Atomik Nitrous 140 starting problems

[Flynn629]

Ok cheers man, do you think a 26mm makuni would be good choice? Would i have to do anything to the bike with putting in the new carb? Thanks

 

[Blender]

mikuni's are good for all round use, i've had mine for 5+ years now, still goes well, always been a reliable carb. the only annoyance is that the air/fuel mixture screw is on the bottom of the carb, making tuning alot harder. you have to take the carb off in order to adjust it (which you will most likely need to do, as it will need to be fine tuned to your engine)

 

[my67xr]

swapping carby's will most likely just need some minor adjustments, adjust the mixture screw etc.
but, possibly could need a slightly bigger Main jet ?
ask the person you get it off, what jetting he would recommend for your engine size
sometimes they can fit the new jet for you, so it's ready to bolt on/adjust the mixture etc

the only thing with the mikuni is the mixture screw is hard to get at.

 

[Flynn629]

Theres one on trademe ( a second hand online auction site) which is a 26mm makuni brand new for $40. Would the main jet that it comes with be ok or will i defo need a bigger one? Thanks

 

[my67xr]

most of the china Mikuni 22/26 come with a #95 main jet, the 140 might need something around a #100 ?
but you wont know till you try tuning it to get it spot on.


just thinking too, the Mikuni will need a smaller i/d air filter, as it has a 42mm inlet, Molkt is 46mm

here is a Molkt for about $50 inc delivery to AU, (NZ might be more postage?)
http://www.ebay.com.au/itm/26mm-PIT...K_Motorcycle_Parts&hash=item58a9cecaa1&_uhb=1
another type 2 Molkt 26mm a bit cheaper
http://www.ebay.co.uk/itm/26mm-PIT-...110cc-125cc-140cc-PITBIKE-26-MM-/400586968391

 

[Flynn629]

Thanks heaps mate ill probz get the molkt one, hope she runs good after that. Ill still probally check vavle clearences and take her in for a service aswell. Thanks for all your help your complete legends your doing a great deed helping other people out with your knowhow. Cheers

 

[my67xr]

all good,
if you need help setting up the new carby, just post on this thread again.
save starting another.

sorry i missed your msg earlier too, just saw it then

 

[Flynn629]

Hey is this the pilot jet? Came out that hole

 

[my67xr]

yeah that looks like it, pic is a bit blurry


is the hole though the middle open ?
push a piece if wire through it to make sure, wiggle it around etc then blow it out
is the any holes that go across the jet in the smooth/threadless area ?
if there is, check that they are clean/clear too


then look into the carby where that silver Pilot jet screws into,
at the bottom of the hole there is a tiny hole that goes through to the main bore of the carby
that needs to be open/unblocked too
use an led torch or similar to look down inside it and check it look clean
blow it out with compressed air and reassemble it


once you have fitted it back onto the bike, start it up.
then turn the idle speed screw inwards to raise the idle speed a bit, about 1800 rpm, not too high
now the mixture screw, towards the air filter end of the carby, can be adjusted.
turn the screw out a quarter of a turn.
listen to the engine carefully,
if the rpms drop, then the mixture screw needs to be turned in a 1/4 of a turn.
the rpms should increase to what they were,
now try tuning the mixture screw another 1/4 of a turn in
if the rpms increase again, then try another 1/4 of a turn in.
if at any stage the rpms drop, or it starts running funny, then turn the mixture screw back out a 1/4 of a turn

adjust the mixture screw, until the engine is revving at it's highest/smoothest point
when you are happy it is close to perfect, then you can unscrew the idle speed screw (with the big spring) until the rpms drop back down to a decent idle speed.


now you can take the bike for a ride and see how it runs

listen and feel how the engine is running, if it hesitates or feels flat etc, take note when it happens, and at what throttle setting
eg splutters at 3/4 throttle

then come back and post up you findings
we can go from there.

 

[Flynn629]

Mate it wont even start

 

[Flynn629]

It will only start if i give it throttle then as soon as i take the throttle off it just stops

 

[Flynn629]

I think that something with the throttle might be off, when i try and tighten the freeplay it doesnt even tighten at all?

 

[Flynn629]

And sometimes when i try kick it over theres like no tension in it

 

[Flynn629]

https://vimeo.com/83468917 this is a link of me starting it

 

[my67xr]

so take the airfilter off, and look into the carby,
does the slide in the carby move up and down when you pull the throttle on?
and how far off the bottom of the carby is the slide ?

 

[zwebx]

Okay check the manifolds for straightness.. (and good gaskets and carby sealing surface if its bent)

do the valve clearances. clean carby..
then the bike will run.

 

[rotn50]

What plug is in it.

 

[Flynn629]

Yes it does move up and down when i pull the throttle,

 

[Flynn629]

Dont think the spark plug is the problem as if i give it throttle itll start but i get kickback and have to keep reving the bike, and as soon as i stop reving it immediately cuts off

 

[rotn50]

Dont think the spark plug is the problem as if i give it throttle itll start but i get kickback and have to keep reving the bike, and as soon as i stop reving it immediately cuts off

Sounds like a china plug, it could just as well be the plug mate, think simple when playing with these bikes.