GP 200 jetting help

[phil99]

scoot is unrestored 200 dl all original

continual problems with the 6 volt ignition so upgraded to 12 volt variatronic ignition, was advised by cam lam to up the jets.

the barrel is at 67 mm

the original jetting is pilot 45 main 118.

increased the pilot to 48 and the main to 122 then 123 then 125 and now at 128 after plug chops it still shows its running lean

tried 130 main and it wont rev into it

it starts fine and ticks over ok but up to half throttle its 4 stroking when you open up the throttle it fly's

fitted a brand new plug rode 19 miles quite hard riding and then rode this 1 mile straight road into a head wind over 3 quarter throttle, pulled clutch in turned off coasted then checked plug looked lean







is anyone running a variatronic on a standard 200?
any advise please regards phil

[CambTim]

Phil,

I think you need to check what atomiser you have.

Are you running through the airbox still,and does it still have the snorkel in it?

If you live in Cambridge area let me know, I am sure I can help.

I have a Varitronic, 198cc iron barrel, 22 dellorto thru airbox.

Tim

[phil99]

hi tim

thanks for the reply.

the carb is the original sh2/22 running through air box

the atomiser is 5899

i live in the new forest hampshire

i brought the variatronic from cam lam

the only thing i have changed from standard is the ignition, i don't see how the jetting is so far out

what jets are you using?

regards phil

[CambTim]

Hi Phil,

The atomiser should be a 5899-2.

However often the atomisers have been drilled out.

If you are running a standard box pipe your main jet should be no bigger than 125.

The main jet is for higher RPM's although it can affect upper mid range.

I think it most likely your atomiser is either wrong or has been modified.

I have had some success with a 5899-4 Atomiser.

The is loads of info on Atomisers, and basically the numbers have no relation to leaner or richer, as I understand they just have an effect on mid range and profile. the cross holes vary too.

I have re read your post and keep thinking Atomiser. So maybe you could try another, original ones are rare and hard to come by. I believe Allstyles have remade ones as might Scootopia.

This is my opinion and I am not an expert, but I have messed with SH22's quite a lot.

Have a look in the airbox, the should be a snorkel in it which flows the air from scoop to carb mouth.

I hope this helps.

Cam-Lam have a copy of the original jetting chart on their site which is always a good place to start.

[phil99]

hi tim

the atomiser is 5899-2. i have ordered a replacement from allsyles in case the original had been altered.

il give it a try and check the plug colour

thanks for your help phil