Phbh 28mm on lambretta SIL200 engine, setup questions.

[kejj]

Hi

I have bought a Dellorto phbh 28mm for my SIL 200cc engine from 2006.
I have changed the manifold and fitted the rubber to mount the carb and finally after fixing up the cable choke I've added the carb to the engine and it started 2nd kick.

My set up is:
SIL 200cc Stage 4 engine. Original set up, nothing changed or uprated inside the engine. Original gears and cylinder/piston.
Scootrs Stainless Steel Tuned exhaust.
PHBH 28mm BS
Main 118 (tried 125)
Idle Jet 55
Choke 70
AV264 Atomiser
40 Slide
Needle X-2 3rd clip down
200 Float Needle

To the questions:
The engine fires up correctly and ticks over. I am able to drive around in all gears on straight surface.
When I tried to drive up on a step hill I lost all power. Couldn't get the engine to rev up. (1st gear)
I then reduced the main jet from 125 to 118.
After this I could drive up hill but with minimal power. In first gear of course.
What can I do to try to cure this behavior? change pilot or adjust air mixture? Is the main to blame or the needle?

Additional questions:
Is the main Jet for the PHBH the same as for the Delorto sh 2/22?
Which rubber can I mount for remote air-filter? the one for the sh 2/22 or the one used on the SH 18/20mm ones (I think they were mounted to the 150cc and lower engines)?

[rosscla]

You can get an alloy bellmouth adaptor like this one, which allows you to use the standard GP type hose.

[kejj]

Thanks for the tip rosscla.

No one else that has an answer to my thoughts around jetting and scooter behavior?

[Darrell Taylor]

try moving the needle clip up onto clip 1 or 2 from the top or try an x 7 needle

[kejj]

I moved the needle to second clip and then first. I'm still far out of the scooters power band and thus cannot get it up the steep climb from the garage.
Next I will try the x7 needle instead and maybe with the AV262 atomiser.
Should I start the experiment from 4th clip down or at 3rd and then move up if it doesnt clear up?
Depending on the result I will try to move down in main jet.

[soosh]

If it helps,i had my stage 4 dyno`d on 115 main with X13 on 2nd clip with a AV264 with PHBH28 and PM pipe and static timing of 19 degrees.
The needle did end up slightly polished to richen but think that was more of Jeromes peace of mind,i did use a std X13 also in the end when the needle became worn and all ok.Hope this helps.
Cheers

[kejj]

Thank you for the reply soosh.
The main is now 115.
The needle is changed to X7 second clip, the atomiser is th AV266.

It pulls through fine now, I will have to do plug chops to see that the main is not too lean and the needle+atomiser doesn't give a blank spot in acceleration.

[soosh]

I'm also running a 300 float needle valve,you may want to think about changing yours to a 275/300 from the 200.

[kejj]

So i wont risk empty float bowl. To bad I already put an order to Sck. Next time! Will avoid full throttle till then!

[kejj]

Updates.
Tried the X7 on the first clip but it drowned the engine uphill so I moved it back to second clip.
Then I decided to start testing main jet from top again.
125 main made the scoot ride really bad on 3/4 to full. Only cleaned when going down to half throttle.
Same with 122, although a little cleaner.
Resided to 120 main. It runs clean.

I although get the effect as I decrease the throttle from full towards 3/4 and finally 1/2 that it cleans more and in a certain position even gives a little boost.
My assumption is that the 266 atomizer and the 2nd clip x7 is running cleaner than the 120 main jet.

The plug looks OK, although it's difficult to get any good color on a new plug nowadays. It needs a little running in. and maybe I could move down to 118 or 115 main eventually. Will have to be careful about that though.

I really should have added an EGT now, I get nervous when I'm running max speed max throttle down the road.