Skyteam st125tr/mo/of

From New Zealand, 2 posts

Hi from NZ. I have a skyteam st200. Starter, solenoid, battery and side panels removed and would now like to increase the grunt if its easy and inexpensive. The other day I removed the airbox lid and it ran worse, meaning it would respond with increased jetting. Anyone done this before?

From New Zealand, 2 posts

Further to my last, as per below, this substantial improvement in engine performance was achieved for the price of a main jet, ie $5.
I bought this bike at about 18mths old with it having a few tanks of fuel go through it for NZ$1500 + $108 delivery.
I am 170cm tall and 87kgs, 48 yrs old.
I have made a number of modifications and have found these all to be worthwhile and successful.
As follows; Michelin 6 day event front tyre, Metzeler MC5 rear, 5 weight fork oil, fork gators, zeta enduro handlebars and zeta hand protectors.
I have used spacers to direct the exhaust muffler wider of the bike so it doesn't collide with the rear brake caliper on big landings
I have removed the plastics off the tank and the 2 panels which they mount on. The front mudguard has been fitted with a small mudflap. The battery seemed to be flat so I bought a new one. this went flat a few days later so I bought a new rectifier, but this wasn't the problem, so I decided to remove all unnecessary electrics and so went the battery, its metal mounting cage (the space is now useful for an emergency tyre tube), the solenoid and the starter motor. I bunged up the starter hole with a rubber wine barrel bung and screwed 6 screws into the bung to spread it and ensure it stays put, which it has. This is to prevent oil leaking out. The result is shedding overs 5 kgs of deadweight.
Then onto performance modifications. First was removing the exhaust pipe and filing the lumpy welds out of the neck of it (and painting it heatproof black).
Next was taking the top cover off the airbox and then experimenting with main jets. Standard in the sheng wey (keihin copy) is a 98 main. With the airbox top off there was a distinct lack of power so I grabbed a pot full of old weber jets and used a 110. An immediate response for the better so I went up to a 122 which proved too much, with exhaust quite black and spark plug black. Then a 115 which proved excellent, and I am yet to try a 118 to see if the colour remains good, as the richer side of things is the safer side, right up to the plug getting undesirably black. With the 110 low and mid was better but there was a tiny drop off at top end, whilst the 115 is super right through the range. We'll see if a 118 improves it further or if 115 is optimum.
I have also fitted a very small backpack on the front guard/numberplate for drinks/lunch/tools and what equates to shaving kit bolted onto the rear mudguard as a tool pouch. In all a respectable package, especially for the money! These machines offer nice pulling powerplant, twin crade Chome-moly frame, very good hubs and brakes and these above mentioned mods have improved matters substantially.