Malossi 136cc + phbl kit => problem at low RPM

Schaltroller / Classic Motoscooters Vespa Smallframe
1

Here is my setup :

 

-ET3 engine with.

-malossi 136cc

-malossi reed valve (cylinder) + phbl 24 kit (default  jets) 

-Cone filter

-needle on the higher clip

-Vespatronic

-mazu full circle

-Transfers matched

-polini evo II racing exhaust.

All spy, bearing etc are new.

 

If i do a stop and go 'full thorthle' : Great acceleration, no problem.

 

my problem is that when i ride in group at "lower" rev (< 5000rpm) for a little times.

I can not accelerate properly.  It's like if the choke is on, but after 4-5 sec, the engine recover a normal (great) acceleration.  idle jet to big ?

What do you recommend for idle jet ?

 

Another "problem", probably not related. the engine vibrate a lot between 4000 and 5000rpm espetialy when decelerating.  any guest ?

 

Thanks in advance

Ferretti Fabio

 

 

2

Hi,

Is your sparkplug correct?

Have you tried to adjust the mixture screw? 

http://bristollambretta.webs.com/mixtureadjustment.htm

Regards.

3

Thank you

 

isn't 17 ok for ignition ? As i remember for the malossi 136cc the book say 21°. and i've read somewhere that for vespatronic you must add 4 to 5°. but maybe i'm wrong and that's why it vibrate so mutch. (with 17° i've practicaly no power at low rpm)

 

ps: thanks for the link, it will help for adjusting the mixture !!!

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4

I use Bosch w3as silver and I am very pleased. Concernig jetting it is very difficult to say anything from the distance but as a guide I used Max jet 92 with ram air filter. and min jet 60. (in a phbl 24 reed valve to crankcase induction). Ignition 17.

And I have just received this:

http://www.scooter-center.com/scoweb/pages/productdetail.grid?lang=en&currency=EUR&product=289278021890688&category1=C%3AC_V&category2=CAT

 

Regards.

 

5

any one from sip staff?

6

i've try sparks from 7 to 9.

and yes i have try the mixture adjustment. (realy hard to access it in the frame )

7

[quote user="alberogu"]

17º is for standard electronic ignition. If you have varitronic follow what the instruction recomends.

[/quote]

there is no instruction given with the vespatronic .. only wiring instructions.

the "book" of the malossi kit said 21°. but must i align to 25° ? ( 21° malossi book + 4° for vespatronic )

my phbl 25 have main 105 min 50 but i don't know the nozzle and needle ( it's the one given with the malossi kit carb and  intake direct reed for the malossi 136cc kit, so i think it must bee the right one for the kit). but i've try all needle position already.

 

8

17º is for standard electronic ignition. If you have varitronic follow what the instruction recomends.

For jetting malossi recomends for phbl 25, reed induction to the cylinder:

Main: 107, Min 50, Nozzle 264 AQ, Needle: D26 (in the second position), Gas valve 30.

Follow this and see what happens and share with us.

Best.

9

Hi,

align your vespatronic on 22°BTDC at 2500 rpm.

 

The jetting should work with the info you have-  best needle for this set up is a D26

 

[View:http://www.sip-scootershop.com/de/products/dusennadel+dellorto+d26+_22652600]

 

Regards