes perhaps required for carbs in relation to pilot jetting and needles although I think he said don't move the needles. I thought it was running very rich initially and as I said it could probably do with some fine carb tuning to resolve the flat spot that you mention.

The mudguard stays are in one of the boxes however as explained one was missing and requires a new bracket to mount at the rear of F mudguard.

Hope these comments help. Although you are already finding out that the collective on this forum is very knowledgable and I'm sure many good solutions will be forthcoming.

Have fun and don't be over exuberant reliving your teenage years. Your a long time dead.

Thanks Archie and thanks all. Don't be too worried about the exuberance-been riding since 1972. I'll play with jet sizes after fixing the brake.

[Papa Lazarou]

Smaller bore master cylinder fitted, as per the earlier suggestion by Bison. I'll try it out later.

I have a working front brake! Easy fix.

Now to find out why the engine goes flat at higher revs. Ignition...or carbs?

[MickeyMoto]

What size main jet are you running?

I think standard was 112 with an open airbox.

I had the same problem resolved by larger jets.

[Papa Lazarou]

What size main jet are you running?

I think standard was 112 with an open airbox.

I had the same problem resolved by larger jets.

Thanks. Only had it a few days and I'm thinking of buying two complete sets of jets and atomisers. So, right now, no idea what size mains are in t he carbs. I'll pull both when the weather picks up (have to work on the street).

According to the Dutch site (useful) to me) these are the jet sizes:


350 GT - 1973
VHB 25BS
idle: 50
main: 112
atomiser: 260K
choke: 50

I could happily fit Mikunis or PHBH carbs.

Mickey-what size mains are you using?

[MickeyMoto]

Not helpful, I'm afraid. I have a 501 with 28mm carbs! I would start with the jets as you have a 'sport' exhaust!

[Papa Lazarou]

Not helpful, I'm afraid. I have a 501 with 28mm carbs! I would start with the jets as you have a 'sport' exhaust!

apparently not a sport exhaust...ho hum.

[George 350]

Hi.
As Paul says, you have "standard" silencers, albeit they look like the Brituro copies to me. (I have the same on my bikes añd yes they are loud). As regards the jetting, I would start with just changing the pilot jets to 42 or43's and work from there. The 260K atomiser is no longer available. Penman Joe recently went through a whole bunch of carb setting issues with a K2 so hunt for that thread for ideas.
Regards, George.

[penman]

Hi,
Just to follow up on George's post, I think the original setup is just a bit too rich for modern fuel and I fully support the move to a 42 pilot jet. This will give you much better off-idle response, especially when hot. If you search for "atomisers" on this forum, you should find a little table I made up of atomiser types. Not all are still available, however if you have a Dremel and a soldering iron, it's not difficult to convert one atomiser type to another. I think I ended up with 260CM, which eliminated a mid-range flat spot. If my memory serves, the "K" atomiser is a pretty lean one as well, so it may be fine. Sorry, I'm away from home this week, so I don't have the info to hand. Good luck with it, it's definitely worth a bit of fiddling!

Joe.

[Papa Lazarou]

thanks George and Penman. I've just received 50 idle jets...I'll order some 42s. The silencers do seem to be standard as you say-one is a Lanfranconi, the other a pattern.

The Dutch forum seems to think the bike has a transducer problem.

I quote:

"When I first had my 1973 Strada (GT) it had the same problem. After some good advice it was quickly sorted.

There are 2 parts to check:

1) the ignition coil in the alternator. From the engine housing a black wire goes to the fusebox. In it are 4 coloured wires:
two yellow, one red, one green. Take off the green wire from the fusebox and measure the electrical restistance (in Ohm) agains mass (the frame). You should have a reading of anything between 160 and 300 Ohm. Between 160-180 Ohm the bike will probably start badly. According to the factory workshop manual the ideal resistance is 300 Ohm. I have measured 5 independent coils and they all measured 220 Ohm. My own bike with a 220 Ohm coil starts first kick.

