Minarelli won't reach high rpm's

I recently became owner of a 1974 Blanco by Intramotor Gloria. This ped has been sitting for a number of years and the previous owner had no luck trying to get it to run.

I brought it home as a challenge lol.

First I checked that the motor wasn’t seized. So far so good.

Then I checked for spark. Again I was lucky, there was ample spark at the plug.

That led me to fuel. I put some fuel in the cylinder and the ped started right away. So I figured with the bike sitting for a number of years, the carb would need a good cleaning. Boy was I right.

I removed the carb, and took it apart. Lots of varnish inside, and the main jet was plugged solid. I removed any rubber parts and soaked the rest in carb cleaner overnite.

Meanwhile I bought a new plug, drained the fuel tank, refilled with fresh fuel and installed an inline fuel filter.

I managed to get the carb clean and the jet unclogged. Float and needle valve seemed to work fine. I blew everything out with compressed air and reassembled the pieces.

Lo and behold the ped started up easily and ran like a top. It ran great for about an hour. Top speed was about 30 mph although I am only guessing since the speedometer was broken. After about an hour I noticed that it started to bog as I applied the throttle. I figured maybe a piece of dirt or rust made its way into carb so I pulled carb, disassembled and blew compressed air thru it all. I reassembled and put back on bike. Same problem. The bike starts easily enough, but seems to be flooding when I give it throttle. There is bluish smoke coming from the exhaust as well as black carbon like particles.

I have checked the air filter and it is fine. The motor runs the same with or without the air filter on.

If I blow compressed air through the carburetor, while the bike is running, the motor runs like it should.

To me it just seems like the motor is flooding itself when I give it throttle.

I have done a plug chop, and the new plug is quite black and carboned on the tip.

The motor is a Minarelli 49cc, 2.2 HP. The carburetor is a Dellorto sha 14 12.

Anyone have any ideas what might cause these symptons and what to try next?

Oh yeah, I did a compression test and the compression is 105 psi.

Any suggestions would be appreciated.


Re: Minarelli won't reach high rpm's

Harry Barfield /

it sounds like the bike is running rich if it runs correctly with extra air...lean it off a bit then do a plug chop until you get the correct mixture (the plug will look grey/brown)

Re: Minarelli won't reach high rpm's

Have you re-checked the float? Is it possible that the float has broken down, letting too much fuel into the engine.

You didn't soak the float in carb cleaner did you?

Re: Minarelli won't reach high rpm's

They only made .9 of a hp on the Minarelli V1's Check the level of oil on the gear box side and make sure your not burning the gear oil, been sitting for a while means most cases needs crank seals. Good luck. Clean the points off with a nail file?

Re: Minarelli won't reach high rpm's

Oh 105 is not good 120psi in the bottom line on these motors.

Re: Minarelli won't reach high rpm's

This has a dellorto carb sha 14 12. As far as I can tell, there is no way to adjust the air mixture on these.

Re: Minarelli won't reach high rpm's

The mfg. plate on the side of this 'ped says 2.2 hp. I will check the oil level tommorrow.

Yes I cleaned the points. Spark is good.

Thanks for the input.

Re: Minarelli won't reach high rpm's

I checked the float. It is in good condition with no leaks. Needle valve works fine. I haven't tried adjusting the float level but the float is level when the needle valve is closed.


Re: Minarelli won't reach high rpm's

Blueish smoke and carboned up plug leads me to think that the crankshaft oil seal on the drive side is leaking sucking in gearbox oil. It could also be that the timing side is also leaking causing your low compression.

Sounds like an engine overhaul to me

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