hi i have bought a Skyjet SJ 125-23 and it is the slowest bike i have ever come across! i mean really? what is the point in building a NICE LOOKING bike that you cant overtake a moped on? it is the spitting image of a cbr 125 but is slower than a retard on disco biscuits.......... can someone please tell me how to make this thing faster and more responsive, bearing in mind i am no expert at mechanics?......

simon, March 2008

Where are the valves on skyjet mine wont do no more than 55-60 at a push

sime, September 2014

hi does any1 know if the skyjet sj-26 fairing panel will fit the sj-23 thanks for the reply... mine is all original engine part and i can tell you I take 70 to 73 mph and it shakes like hell even with my 100 kg so I would tell you keep it the way it is...

Thanks for those who take time to reply

mathieu, May 2014

I have one my self I get about 85mph still wanted more but it shakes to much after big bore kit exhaust for cbr K&N upjeted full throttle 7 tooth spocket cbr parts mostly fit on also I have a skyjet 125 with the cbr 400cc in it with little modding on frame also on ebay atm check it out seach ebay with my name

BikeMods&sales, January 2014

Hi just got myself a kaiser ks125-23 to get my self to work and back just wanted to ask if anyone knows what the correct oil level should be as no dipstick on the oil cap???? Please help :/

Lee, July 2013

i i just bought a skyjet sj 125 are they good bikes

khany, November 2012

Does a cbr exhaust fit a skyjet sj125-27??
If so which one as I want something like a scorpion or something something bit more performance be nice if some one could let me know!

Ricky, August 2012

i have a yellow 57 plate skyjet sj 125-23 and i have had 70-80 out of mine and it beats alot of little cars off the line i would love to make the bike fast so i am thinking of a kN air filter and a race exhaust for a cbr 125. does any body know if the cbr race exhausts fit this bike and where you get the full power cdi unit from..?

Antony, July 2012

set valves to 8 and 12 and u get 66.8mph of satnav

dan, April 2012

My hits 80 and I have not done anything to it and my dad has drove beside me in his vectra doing 81 on his speedo also quite good at mechanical stuff my dad has dt 125 x and he has earthed the wires under his speedo and it gives him better speed and were not sure if it will work on my skyjet but dont want to do it if it breaks it just wondering if any one else done it

ahren moxon, January 2012

get a k&n and a yoshimuri system for cbr they do fit 95 easy 103 at a push

gaz, February 2011

the not over 7 though.... i thought that too when it seems to lose power and vibrate like whel you know. simple fix its actualy a flat spot. changed the spark plug for a iridum one and turned the mixture up 1/4 turn under the carb (low for improt resons) and its vastly better reving all the way round not sorted but livable not sure if a performace coil/cdi might compleatly sort it. next on the shoping list went from 55 top to 90. (untill the lory passed me yes the speedo is ****)

flame it, January 2011

Have had one of these bikes for the last 4 years clocked 10,000 miles
have had other 125s
yeah the skyjet isn't the best 125 out there but they are good
and before you say yeah but a two stroke will smoke you and do 100+ bla bla think a 4 stroke doesn't need a rebuild every so many miles
infact my skyjet engine has never been touched other than it's valves adjusting and oil changing
the old girl doesn't look her best but she's 4 years old and has been over so many times

not to change topic but if you want to get a few extra mph out of bikes wear leathers as wind resistance is a lot less than textiled
for example near me is a 40 road leading onto a 50 that's mph btw.
I have tested what it's like speed and acceleration wise between textiled and leather the quickest to 60 was my leather jacket and tight jeans the slowest was textiled and baggy jeans
with textiles i topped out at 55 and leather I got 63 with accurate digital speedo calibrated using a Rolling road

things like tyre psi as this makes quite a difference I am running 30 front 32 rear these were taken stone cold by the way as they should be this is with stock tyres and no not the originals I purchased them a year ago there starting to square off so I will be getting a new set and deffinatly not the same I'm going for something like bridgestone Ive witnessed how much better desent tyres are on a cbr

I would advise against increasing tyre width as the bike well the cbr was designed with these tyres
fitting wider ones will not increase speed or acceleration as it's not like the bike ever loses traction
The added weight of the tyres will result in slower acceleration and a lower too speed due to increased friction on the road


--- the tyres have a speed rating if you do mod your bike so it can go over the speed rating you will be screwed as braking and handling will be compramised and damage to the tyres will be innevatable


As for restrictions
the system is not restricted these is a washer in the carb that can be removed but this often does more harm than good

the exhaust is not restricted
there is a baffle in the exhaust that can be drilled out

if you are serouse about wanting more performance then
here's a list:-
better tyres- softer - higher rating and not larger than original
brakes - overhaul brakes - buy Honda cbr brakes they are better
new brake discs and pads
higher fairing screen
k&n air filter
wider fuel lines enlarge tank holes and carb inlet or get larger carb but not much point
take engine out and get a bremmel grinding device and open up inlet and outlet ports
stainless steel exhaust system
new endcan

INSTALL LARGER JETS - and tune poperly or have someone who knows what they are doing do it for you this alone/ correct tubing- can give you that new engine feel and extra top end and acceleration

NEW WHEEL BEARINGS FIRST!!!!!!

Change oil and clean all filters get rid of the buildup of crap does a lot of good even gives a few extra mph

new chain and sprockets
larger sprocket 1-2 tooth on front or say 2-6 teeth on back

full leathers

high octane fuel important !!!

