Motori Minarelli S.p.A was an Italian company founded in the 1950s that produced small engines. Many Minarelli engine parts can be interchanged with Morini Franco Motori engine parts due to the extreme similarities in design and construction.
Mopeds with Minarelli Engines
- Fantic Motor
- General 5-Star
- Gloria Intramotor
- Moto Bimm
- Moto Gori
- Yankee Peddler
Types: Some varieties of the Minarelli engines are the typical, and equally awesome, V-1 port-inducted engine, but also came as: The V-1L cased-inducted reed valve engine; The V-1LKS case-inducted reed valve kick-start engine; V-1HS Electric Start; C-2, C-3, and V-2, which are variated engines. The latter are more sought after for their elusive and rare existence.
Restrictions: Some Minarelli engines came with either a 20, 25, and 30 mph cylinder. This is often discovered by measuring the cylinder bore, though other restrictions included a smaller, more constrictive 9mm intake port and intake manifold. Usually they are seen with a forward-facing or bent-style 12mm intakes. Some bore sizes for 20 mph versions are: 38.0mm, 38.2mm, 38.4mm, 38.6mm. Others include: 38.8mm, 39.0mm, 39.2mm, 39.4mm, 39.6mm, 39.8mm, for 25/30 mph versions.
20 mph versions may also have 9-Teeth (TEEF!) front sprockets, while 25 mph versions may have 10T, and the 30 mph might have 11T. Rarely, they may even have 12T or 13T. Non-variated bikes may have anywhere from 38-45+ Teeth on the rear sprocket, which could restrict certain rpm ranges as well.
Also, there appears to be many versions of exhaust systems including, but not limited to, a typical, linear pipe, a 'pancake' exhaust that mounts seamlessly on the underside of the engine (most engines have a small bolt on the left hand, bottom side of the engine for this exhaust), and a beefier, Bi-turbo-esque pipe that even has a heat shield attachment. Tomos and Puch pipes are among a few that can be adapted to fit these engines, but usually require the fitting of an exhaust bracket on the the frame.
Variations: It appears that a few later models ('85 and post-'85-ish) have also been seen with a peculiar air-cooled cylinder. These cylinders resemble Puch, or Tomos since the cooling fans are radial rather than stacked. They may also lack the cooling fan and slotted shroud, and is replaced by a non-slotted 'scoop' type shroud. Newer models also benefited from a high-compression head, which is easily distinguished by a larger, more squarish, radial fin pattern. It also features an angled spark-plug hole. Fantic motors had a slight variation of this high compression head, though the fins are less pronounced, and the spark-plug inlet is not angled.
Older models may have a semi-circular crank, with or without a brass bushing in the upper (smaller) end of the connecting rod. New models have full-circle cranks with roller bearings in the upper connecting rod. Both varieties have lower (big-end) roller bearings. Like Carabela engines, Minarellis may even be seen as a kick-start. There are also a few that had built-in 'auto-lubing' system, similar to a Tomos or Garelli 'two-stroke direct injection' systems.
It is important to take note of the fan and shroud system on your Minarelli. They are typically found with two different sizes, maybe more, who knows? Usually older models will have a larger fan, and 3-screw, grey housings, while newer models may be seen with the smaller fan, and 4-screw, black housings.
Electrical: Most Minarellis had CEV (6932 or 6876) magnetos (6v 23w), though some Minarellis were equipped with Bosch (KB6-B212) systems (6v 18w). Part numbers and specs were taken from the V-1 Repair Manual.
Minarelli engines are super rad, and have a very dedicated following. Ride one, and you will understand. They are very reliable, offer a lot of torque, and are generally easy to troubleshoot. One (and in my opinion, only) downfall of these engines are the starter-clutch mechanisms. They are similar to a Puch design, except the center of the starter-clutch is equipped with a stationary ball-bearing rather than a flat disk. This bearing tends to wear out and fail, especially if there is excessive use of the clutch lever while the engine is in operation. Other components of the starting-clutch that may fail are one of two leaf springs that attach to the inside of the clutch cover, which should be checked and replaced in case of excessive wear. Other than mentioned above, it is safe to say that these engines are bullet-proof. There are plenty of aftermarket parts, including, but not limited to: 55cc Kits (unknown manufacturer) 64cc Kits (Autisa? rare) 75cc Kits (Polini) 80cc Kits (BRN, Bennassar, Imperial, etc) 90cc Kits (BRN, Bennassar, Imperial, etc) 2-shoe and 3-shoe centrifugal spring, centrifugal rubber, and/or washer-tension clutches (centers of clutches may need the tapers reamed in order to work on most common Minarelli engine types) Exhausts of all shapes and sizes, 80cc and 90cc (CV Racing, Bennassar, etc) Full-circle racing cranks (will need gasket modding to correct port timing in most engines) CDI's, including auto-advancing and auto-retarding CDI's (will need a lighting option to run lights-CDI works in the ignition circuit only) Carburetors and Intake Manifolds designed for bore kits The list goes on...if you need it, they probably have it somewhere.
Bearings and Seals: The V-series engines used two main bearings for the crankshaft, size 6203, non-shielded. They also used two output shaft bearings, size 6202, non-shielded. The crankshaft uses two seals on either side to cover the main bearings, size 17 X 35 X 8 (17 X 35 X 7 can also be used). The output and pedal shafts require three seals, size 15 X 24 X 5. One is placed over the output bearing behind the drive sprocket (be careful...this is a real bitch to put in without fatally damaging the seal), and the others are placed on either side of the pedal shaft. Numbers face outward on all seals.
Torque Specs: Engine studs and case bolts should be torqued at 7.3-8.7 ft/lbs. Intake and exhaust should be torqued 7.3-8.0 ft/lbs. Magneto should be torqued to 33.3-34.7 ft/lbs. Drive sprocket should be torqued 31.8-32.6 ft/lbs. Clutch should be torqued at 21.7 ft/lbs. These specs are taken from the V-1 Repair Manual.
Sparkplugs (gap at .024 inches): NGK B5HS or B6HS. Use a B5HS for colder weather, and a B6HS for hotter weather or kitted bikes. B7HS may also be used for kitted bikes, but should be used only when needed. A 'colder' plug won't prevent your bike from over-heating and exploding. Champion L86 or L89CM Bosch W 145 TI (does anyone use these anymore?)
Pictures to come soon. Feel free to correct me on any of this junk...there's probably a lot more variables than I've included.
Minarelli v1 service manual found on Mopedriders.org