Gori 200 jetting problems

[scandical]

I'm having problems jetting my mildly tuned li150 - series 3.

Looking to keep it original in appearance, but increase the performance for modern traffic, I've fitted a Gori200 sport, casatronic kit and BGM clubman.

I also increased the sh18 to an sh20 that came off a friend's sx200. I then fitted the BGM metal mash airfilter.

I was expecting to use main 118-125 but the best jetting combination is a surprising idle 50, choke 50 , main 102, atomiser 5899-2 It feels just right on short runs up and down the road but the numbers don't seem right. Anything above the 102 and it bogs/judders when moving off of idle.

With the airfilter removed completely it runs well with a 115, but I'm not keen on riding without an airfilter. Even if I use the BGM filter with a drilled airbox, I think it will only move me up to 108/110 main. Still seems too small...will this risk seizures/holed piston??

I'm new to Lambrettas, but assumed that even mild tuning would need up jetting from the from the original sh18 (105, 45), not down??

Can I have installed something incorrectly or have I missed something obvious? Any advice is appreciated as I'm lost at what to try next...

[scandical]

Forgot to say, ignition timing set to 24*

[gtwildcat]

Hi there, best advice anyone can give you is take it to a scooter dealer with a dyno, they will be able to set it up very easily for you. Also fitting a slightly larger dellorto
carb would probably benefit the set up. But if it was me I would get it dynoed by a good dealer and take their advice.

[Daggs]

If it bogs when moving off it's nothing to do with the main jet.
Settle on what air filtration system you're going to choose and jet to that.

[scandical]

Thanks for the replies.

Problem is that I live out in Finland. The scene here is smaller than tiny, so there are no scooter dealers/dynos to help.


I had a Jetex 22 on the shelf and tried that today. Same results though.

Bogging was probably the wrong word, I would actually describe it as spluttering. I assume the engine is getting too much fuel with larger jets and not enough air. With the smaller main it ran pretty smoothly from standing up to fourth gear.

With the small 45 idle jet, it would die at idle so I know the 50 is about right as it idles smoothly.

Maybe I stick with the sh20, 102 main, 50 idle and BGM filter then. Start running the Gori kit in and do plug chops...???

[Grumpy225]

Forgot to say, ignition timing set to 24*

24 at idle? That should be okay, maybe a little advanced.

I run that same kit with a Scootopia SH22 on a gutted air box, paper filter, stock exhaust. Running standard GP200 jetting. Your 20 carb should be at least running SX200 jetting. I'm at 400' ASL

45 idle
50 choke
118 main

[HxPaul]

I set and strobe both of my scooters at 17degrees BTDC,in my opinion 24 is to advanced with the petrol we use nowadays.

[holty]

I set and strobe both of my scooters at 17degrees BTDC,in my opinion 24 is to advanced with the petrol we use nowadays.

i think he said he is using casatronic ignition, so has advance and retard i think, otherwise i would agree with you 17 degees is a safe figure on a fixed ignition.

[Doom Patrol]

That 102 main would get my spider sense tingling. You're right, it does sound way too small. Even in a 20mm carb. What exhaust are you using, and what does your plug look like?

[scandical]

Interesting to hear that you have the same kit with a stock pipe Grumpy, and yet are still running a bigger main jet. What atomiser do you have fitted?

To be honest, apart from shooting up and down my road to feel how each jet combination works, I haven't done any driving, so the plug colour probably isn't a good reflection yet. I need to ride it a bit more with the 102 main, 50 idle set up before the plug can be read.

I have a BGM Clubman V4 fitted and I had assumed it would also push the main jet up a couple of sizes.