polini 177

Hi, I have a 177 polini,running with 28 mil dellorto carb & gas flow crank.The ports have been matched both on the inlet & the top end.Ive changed the ignition over to electronic & she starts no problem.When the choke is out response is good,however when the choke is off it becomes slow response and cuts out.Ive tried advancing & retarding the timing,and cleaned the carb again.The main jet is a 105.Can anyone help as this is the last problem keeping me from going to the first rally this season[:bounce:]

happy to hear you have solved the prob.
Just for the hell of it try also this set up and compare it with the one you have it now, then choose:

main 108
needle X2
clip 1st position from top

You already have the needle maybe need to buy just the 108 main but it doesn’t cost that much.

…and thanks for the beer offer.


this means you are running a little lean. Try to put a 108 main jet and check the carb is well tight on the rubber manifold to avoid any air leak. Try, see how it goes and let us know.

…if you run at 21 the engine will run flat at high rpm and you risk to make a hole in the piston even if you are running a little on the rich side. Just turn a coupple of mm to retard more the timing.


I didnt understand well.
When the choke is out response is good however when the choke is off response becomes slow. Out or off it is not the same thing? So it has a good response or a slow response with the choke out.
Sorry english is not my language and maybe it is me that can’t understand.
Please say it in other words.

sorry what i ment was when choke is on it responds well,when choke is off throttle is poor.Hope this is better.[[:O]]

Thanks for your help will try this out.will let you know,Gary. AFSC

ive changed the needle from x2 to x5 second notch from top.This seems to have done the trick.Must thank you for the advise you have given over the last few weeks,its much appreciated.Hope we meet over the 2005 season I owe you a beer Gary, Armed Forces Scooter Club. [:drink:]

well today ive set up the strobe light.I have changed the ignition over to electronic & surprise it was well out.Have drilled & elongated the slots in the stator plate its now running at 21 degrees,i know it should be retarded more but will see after uelzen.the 108 jet is fitted just have to play around with the x2 needle,its running rich so wont have any problems with seizure.Just thought id let you know. Cheers Gaz;D