Hi guys 
just needed a little help with my little lt2 ,
iv had here running on the road now for around 2 months and she done about 35 miles on a fresh engine and crank rebuild, I now it’s still early days but is he feels abit sluggish in the middle range .
She’s running all stock jets and floats are set as per manual, she starts on first kick every time and sounds lovely, Iv recently moved the needle clip from the Center position and put it down 2 slots so there’s only one slot left underneath , which has improved the midrange alot but I still think she should be better , I was planning on putting afew tanks of fuel through her first to run it in more , I’m not a wizard with jetting so though u guys might help ? Maybe I’m asking to much of the little 100cc , Iv tacken her upto about 40 mph but don’t won’t to push her to much at the moment, she’s been rebord so should I be running a bigger main jet anyway ? It’s got a standard 120 main in her at the moment,, any help would be great , thank you Hi guys 
just needed a little help with my little lt2 ,
iv had here running on the road now for around 2 months and she done about 35 miles on a fresh engine and crank rebuild, I now it’s still early days but is he feels abit sluggish in the middle range .
She’s running all stock jets and floats are set as per manual, she starts on first kick every time and sounds lovely, Iv recently moved the needle clip from the Center position and put it down 2 slots so there’s only one slot left underneath , which has improved the midrange alot but I still think she should be better , I was planning on putting afew tanks of fuel through her first to run it in more , I’m not a wizard with jetting so though u guys might help ? Maybe I’m asking to much of the little 100cc , Iv tacken her upto about 40 mph but don’t won’t to push her to much at the moment, she’s been rebord so should I be running a bigger main jet anyway ? It’s got a standard 120 main in her at the moment,, any help would be great , thank you  

What a lovely little bike.

If you are taking it easy, I would not worry too much about the main jet, concentrate on the needle position as this controls the midrange.

Generally, you tune a carb by first getting the pilot right, then the midrange, then the top as each one affects the next.

If you are running stock jetting and the idle is fine, I would assume for now that your pilot jetting is fine.  

So you need to find a brand new plug, ride to a place where you can hold mid throttle for a mile or two, swap the old plug for a new one and ride the bike on mid throttle only for a mile or two.  Kill the ignition and coast to a stop without allowing the engine to idle.

Pull the plug and note the colour.  It should be a tan colour in the central electrode porcelain.  A darker brown is fine at this stage of your breaking in process.  A white or lighter than tan tip is a big no no and the needle needs raising.

A black tip with needle bottomed is due to wrong, bent or worn needle, wrong emulsion tube or wrong slide.

Hi mate 
thank you for the reply and your very helpful message ,
iv adjust the needle clip down to the 4 slot , is it ok to try it on the 5 and final slot ? And see how she runs then ? Allso if she runs better on the 5 slot should I go for a bigger main jet ? It’s got a standard 120 at the moment, should I go to 130 ?? Thank you 

Without doing a plug chop as I described, you are literally groping in the dark.  Engine damage could result from going too lean.  It is possible that a lean engine could produce more power, but more power equals more heat and more heat than the engine was designed for equals engine damage.

As for changing the main jet, I refer you back to my previous post..  Get the midrange right before doing anything to the main.

Hi mate 
how does that look ? 
Did my best to do what u said 

Perfect.  Now get a few more heat cycles / miles under its belt, then do the same (brand new plug) with the engine at wide open throttle.  Same result and your jetting is spot on.

Ok mate 
thank you for your help , cheers