How do you de-restrict a Honda MBX50 Moped 50cc?

I can not figure out how to de-restrict my Honda MBX 50 Moped. I know the restriction is not in my exhaust, i have cut a few mil of the cylinder pull on the carboretta so it is not that, i have slightly bent the reed valve plate stoppers and that hasnt helped either. Can someone please shed some light to help me? I do go quite slow on it, especially up hills. It is a 1983 Honda MBX50/mbx 50 50cc Moped.

Thanks

Update:

I know that they are restricted somehow, as it says in a hains manual that they are restricted for the UK market due to road safety law.

Comments

  • Years ago my first bike was a CB50J, I think the MB and MBX are a similar vintage. I'm pretty sure that they were designed for the UK 16er laws of the period, so 50cc/30mph. I think mine would push 40 downhill!!

    Just did a search and came up with this site.........

    http://www.mb5.co.uk/7.html

    Looks interesting. But as usual be prepared to start throwing money around.

  • I had an MBX 50 as my first bike way back in 1997. I managed to make it a bit faster by buying racing reeds and a racing exhaust. But believe me when I say it really didn't make much of a difference. I eventually upgraded the engine to a MBX80 engine which had polished ports, polished piston, racing reeds and a sports exhaust, this really made a huge difference. The bike flew and could do 80mph. Saying this though, because it was highly tuned the reliability suffered badly, and the big end bearings eventually gave up after a month. The MBX80 engines can be bolted into the frame with very little modification. The only thing you need to do is make a bracket to fit the radiator, which is not present on the 50cc model. But overall, you'd be better buying a 125 and then doing your test. I spent hundreds of pounds of wasted money making an extra few mph. You might as well use that money on a bigger bike.

  • It can be done but it will cost a lot of money effort for a very little performance boost. Its not just turning a valve as is the common misconception.

    Its like tuning a lawnmower to cut grass faster, it'll work but the benefit is minimal.

    You'll have to buy new engine parts and replace old ones with new expensive parts, you'll need to have some mechanical skill to do so too.

    Just sell it and get a proper license and buy a 125cc Motorbike

  • Not sure because of its age.. But mopeds/scooters now are restricted by pipes etc.

    But the most easy do-it yourself restriction is in the variator, where you take the side casing off on the left side of the bike. I've found a video for you...

    http://www.youtube.com/watch?v=YMeqjmjp_zg

  • The reason it goes so slow, is it's a 50cc engine! It is not restricted, it just has no power.

    Get a motorcycle license and a 250cc as a minimum, then you'll see some improvement.

  • Buy a ferrari

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