2) most likely one or both transducers (the coils under the fueltank) are shot. They can be "half broken". This means the bike will start normally, will run normally, up to the critical point of 5,000 or 6,000 rpm. when the advance has to come in. Inside the transducers there is an HT coil. More windings of this coil are probably short-cut and this results in the problems you describe.

Fortunately you can get new transducers these days. On the early bikes they are black/square in combination with a red pickup. On later bikes the pickup is black and the transducers are grey.
On the website http://www.motomoriniclub.nl/tech.html you can read about the transducers and which types you can get as a replacement.
Mind you, after installing new transducers, you should use the strobe to set the timing correctly.

Finally, also make sure the blue (white?) wire from the transducers to mass/frame is allright: not broken and the connector properly to mass.

According to the German Morini community, the blue transducers are a good alternative for black transducers. On my 2nd Morini I have got grey transducers. I bought a new set from Nuovaray in Italy.
This is the blue one: http://www.motelek.net/andere/cdi/ducat ... 12-cdi.png for Vespa and Lambretta."

[penman]

You are starting to open a can of worms here! First thing to remember is that ignition and fuelling issues can produce similar symptoms so at this stage, I would suggest some more diagnostics before starting to change things. It's worth having a look at your spark on both plugs and call on the old rhyme "white is right, blue will do, but red is dead" this refers to the colour of the spark in free air and it's not a bad starting point. If you have a red or yellw spark, it might suggest an ignition problem, especially if the other spark is nice and bright. Next check the ignition advance with a strobe light - again, you need to check it on both plugs. Bright sparks and correct advance and I'd turn my attention to the carbs. By the way, the ignition winding on the stator is well known for failure after all these years, especially if the bike has been unused for a lengthy period, and that's what I would suspect if both sparks are weak. Moisture ingress into the coil can lower the resistance of the insulating varnish, causing leakage or even short-circuit turns. A DC resistance check is a good indicator and as you've heard, you are looking for 200 ohms at least, 220 would be better. But, a nice bright, white spark tells you that this is working pretty well - it's possible it may start to fail at high rpm, but there are other things to check first.

If you do suspect a problem with transducers or pickup, a loan of a known good set is really helpful. I was lucky to be able to borrow a set from someone who lived fairly nearby and it allowed me to eliminate the whole ignition system as a problem area in one go.

Once again, good luck!

Joe.

[Papa Lazarou]

Thanks Joe

A complete overhaul of carbs and ignition system is on the cards. I've never had a Morini before but I've restored a few old bikes.

[Bison]

Mornin',
I had very similar problems with my Orange Sport when I got it, started beautifully, revved when not under load, sounded great and idled nicely. I rigged a strobe and had a look at the flywheel, it wasn't advancing the ignition, at any revs, new transducers (blue, vespa) and it went like the wind!.
Have you had a chance to try the front brake on the road yet?
Alan.

[fatnfast]

Hi Papa,
I thought you had just bought this as a restored bike, and the advert on here stated the carbs had been ultrasonically cleaned? Is it worth a pm to the seller to see if he can shed any light on this? I assume he had it all running sweetly prior to sale?

[Papa Lazarou]

Hi Papa,
I thought you had just bought this as a restored bike, and the advert on here stated the carbs had been ultrasonically cleaned? Is it worth a pm to the seller to see if he can shed any light on this? I assume he had it all running sweetly prior to sale?

I think I'm going to have to. He did say he had never taken it out, so this problem would not have shown up. He did say it started first or second kick.

Today, I fitted new NLM transducers, checked the stator resistance (285), checked the flywheel-good magnetism. Now, intermittent spark and will not start.

I'll double check I've wired up the NLM stuff correctly tomorrow. Enough for today.

[fatnfast]

It must be so frustrating, but there are good knowledgeable people on here that hopefully will help.
I'm guessing the bike must have to least been ridden to the MOT station, so any problems should have been apparent then?