Aprillia RS125 smallie engine

[lifes a drag]

see it here ,,
http://davedaniel.proboards.com/index.c ... hread=4934

[oldbiker]

exhaust wise, consider using the std aprillia one,just adapt it to fit and give it a longer reflective cone to suit your four speed box........also a slightly longer down pipe....
just an idea ,and if you could do this your self it could save you £100s
one off pipes can be very expensive,would not be suprised if you,ve had quotes of £500 plus.

I would agree with this idea. It`s got to be the best option

[Wayne Miller]

I would agree with this idea. It`s got to be the best option

Hmm, I dont know about it being the best best option, but its the one im going to take until I can get it done properly. At least this way it gets me on the road straight away. The I can rebore, tune and get the right pipe made later

[lifes a drag]

you may be better gettin an after market pipe like an arrow or JL then addapting that to fit , i think the standard pipes are a bit restrictive

[snoghound]

Charlie Edmonds pipe????

[Wayne Miller]

you may be better gettin an after market pipe like an arrow or JL then addapting that to fit , i think the standard pipes are a bit restrictive

Ive not seen many of these pipes going secondhand and the ones that were werent that cheap. The main idea is to keep the cost down initialy with the pipe so that I can go with the standard bore and tune and then improve on it later ie larger bore, better tune and matched pipe

Charlie Edmunds pipe???

Ive already spoken to Charlie and Im 99% sure he'll be doing the work later on in the year, I just have to finish off building the scoot and putting the engine together and THEN start saving again

[Wayne Miller]

exhaust wise, consider using the std aprillia one,just adapt it to fit and give it a longer reflective cone to suit your four speed box........also a slightly longer down pipe....
just an idea ,and if you could do this your self it could save you £100s
one off pipes can be very expensive,would not be suprised if you,ve had quotes of £500 plus.

So tell me more about adapting a standard pipe Sean?

Im now thinking that this is the best option for me now.

I dont really understand exhaust so a couple of questions

also a slightly longer down pipe....

Why do you say lengthen it? isnt this based on exhaust duration? I wont be altering this, do I still need to lenghten and why?

give it a longer reflective cone to suit your four speed box

The reflective cone, Is this the first or second cone? and what will be altered by altering this.
Are there any formulas that can be used to determine the length, angle required?

Sorry mate, Im just tring to understand what will have to be changed and why

[J1MS]

The original set up of the bike this barrel has come off probably has an exhaust that's more suited to a close ratio six speed box, or at least, less suited to a four speed with near to 25% difference between gear ratios.
The extra length should slow the pulse a little to & from rear cone to exhaust port, the longer taper on the rear cone helping to spread the power, although the peak power may be down, its probably going to be more user friendly with that cylinder grafted onto the vespa cases.

I think this would be why Sean would suggest this.

TZR Steve has tried modified bike exhausts with some good results, a good thing is they usually come already fitted with a reliable mounting bracket that may just need adapting a little to fit onto your casing, so it maybe worth a try.

[sean brady scooters]

sorry for not replying sooner,just a bit busy and hectic at the mo....its that time of year..
but Jims has basically explained things there very well..,bike pipes are often too peaky for road use on scoots,simply cos they can use a peakier (more powerfull)/narrower power band due to having more gears and closer ratios to keep it on the boil.......

for road use ,with only 4 gears...you need to adapt and change these a bit..,otherwise it may turn out to be somewhat all or nothing,
i was of course only generalising from what i have found in the past when adapting a performance bike exhaust to a road scoot one..,but if you have the time you could run through a few of the exhaust design programs to confirm...and adapt it to suit your requirements...
may i also suggest that you have a word with our member Adspeed about this....
he,s doing some very good work with pipes.........
and is also very good with smallies....

[Wayne Miller]

Thanks Sean,

Adspeed, PM sent