Garelli Mosquito

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  • #12786


    March 22, 2000

    Necesito comprar una bobina de alto voltaje para el motor mosquito garelli 49cc para bicicleta. quien pueda proporcionarme este repuesto en buen estado avisar a osbra at

    Sheldon’s lousy translation:

    I need to buy a high voltage coil for my moped, Garelli Mosquito 49cc for a bicycle. Can anyone provide spare parts in good condition? e-mail: osbra at



    I have been notice that this post/thread is stuck for a very very a long time. I dont know why, but just maybe there is too little Mosquito Garelli 38A left intact in this word, or if so it just too dificult to repair due avalaibility of its sparepart.

    However, despite my knowledge and skill about repairing motorcycle engine is not too good, I was able to restore my Garelli Mosquito 38A. It just lying on my garage for almost 40 years since its last used by my great uncle. Despite the bike frame is intact the engine won’t fired up bcoz there is no spark/ignition. Common problem found in old motor/engine, especially for this clip attchment engine. I have conclusion just maybe the wire inside magneto is short out or burn out. Other problem maybe the magnet itself become too weak because it’s dirty, water/soil or oil leak due improper storage etc. You know what I mean if we talked about old stuff lying on the garage.

    With great encouragement, thank you for all resources avalaible in the intenet, eventhough I may browse it little by little,I manage to bring my Mosquito back on the road again. It’s back on its functionality, so it can start and run easily. But for originality, well in my case, due the lack and hard to find of replacement ignition sparepart, I must make some modification. I will explain later. But I hope my tips can give your some idea how to restore this old great engine.

    Basically, for common 2 old stroke engine, like Mosquito engine, I conclude (whereas I use to do my restoration) it need :
    1. Good bike frame and its peripheral to ride/to test
    2. Good ignition/spark to ignite the combustion
    4. Good air/oil/gasoline mixture to make the piston/engine run (the main engine itself)

    So here is the explanation :

    1. Good bike frame and its peripheral to ride
    It means your bike frame must ready for the engine to clip on. Fit new tyre/velg if necessary. Repair the chain, brake etc. In my case, I need to change dimension of my velg and tyre to common use in here (tyre:26 x 1 3/8) which is put on my solex frame bike. Lucky for my other bike’s part is intacy good condition. If you dont have a bike for the engine to attach, then how will you test the engine?? It’s hard (but may possible) to test the engine (turn the roller drive without pedalling the bike)

    2. Good ignition/spark to ignite the combustion
    Okay, it’s mean your magneto working in good order and it can generate basic electricity. Use AVO meter to detect the presence of electricity. If it’s none or very weak, then maybe you need to dismantle the magneto (be careful) and check the generator wire and magnet. In my case, the wire already burn/short out. So I must rewound it again. But it’s difficult to find the same size of original thin wire to generate strong current (in my country). Also platina sparepart etc will be very difficult to find.But I believe in European/Western stil provide it so it will be easy for you.So in this case, I will bypass the original wiring ignition. I use ordinary wire for commom motorcycle, rewound it, then resulting output of AC current arount 50V when pedalling. It comes from 2 cable. So, in case you need to modification, rewound the magneto wire to produce enough AC current. Then because it’s AC current, you can put either 1 of the cable to engine body for ground, better on cylinder head (around the spark plug). And then connect other cable to simple AC CDI UNIT (I use Suzuki RC100 AC CDI Unit). The AC CDI Unit need 2 input : 1 cable input from magneto and 1 cable input of ground (you may take it from the body). The ouput is cable feed to IGNITION COIL. So you will also need to provide good ignition coil to produce bigger spark. Remember, Ignition Coil also need 1 cable input ground beside the input feed from CDI unit. Then the output from ignition coil is High Tension cable lead to sparkplug. In my case, I can generate spark from this modification. I already bypass the original Mosquito wiring system, so I dont need to adjust the platina etc and cable sparkplug fm original mosquito.

    4. Good air/oil/gasoline mixture to make the piston/engine run
    For basic, it mean, you still have & need (at least) the original complete carburator, the air intake, the gas cable, the decompressor cable&valve, good piston & rings, crankshaft, good engine block&cylinder head & gasoline tank. Dont forget to clean the carburetor & tank (it may dirty & rusty). And then install it properly. No gasoline leaking etc. For sparkplug, you may use NGK:B7HS/BP7HS or DENSO
    W22F-U/W22FP-U (as long as thread & reach correct you only need to find the correct heat range).

    In my case, my main problem is only on ignition. So once I get the spark, viola problem solved, due all my Mosqito sparepart is still intact. I just need to clean,check and install it (fasten the bolt etc). So adding the corect mixture of gasoline and oil (you may trial and error because maybe gasoline and type of oil is different from the past) your engine can be fired up soon.

    Just for 1st trial to see if the engine working or not, don’t use /mix the oil in your tank, use pure gasoline to trick the engine for easy running. Then after engine running, add little oil (SAE20) in the tank. I made mistake by adding too much oil, so when trying to start the engine for 1st time, it’s very hard. The engine wont running and after open the sparkplug, found its tips very wet with oil mixture.

    Okay, for comment or question, I am willing to help you may write me on :
    I will trying to help as I can. But remember, my tips is (suppose) to work in complete engine which is problem more on ignition only.

    Thank you

    Attch is some picture of restore Garelli Mosquito 38 A
    [Image links to broken. Ed]

    • This reply was modified 3 years, 9 months ago by  mosquito.
    • This reply was modified 3 years, 9 months ago by  brough.
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