I will be comming into some mines soon like £500 so I am planning on doing as much of that list as possible
I may also get racing rearsets - footpegs

I think that's everything although ive proberly missed something
a alternative would be get a beat up400cc
or similar paint it skyjet colours and put skyjet badge on
aswell as vinplate and number plate
i do not condone this as it is illegal
bit what the hey how is a cop gonna know if you don't tell them
I have done this before with a 50cc and put the play on a 160cc monkey bike and only go pulled once
the officer asked for my license
pointed out my rear L was dirty and I had to wipe it
then he asked what bike it was I said a monkey bike only 50cc
he didn't do anything to check other than take my plate for a description
which was -make- -colour- -owner-
and that was me on my way
with a un baffled exhaust too

bob, January 2011

Hi these bikes have a crb chassis but a cb engine
the cb engines are known for been bullet proof
as for getting 80-90-100+
thats impossible for the stock engine as it's not designed for racing or speed but reliability for commuting
also as for bieng restricted no these engines arnt they just have bafflers in the exhaust to reduce noise.
If propperly tuned with new exhaust bore up kand n filter new larger carburettor the bike could touch 90 in 5th screaming it's balls off but this would greatly reduce the relaibility and make starting a b##tard

If you just want your engine to run at it's peak stock power and run forever then I would surgest the following:-
change fuel filter and fuel pipe,
empty oil
clean oil filter even the hard to reach stuff.
New oil do not buy cheap.
Run engine ( if engine stalls then increase idle screw 1/4 turn will make starting easier too if you have trouble)
for about 15 mins atleast 5 mins in 5th at 55+
this ensures that the engine propperly hot
now adjust the valves can't think what to off the top of my head will say in a cg manual
now clean the air filter
and finally after miles of research I have found that v superfuel from shell is the best giving better torque and a few mph top end while the addatives in the fuel slowly clean your carb and clynder
I don't think I've missed anything if I have let's know

Also I'd like to point out that skyjet bikes are not crap there cheap and not built to run forever without touching it
you will need to maintain the bikes atleast weekly with oiling greesing ext
mines done 9000 miles over 4 years and it's still going strong the only problem is it was dropped a few weeks back so I had to replace the clutch lever, clutch cable as it was due and the left footpeg hanger that's it
I hope that it shows what regular maintenance can doo

Nathaniel, November 2010

ive done nothing to mine and myns not tht slow wheelies 1st,2nd and through 3rd and ive had a 115 on an expressway with a digital dial on my does shift

john, October 2010

i took my one out yesterday to run in fully i got 76mph but the bike i was with said that was about 70 on his bike . i found if you dont wind it up on hills it will slow down but other than that it does do 70 7000rpm i just got to sort the wobble on the front now :OS think i have a iffy tyre .

lee, September 2010

four stroke are not restricted in the first place they are tuned to do no more than 65mph even with full throttle cdi air mods etc , its a fourstroke not a two stroke there quieter and smoother

Peter, September 2010

I have a red 56 plate with only 3000km...
it is true that the bikes are slow but if yours is reading 80 then your speedo is ouuut.
i get 60 in fourth at 10,000 rpm then 5th slowly pulls up to 70 if my chest is on the fuel tank and even then its at about 10,000rpm.
youll need longer gear ratios if you want to go quicker.

Theres usually restrictors all over the bike nowadays, restrictors in the exhaust the block (engine) air filter restrictors.....it never ends because these bike are not meant to go fast.
there cheap and built badly.
save up for a better bike.

adamx10, July 2010

i bought a brand spanker 59 plate and got a bore kit and race exhaust and took it to a tuning specalist and now i reach 110mph flat out but it only a 125 wot do u expect why not get a car

josh, April 2010

i have a yellow sj125-23 on a 57 plate and mine hits just over 80 touching 90 and all mines got is a k&n filter ? apart from that and the full power cdi unit you can buy for them i dont think theres alot you can do mate i know you can get arrow and yoshimura race exhausts for the cbr 125 if it will fit on the skyjet ?

ryan, February 2010

just buy a new bike lol

mike, December 2009

i really dont know what your talking about, its not amzingly fast i admit, but mines not de-restricted and it goes 80mph no problem!
.. but on a agreeing note thats not fast enough haha.
i want to know how to get to at least 110mph because i know its possible.

Sam Waters, September 2009

70 mph in his dreams. i am a very handy mech and i bought one of these as a comuter, to my absoute suprise on the ride home i glanced down at the speedo to see the number 90, like shte, i new this was'nt right when the walkers crisps big rig blew me right off and left me in his warm exhaust fumes, truth is its slow no ifs no butts probbable bore out the jets mod the carb but i dont think its never gonna keep up with a reliant robin so use it for what it is £15 a year for tax £8 for a full tank of petrol that will then get you 250+ miles in my oppinion a slow but absolute brilliant spend of my £400 for my 58 plate 11 month old bike.

chris, August 2009

I have an 08 one, it's not fast but it sounds like there's something wrong with yours. Has it been run in properly? There is a full power cdi unit available for about £25.00. it will give more low to mid range power. I've not tried this yet as i've only just got bike, but i've heard that it does make quite a difference. Just remember that it's a 4 stroke copied from a slow but reliable honda engine, there is not much you can do to speed it up.

Rog, July 2009

Your bike isn't broke. I have a 58 plate and mine is very slow too. It wont rev over 7k while in gear so I'm fairly certain it's restricted.

I'm searching the net for instructions on how to do just that now :]

Pete, July 2009

your bike must be broke my son has hit over 70 on his and has no problem with keeping up with traffic on a national speed dual carriage way

marc, January 2009