BGF rear friction engine

Discussion in 'General Questions' started by bilboby, May 14, 2010.

  1. bilboby

    bilboby Member


    I took delivery of this Chinese made engine after purchasing cheap from a well known auction site.

    Question: What are these 49cc rear friction engines like for reliability and are they sturdy enough for even the lightest (242lb) of guy's like myself. I've just finished fitting the complete engine & drive mount onto a Magna MB and thus now just waiting for this European Spring weather to improve before test running the finished motorized bike. Hopefully the engine will run longer than just a few miles hence has anyone had a bad experience using such an engine? I have a couple of more engines lying around the garage which probably could be adapted/used if required one of the engines being an Italian model? which came off an old Puzey EVO 2x Powerboard. Another motor again a Chinese model which alas despite my efforts on fitting onto the V-frame of another bike meant the back wheel would not turn. Thus this engine is still new & unused. I'll let everyone know how i get on after test running the BGF engine & any future further help concerning the other engines would be very much appreciated, many thank's.


    NB: I was informed by a curious nosey parker that such motorized bicycles are forbidden on French roads & Cycle path's, though i don't see the problem as ii'd of thought such modified bikes are exactly the same as riding a French made Solex or Velosolex or motorcabine?

  2. Happy Valley

    Happy Valley Active Member

    Sounds like you already made your purchase and you're just about up and running so you will soon find out most of what you need to know.
    A couple of further thoughts:
    Not sure if you swapped out the rear tire on the MTB but a smooth tread works best with FD. (I'd recommend slicks on both wheels actually since a knobby in front will cause quite a bit of vibration on pavement)
    The engine BGF sells on that drive is what often is referred to as a Mitsubishi clone type and I believe they service well but they do tend to be LOUD. After you run yours see if this bears out. There are ways to muffle down some of the exhaust note if you find it offensive however the more so you do so the more you can sacrifice power. After you start it up let us know what you think or for further thoughts on mufflers.
    I can't speak at all toward the regs in your area but here if I ride on bike paths I do so mostly without the engine running.
    Good luck.
    Last edited: May 14, 2010
  3. bilboby

    bilboby Member


    Thank's for the tip concerning the muffler also about replacing the tyres though the guy from BGF also suggested the tyre change aswell but didn't say which type. Has anyone an idea how fast these engines run as i'm told to expect around 25 - 30mph depending on weight size also the the fuel consumption though very good is again dependant on actual carrying weight, is this so? I'll let the forum know how the modified bike with the rear BGF friction engine perform's once we get some cycling/riding weather here. Jeez it's the middle of May & normally around 20 - 25°C but feel's like mid March with today's high only around 10°C, Phew lol that's hot.


    Last edited by a moderator: Dec 18, 2015
  4. bilboby

    bilboby Member

    Sorry for long reply:

    Finally got to try out this new beast:evilgrin: of a MB yesterday and finished the trial somewhat bemused. The engine started up okay and everything was going well until suddenly the back wheel wouldn't turn hence having to peddle hard up the hill. On inspecting the probable causes as to why the wheel played up i noticed that the drive roller was intermittently jumping thus not fully turning the wheel. The culprit drive roller came with the kit and look's like shoddy roller build Chinese workmanship is to blame (i'll post a photo on here later for any advice) as for the engine well being 2-stroke it's loud but seem's to perform okay for now, how long it'll last before it give's up? Who know's? I guess i'll just have to get my money's worth before it does give up, true are the words Buy cheap then you know what to expect. As for the drive roller problem any idea's on how i can get the roller to firmly rest on the tyre (original knobby tyre replaced with slick type). The rear engine + roller housing has been fitted exactly as described elsewhere on the Internet as no instructions came with the actual kit it's self. Hence it's highly like'ly that a replacement quality build roller will be required?

    Cheers & good riding
  5. 5-7HEAVEN

    5-7HEAVEN Guest

    Maybe the roller's not digging deep enough into the tire.

    Loosen the rear struts and midpoint pivot points. See if that allows you to push the roller down sufficiently. If it does, then secure all adjustments.

    You could try adding an extran muffler can onto your engine, using heater hose and relocating muffler to a remote location.

    The quietest muffler I ever used was an ADA S1 expension pipe.More quiet than stock mufflers, plus extra power.
  6. bilboby

    bilboby Member

    Cheers Comarade,

    Done exactly what you suggested concerning the rear struts & now i'm getting funny look's from people carriers who think i'm either the bionic man going up hill or the MB is a brilliant idea lol? Let's go a riding and have some fun....Photo's to come once i'm happy with the engine setup also changed the Magna Bike for a European Schwinn type low cruiser chopper.


    NB: I've also replaced the stock sparkplug for an active AX80 which seem's too give more power though that's only my assumption.