Exhaust expansion chamber

[phonesurgeon]

Finally my 125 rebuild is getting close to the finish line.

As i now have an A2 licence i was thinking to get a few extra bhp.
The bike: Aprilia Pegaso 125cc 2T, same engine of RS(rotax 122/123).

Now i need to open the expansion chamber and take out any possible restrictors... bike is 1991 and never made for UK market.
I don't have the oxy acetilyne(or however it's spelt) and moreover i have no welding experience, at all.

So i was hoping any kind souls with the right equipment, could help?

[Fizzer Thou]

Is there a restrictor in the exhaust?Anybody with oxy-acetyline use it as a cutting device and will easily blow through the thin skin of an expansion chamber.Is ant restrictor in the exhaust port end or in the outlet tip.Any person using an oxy cutter is likely to ask where you want cutting,so make sure you get the correct end.
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Just talk bikes.What else is there?

Always have a 'Plan B'

[Kickstart]

Hi

Would be very surprised if there was anything in there designed to restrict it. Possible exception being the catalysed version sold in some markets.

However I expect almost off of them in the UK are either official imports or 2nd hand imports from Italy. UK ones would be restricted by leaving off the power valve and fitting a blanking plate without anything extra in the exhaust. Italian market one wouldn't have been restricted (no limit for 125s in Italy back then).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[phonesurgeon]

Stands corrected...

Keith mine came from Italy in 2002, and i thought being same engine as the RS125, i thought the exhaust might have been...

The powervalve is present and fully working! ok so it will be a case of 34mm carb, cone filter and sport (read... it will sound tinny even more) can.

Basically not worth the hassle! Cool cheers guys for clearing that up for me!

[Kickstart]

Hi

What year was it made? Thought all the Pegaso 125s were from the early 1990s.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[Livefast123]

You really don't want to fit an cone filter to a 2 stroke Keep the airbox unless you want to lose performance.
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Current ride - Yamaha MT-07

[phonesurgeon]

Keith mine is a 1989.

Livefast i ain't gonna bother with all that... keep as standard, otherwise is gonna be a nightmare trying to correctly jet the 34mm one!

[Kickstart]

Hi

Shouldn't be any restriction then (again assuming it isn't a catalysed bike - mainly sold in Switzerland I think).

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing