how fast?

mark1992 · Derestricted Danger Joined: 29 Sep 2009 Karma :

what would the top speed and acceleration be like on a standard speedfight 100 with a polini variator and rollers? due to them costing about £60 i thought it would make a good performance increase?

P.addy · Red Rocket Joined: 14 Feb 2008 Karma :

probably not alot, to be hnest for most 2 strokes, more power usually comes from a new exhaust..

alains · World Chat Champion Joined: 08 Jul 2004 Karma :

i agree . the best improvement is to fit larger block reed , race exhaust and a 21-23 carb .
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the worst day fishing is better than the best day working

RudiRulez · Two Stroke Sniffer Joined: 24 Jul 2009 Karma :

doppler s3r pipe, stage6 v-reed intake manifold and a 120kit are pretty much the best mods you can do for the speedy 100, and if you want abit more top speed after all this then get a gear-up kit.

im talking form personal experience here as i used to own one.

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

I can't advise on the Polini variator, but i can tell you that the more expensive Malossi multivar unit's are a real waste of time and money. Therefore i'd have to say that i expect the Polini to do very little for it.

If you must tune the bike then a decent pipe is the best and most useful mod you will ever make. I'd reccomend the expensive PM pipe over anything else, but a Doppler pipe would work fairly well too, if you get the transmission set up right to suit. The Doppler likes to run at 7600-7800rpm, and this is a bit higher than the better PM pipe.

1, Use a std belt, as all uprated ones i tried sapped power, were too weak, and too wide as well.

2, Keep the std variator, but for the Doppler pipe, you want lighter rollers, and the strongest clutch springs you can get. ( I had Malossi Yellows) and with the other mods i did the clutch was still engaging much too early. However keeping the std Variator will help take off i would say.

you can take off the snorkle off the air box, and may need some mild re -jetting to compensate. You should gain 5mph and 2bhp with a good pipe and set up.

The 120kit should be fitted before you even think about a bigger carb IMO, and a good mod for acceleration is to have 0.5mm skimmed from the head face, and then fit a BR9ES plug.

The above is not money well spent compared to a good pipe, and i think anyone will struggle to get a real 12bhp from a Speedfight motor due to the fact that they don't respond very well to tuning, and that the inlet into the engine is far too restrictive.

The Yamaha/Minarelli and the Moto Morini 100cc engines are much better and more tunable units too!

mark1992 · Derestricted Danger Joined: 29 Sep 2009 Karma :

how fast would it be then stevo with the pipe, rollers and clutch springs? thanks

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

Well according to the trip computer that i fitted on mine, the true top speed of the std bike was 54-55mph on the flat, and 60mph downhill. I did all my mods together and eventually got close to 12bhp and 68-70mph, but had a few reliability problems along the way. I spent £500 for 12-14mph extra! Embarassed

The PM pipe has been tested to add 2bhp over most of the rev range, and gives 5-6mph more than std. The Doppler pipe should be similar, but it will need more transmission tuning, rollers+strong clutch springs to suit. If you get a genuine 60mph from it afterwards then be very happy with it! They don't tune that well, and a much faster machine is the Aprilia SR125 or Italjet F125, both of which i looked at before getting the Slowfight2 100.

Some fast 50's with a race pipe and transmisson mods will hit a real 55mph, and get there faster than a std SF100!

Alexio · World Chat Champion Joined: 27 Aug 2009 Karma :

Wow, that's pretty much the same performance as my unmodified CG125 on a good day Confused

£500!? You can buy a CG for that Wink

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will never give up his CG. I look at my fuel gauge more as a progress bar than a fuel gauge.
G: With my GSXR I do often effectively use it as a scooter with a clutch in town.
ms51ves3: why does it need 500 miles? Are you teaching it how to be a piston?

stevo as b4 · World Chat Champion Joined: 17 Jul 2003 Karma :

The std bike gets away quicker than the CG125, but i think my old std CG would have had a std SF100 on top speed. The CG would always indicate 65mph on the flat, and rarely drop much below 60mph on hills. It was fairly slow but never really felt it if that makes sense?