Project 100mph Moped

[dolly3900]

Hiya guys,

Slight off topic here, but kind of workshop related.

Just wondering if anyone has been following the Practical Sportsbikes' project over the past few months.

Basic run down is an old AR50 and they want it to top 100mph, taking on as much modification as required without the obvious "chuck a 250 lump in it" route of things.

Been some interesting steps in the project, talking about the jetting, reeds, rebore (obv's), gears, sprocket sizes, ignition and many other bits in between.

The current edition is I think coming to an end of the project with the machine being put on a Dyno and development exhausts being made to tune the lengths, fueling etc.

At the time of going to press, they were recording a huge 21-22bhp out of this little screamer and still had some work to go.

Is going to be interesting to see how much more they can wring out of it and how close thay can get to their goal.

I know this is not going to last for a huge amount of miles, especially at full tilt, but it has been a very educational project for those of us who take an interest in such things and goes to show how much, many of these bikes are throttled back due to price, value for money and reliability.

Mike

[Efes123]

Personally, I doubt very much they'll make it. They'll need to pretty much double the hp from the 21-22 they've currently got, not that that isn't seriously impressive. My guess is they'll get to around 80 mph, that last 20 is a step too far.
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[Vincent]

The old 50CC GP racers like Kreidler etc used to do about 120mph IIRC and had about 25BHP so if they really do have 22BHP, that's pretty good going for an air cooled engine. How long would it last though?
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Space Is Deep

[cb1rocket]

[27cows]

Honda and the like could get 100+mph out of their 50s because they had 12 and 14 speed gearboxes. The AR50 doesn't and thus it's high unlikely they'll hit the ton unless they're going to use ridiculous gearing and find an absolutely massive hill
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The RXS100: vehicle of choice for Chuck Norris

[Vincent]

[cb1rocket]

400bhp per litre that's really pushing it!
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Honda H100S2 Rebuild - https://www.bikechatforums.com/viewtopic.php?t=253852

[Alpha-9]

It's have to be something like https://static.blogo.it/motoblog/100mph-lambretta-dragster/100mph_lambretta_2009_01.jpg
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Fzr-600 1999

[dolly3900]

Will have to see next month, think they're going to do a proper road test rather than a a dyno based artificial mph

[dolly3900]

Will have to see next month, think they're going to do a proper road test rather than a a dyno based artificial mph

[Frost]

145mph

https://1.bp.blogspot.com/_PJX1UI4Hvy0/S8pn0Zv3BfI/AAAAAAAAA0U/29vMdYA7hd4/s1600/buddfabstreamliner.jpg

https://tomahawktuning.files.wordpress.com/2012/06/turbomotor2-579x769.jpg

So it's certainly possible depending on how deep your pockets are

[27cows]

Have to say, this talk of old race bikes does remind you of how entertaining things were without all the rules and regs of today. I do believe there was a 50cc triple and Honda had plans for a 50 V4 This kind of freedom brought about stuff like the legendary RC166. Racing would be absolutely fantastic if the only limit was capacity. Could you imagine it, 800cc V12 strokers and insane shit like that
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The RXS100: vehicle of choice for Chuck Norris

[dangerousdave]