Morini 1980 350 issues.

[tonup69]

Hello all. I am new to the board and just got my first Morini last week:



Kid not included.

So, I did some front end work since the front brake really wasn't stopping the bike and both fork seals were leaking. I had an extra rotor given to me in the deal and so I had that one skimmed and burnished. I also got new brake pads. Now I have a severe studder! I know that the machinist who dressed the rotor used the backing plate (where the rotor mounts to the wheel) as a guide for how level the rotor should be. Was that a mistake? Are these rotors at a slight offset or something?

Also, I noticed that before red-line in each gear when I am around half throttle the bike just doesn't go any faster. Wondering if this is a carb issue or should I look at something else? The bike runs fine a low RPM in each gear. Also, I did remove the carbs from the bike for a good cleaning with carb cleaner and comprssed air. The main jet is 115. Should it be bigger?

Any advice would be appreciated. I really like the bike when it is behaving. Hope to get these things worked out soon.

Cheers,

LTR
Memphis, TN

[unreal]

Welcome to the world that is Moto-Morini!
You'll find a lot of help here, also worth joining the Moto-Morini mailing list (morini@hazchem.smoke.com.au) which also has a few US subscribers.

Si

[EVguru]

You say you have a shudder. Can you feel pulsing through the lever, or does the front end just shake?

The brake disc should be centered in the caliper and BOTH friction surfaces must be normal with the mounting face. These Grimeca discs are apparently some fairly exotic steel (not cast Iron) and difficult to machine. Were they turned or ground?

A 115 main jet would be Sport jetting. You're bike is a long way from stock, so it's hard to guess what it might be. The only way to truly know is to read the cam marking and look at the pistons, but does the engine carry the 'S' on the right hand side just below the front barrel? An 8,500rpm red line would be a clue too. Sport engines (and to a much lesser degree Stradas) can suffer from a flat spot and need to go to the next atomiser (260BD for the Sport).

[tonup69]

You say you have a shudder. Can you feel pulsing through the lever, or does the front end just shake?

The brake disc should be centered in the caliper and BOTH friction surfaces must be normal with the mounting face. These Grimeca discs are apparently some fairly exotic steel (not cast Iron) and difficult to machine. Were they turned or ground?

It was a pulse through the lever. The rotor was turned by my local machinist, but I think he screwed up. It has a thick spot for sure where you can see heat markings from the pads. I put the old rotor back on (the one that came on the bike, not the spare I had cut). Now it doesn't brake very well, but it doesn't dive either. I am going to take the rotor back to the machine shop and have him fix the high spot. That should do it.

A 115 main jet would be Sport jetting. You're bike is a long way from stock, so it's hard to guess what it might be. The only way to truly know is to read the cam marking and look at the pistons, but does the engine carry the 'S' on the right hand side just below the front barrel? An 8,500rpm red line would be a clue too. Sport engines (and to a much lesser degree Stradas) can suffer from a flat spot and need to go to the next atomiser (260BD for the Sport).

After a day of riding yesterday it really feels more electrical than fuel, but you never know till you find the problem. I will look for the S. This flat spot, where is it? It feels like it is about 1/2 throttle - does that sound like the atomiser? I am used to playing with AMALs, not Delortos so I am not sure where to start. Thanks for the tips.

LTR

[tonup69]

one more thing - do these bikes typically have flat slide Dellorto's? I will get the model number off the carbs later today, but I did notice that they are not round slide carbs.

LTR

[EVguru]

one more thing - do these bikes typically have flat slide Dellorto's? I will get the model number off the carbs later today, but I did notice that they are not round slide carbs.

LTR

Oh, yes. VHB-25 on early bikes with solid inlet manfolds and VHBZ-25 on later bikes with rubber inlets. 500's rand 26mm carbs.

Round slides (38mm) were used on some US market Camels for emission reasons; they were available with an accellerator pump. They also found their way (28mm) on to 501 engines (Excalibur for example).

[tonup69]

Well, I am closer to figuring out the problem with my 3 1/2. I checked the timing with my stobe and it was not correct (retarded using the front plug lead). Then I checked the rear plug lead to see if they were "in phase". Well the rear plug is not firing above around 3000 RPM! Nothing! Sure enough, it was hard to hear, but I was running one cylinder for part of the day on Sunday. No wonder it has no power, eh?

Two questions:

1) I noticed the previous owner used B8ES plugs not B6EV as suggested on the tech section of this board (I think). Do you think that is really a problem? The B8ES plugs look perfect.

2) How do I test the transducer? It is a "green dot" model with a red pickup. I would just swap leads to be sure on a Triumph, but I think they fire at different times on this bike, right? Besides, the leads really are too far apart to swap. Who makes a replacement transducer?

Cheers,

LTR

[EVguru]

You'll have to physically swap the transducers to be sure. The plug leads just scew in and it's a good time to check their condition and consider replacing, likewise the plug caps (No resistor, or 1K, rather than 5K).

It could be a transducer, or it could be a pickup, or it could be a bad connection somewhere. This kind of fault can be be very frustrating to track down, but be methodical and try things one at a time. A fauly electronic tachometer can cause problems by the way.

The transducers are fairly common in type on all sorts of of machines, but the advance characteristics are not necessarily suitable. NLM can supply replacements, or a complete new pickup and igniton box. The circuit in the transducers is pretty simple and not difficult to make your own. The diagram is on my website and on the Dutch website.

[tonup69]

Good advice. So what can I do about the tach? Can I just unhook it and be done with that issue until I get around to sending it off for repair? I will try replacing the spark plug leads (copper core I assume). I already replaced the caps with NGK 1K resistor caps, but the funny running issue was in full swing before I even did that, so I don't suspect the resistors had any effect. Besides, one of the leads had a resistor cap already (two different kinds of caps on this bike ).

Do you now approximately how much the new transducers and/or the entire ignition would be? I am not too keen on becoming an electronics expert at this point, so I will just BUY a transducer even if they are easy to make from a stick of gum and some bailing wire.

Cheers,

LTR

[mgill]

I put one of these ignitions on mine, it works great.

http://www.elektronik-sachse.de/index_en.htm

Volker speaks english well, don't hesitate to call with questions.

As for spark plugs, I use BPR8-EIX and they work great, in my race bike.

Original spec was BPR6 (normal riding) or BPR7 (fast riding)

For street use I'd recommend the BPR7-EIX

Mathew

[jfh]

I see EV guru mentions faulty tachos can cause problems. I have to run mine disconnected because it cuts out whichever cylinder I plug it in to. What does this mean?

[EVguru]

I run BP7-ES plugs with good results. If your ignition isn't quite what it could be then you could try BP7-EV which is the wire (1mm) electrode equivilent. They'll spark with less voltage, but won't last or hold their gap as long.

The EIX suffix plugs use Iridium as the electrode material to extend the life with an even smaller electrode diameter. However they are quite expensive and are not available except as a resistor type. I wouldn't run these with the standard ignition and definitely not with resistor plug caps!

I see EV guru mentions faulty tachos can cause problems. I have to run mine disconnected because it cuts out whichever cylinder I plug it in to. What does this mean?

It means your tach is faulty.

[tonup69]

Well, yesterday I swapped the transducers so I could determine if it was the pick up or the coil. Guess what? Now the bike runs great! Must have been a loose or corroaded connection on the transducer. BTW, I am using some BPR7-EIX plugs now since I have them for another bike that uses an ET ignition (no battery or even capacitor). I found that the spark was much bluer and bigger using these plugs than the B8ES plugs that came with the bike. Not sure about long term, but it runs good right now.