Which exhaust & carb setup?

Hi everybody,
my engine will be a Polini 177 with Worb 5 Longstroke Special Lip, homemade reed cage with RD 350 Boyesen petals & carb 28/30 by scootrs.com. Time ports are already altered a bit, and piston and carter jobs are done as well.

Which exhaust would you suggest expecially for slow city riding and travelling?
Isn’t 23/65 primary too long?
Which could be a carb setup to start from?

Yes, I’m the same geoturbo of VOL. I saw you on the forum but than for some reason you disappeared… I’m sorry but you must have chosen so… All I can tell is that we miss you and your knowledge a lot!

A lot more people are switching to reed intake engines, and I can’t subtract from this! [;)]

I’m now looking around for some advices for my SUPER engine and found you [:)]

The feeling of different stability must come from the torque curve, the two JLs must have it lower so the feeling of boost (I believe the effect of the expansion exhaust is like a „turbo boost“) at lower speeds is greater… Sip & Scorpion comes out at higher speeds… am I right?

I believe my cruising speed will be around 90-100Kmh therefore…

Thanks,
ciao
Matt

Eventually I started the engine!
The sound is amazing [:D])

I still have some things to fix…
I only have the slow jet #38, is it too small?

Thanks, I met him at the Eurovespa 2005 [;)]

Original von geoturbo: Curare and how about a 22/65 primary gear?

--------It can be a good compromise.

I was thinking about the JL Right Hand… but is the JL RH2000 better? Is it lefthand? Does the spare tire fit?

---- No spare unless you use some spacer.

I don’t think I’ll go for the SIP or Scorpion since they are not good for traveling if you say they work only on the 21/67…

-------Not 21/67 but 21/65
But I feel they are better if you are after fast cruising speed (100- 105kmh).
If your cruising speed is around 90-100kmh go for one of the JL.
(it is a long explanation, but since the different power curve you will have a feeling of different stability from your scooter )

Thanks for the timing advice, I didn’t know it!!

you could also try to contac FurlanPX in the VOL forum, since I have had few e-mail exchange with him regarding the building of his engine that I guess it is similar to the one you want to built.

hello Geoturbo,

sorry I have just seen your question now. I didn’t look at this topic since I thought it was finished.
I already talked with FurlanPX yesterday I think he understood but in case…

hello,

the 23/64 gearing in my opinion is too long for general use. It makes sense only for travelling. Go for a 21/65. If you really need for a while a longer ratio you could always change just the clutch gear with the 23cogs spocket. (I think it is called this way).

For the exhaust:

if you want to use at any cost the longer gear ratio get a JL RH2000 or the JL Right Hand.

If you use the 21/65 you can go for a SIP or a Scorpion.

For the carb set up start with:

Slow : 42 (spare 45)
Main : 130 (spare
128
Needle : JJG (clip 3rd position from top) with JL
JJH (clip 3rd from top ) with SIP or Scorpion.

Get the timing right at 17 with the strobo. And consider that the marks on the flywheel cover are made for 57 stroke and not for the 60.
Spark grade NGK9, Bosch W3

Curare and how about a 22/65 primary gear?

I was thinking about the JL Right Hand… but is the JL RH2000 better? Is it lefthand? Does the spare tire fit?

I don’t think I’ll go for the SIP or Scorpion since they are not good for traveling if you say they work only on the 21/67…

Thanks for the timing advice, I didn’t know it!!

Matt

I don’t get the advice about setting the timing at 17° on a longstroke…
Let’s say the timing is set at 17°, when the spark lights up in the two cases (considering the different strokes of 57mm and 60mm) I know there is a different distance in mm before the top dead point…

But isn’t the distance in degrees the same??