De-Restricting a Minarelli V1?

I was wondering if anyone has any guides or info on how to de-restrict a Minarelli (If you even can). For reference, Its on a Motomarina Sebring

Re: De-Restricting a Minarelli V1?

Check the carb size. It is probably a Dellorto 12-10.

If that is the case it probably is not restricted but rather it is going the best it can with the stock set-up.

What muffler are you running?

Have you checked for carbon build-up in the discharge?

Have you checked the timing?

Have you tried putting in the thinnest head gasket you can find?

Otherwise, probably the easiest thing you can do is find a pipe to put on it. A two piece Biturbo will fit.

Re: De-Restricting a Minarelli V1?

Perfekt Timing Angel /

What re you trying to get out of it? Top speed, or low end?

They aren't all that restricted. Sebrings are pretty chunky bikes, with chunky gearing to boot. If you want pickup, try changing the sprockets. New rings will help the compression, as well as Silverfox's suggestions.

I've never heard of a DellOrto 14/10, did you mean 14/12? You could try a bigger carb ie 15/15 or 16/16. An even beefier carb/intake combo in conjunction with a kit would make it quick.

A pipe makes a big difference, but Minarelli pipes are pretty rare at the moment. I've heard Puch pipes will work with some fabrication.

Re: De-Restricting a Minarelli V1?

puch pipes for sure or angelo for leo vinci v1 pipes.

Re: De-Restricting a Minarelli V1?

Matt Scout The Scouting Dcon /

what is Angelo's contact info? I heard the leo vinci pipes are good for low end omph, looking to add some of that.

Re: De-Restricting a Minarelli V1?

I have a 14/12. I'm probably going to go with the two-piece biturbo and a new Air filter to start.

Re: De-Restricting a Minarelli V1?

do a full tuneup first! new points and condensor, set the points. gap the plug a little over spec, clean and rebuild the carb. from there see how it is. shitty spark will really make your bike feel slow. just fixing that can be a real kick in the pants buddy! a good ignition system can run a plug with a little more gap, that'll light off the mix a little more completely and can gain you just a little more lowend.

from there make sure the plug wire is in good shape, boot is in good shape, the connector from the plug to wire is secure, the plug is the correct one.

on the carb, take it apart completely and soak it all in cleaner, blow all parts and passages with high pressure air. install new bowl seal, new needle, check that it seats against the needle seat well and that the float moves smoothly and does indeed float!

measure your intake port, theres a 12mm version and a 14mm version iirc, i've seen both cylinders and have one of each. other than that, both are identical. you can bore that 12 to a 14 no problems, just be sure to smooth it all out inside the intake windoaw so its smooth transitions!

you can bore the carb to 14mm all the way through, use a 9/16th drill bit, its 14.2 mm which is close enough for this.

with the exhaust, you can "derestrict it" by running a very long 3/8th" bit up the stinger and drilling the first baffle you hit. it should run through the stinger and then through a hole, then hit a baffle. drill a hole in that baffle. it'll change the tone of the pipe a little but mostly it will raise your topspeed by a few mph.

the V1 is primarily, when it has the 14mm intake port, restricted by its exhaust. adding that hole will take away some of that, but its not a substitute for a good chambered pipe.

Re: De-Restricting a Minarelli V1?


Re: De-Restricting a Minarelli V1?

Make sure you check your jetting since you going play with the in and out of the motor.

Re: De-Restricting a Minarelli V1?

My deristricting story:

Cimatti City Bike 20MPH

Minarelli V1

Tune up first

timing was retarded

just the timing points and plug really woke up tis engine.

14.9 carb, yeah. 9mm on the filter side. bored to 12.5

custom fabricated a intake out of .75"O.D. thin wall alum tube

the intake port window was tiny, like no bigger than my pinky nail. I left the highth alone and almost doubled it in width.

I lapped the top of the jug till about half of the bevel was gone.

Now, with a stock pipe, but not the old pancake muffler, it does a respectable 27mph

Re: De-Restricting a Minarelli V1?

Plus this:

Even when running the stock jet with the opened up carb, opened up intake, no airbox, no filter mesh, it was still rich. I soldered the jet and went down a size. Now the plugs come out dark brown but not black like before,

Re: De-Restricting a Minarelli V1?

The port window is the place to be with making it fast.

Make the window wide as possible. It really changes the powerband to stay in longer and more tonque.

Re: De-Restricting a Minarelli V1?

Sorry I am abit new to this whole porting thing, what do you mean by "port window"

Re: De-Restricting a Minarelli V1?

research 2 stroke engines. Start reading thats how I learned it all. No one showed me. Good luck :) Its a easy thing to do.

You will need a manual and need to make tools or buy them search ebay and google. There a manual on the mra site.

Re: De-Restricting a Minarelli V1?

Take the intake off of the cylinder and look thru the hole. The port window is that sqaure-ish shape in the wall of the cylinder. Mine was very narrow, using a carbide cutting tool I slowly and carefully opened the intake port to match my intake manifold and down the port at the cylinder wall i widened that shape.

Re: De-Restricting a Minarelli V1?


Re: De-Restricting a Minarelli V1?

whats the best pipe for this guy, and where can I get one????

Re: De-Restricting a Minarelli V1?

i have a yankee peddler with a minarelli v1 in it. knowing that pipes are scarce (there is that leo vinci one), i just used a 2 piece bi-turbo my buddy had laying around. its for a tomo, but with some small welds and a little bracket, this thing fits on it like a charm. very sturdy. pipes dont do too much without a new carb/intake or better yet a bore kit. so if all else fails, be crafty with a bi-turbo because theyll fit pretty much any bike.

Re: De-Restricting a Minarelli V1?

I'd like to de-restrict my '75 Cimatti City Bike's long stock exhaust. I've read several posts (Bitter, you out there?) that say I can take a long 3/8" bit and drill a hole, via the stinger, through the baffle to let her breathe a little bit. I've already drilled my DO 14/9 to 14/14 and opened up the intake manifold to match. No porting (yet) but have a 75cc Polini on the way and will look for a bigger carb at that point.

Anyway, on my stock exhaust, the stinger opening is less than 3/16" (7mm) wide. Do I drill the stinger out to 3/8" or do I remove it first? If I remove it and look in, there are two holes in the first plate I come to. Do I guide the bit through one of these holes, keep going, and drill the next baffle I get to? Could I just run with the stinger out altogether? Do I drill a third hole in this plate?

Maybe these pictures will help explain my current set up. Can somebody clue me in to the "hole mod procedure?" Thanks!

Re: De-Restricting a Minarelli V1?

Luke “Funkenet” Hosfield /

Bump. How do you derestrict the stocker v1 pipe?

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