Tune up a morini franco mo1 engine

I have an old negrini with a morini franco mo1 engine and a 14/12 dellorto sha carb. Was wondering if anyone could give me some advice on tuning it up a bit? Kits are hard to find for this engine I think. I'm guessing I get about 30 mph right now, though I haven't 'officially' clocked my speed. It'd be great to get like 45mph or more, but I don't know if that's realistic without a kit...

I've heard of buying new exhaust, performance air filter, boring out carb to be 14/14, larger jetting size (honestly have no idea what jetting even is...), and etc.

How much of this would I have to do to see a significant difference?

Re: Tune up a morini franco mo1 engine

just bore the carb, put lots of holes in the airbox, upjet and put a pipe on and you can get to mid to high 30's.

Re: Tune up a morini franco mo1 engine

What # Jet size should I get? If I only do some of these things will I see some improvement or does it all have to be done at once?

Re: Tune up a morini franco mo1 engine

mid 50's jet.

Re: Tune up a morini franco mo1 engine

OK. so say I put a size 55 jet on there. How much should I drill out the air box so that the fuel/air mix is still good? Is it just an experiement type thing or are there general "DO"s and "DON'T"s

Re: Tune up a morini franco mo1 engine


do buy a 14 mm delorto should be a 14/12

with a 72-74 jet

keep silver piece in carb(filter)

take plugs out of stock airbox-do not drill-

do not bore the carb,youll mess it up...maybe

drill tiny hole where kickstand rests against tail pipe-in pipe

there you go de restricted!-start small hole then experiment see how it goes i have a pacer with the m1 new valve engine

goes 40 plus all stock


Re: Tune up a morini franco mo1 engine

Oh wow thanks man! So you think 72-74 jet?? Man I already ordered a 55 and a 60 to experiement with... will those be way too small or what? Thanks for the drilling info too! I've heard about drilling in the exhaust but couldnt find any info on where exactly to do it and how much... I will definitely try this. And yeah I was kinda worried about boring out my carb so I'm glad you mentioned to just not do it at all :)

Re: Tune up a morini franco mo1 engine

Bennington Purcell /

I have a malaguti Commuter 77 and have been working on tweaking her up to speed.

I drilled two little holes in the exhaust and have upjetted to 56. Seems to be running great, my plug shops have been healthy looking.

I seem to be going about 32mph top speed (GPS)

Which is great!

So yeah, do these things and you will get some nicer speed

Re: Tune up a morini franco mo1 engine

Exactly where and how large are these holes you're putting in the exhaust? I've got an MO2, so I assume that these mods will work exactly the same, since the trans gearing wont affect the top speed, just it's acceleration.

Re: Tune up a morini franco mo1 engine

I'm watching this thread with interest. Running the same engine and have been doing some research too. My bes gain has been from opening up the intake manifold. Had to do some major dremmel work to enlarge two small holes into one large rectangle to increase airflow.

Running a SHA 14-9 (bored out a little to a 10.5 approx) and I also have a 14-12 SHA, but I actually slow down with that one. I think I need to upjet (45 and 54 run about the same) I have a set of tiny drills......

Re: Tune up a morini franco mo1 engine

I also have a SHA 14-9 and I'm wondering if these mods will work for me as well.

I would think: Take plugs out of airbox - Drill exhaust - Upjet a bit but not as much as for the 14-12

Do some plug chops and check it out.

Anyone think this will work.

Re: Tune up a morini franco mo1 engine

also.. throw the 9mm carbs to the side for parts..

put a 12mm on there... port match the exhaust....

The best thing is to get a .. gila/polini reedvalve conversion kit.

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