Atomik Nitrous 140 starting problems

[Flynn629]

Nah its sweet it just has air bubble when float is full up. Just cleaned out carby and checked that. Its all sweet. Going to a mates and gonna get new spark plug cause dont have right size socket what type spark plug do i need? Thanks

 

[my67xr]

it's an NGK C7HSA, or if you can afford it get an Irridium CR7HIX
they give a better life, don't foul as easy and give a better spark.

and the socket you need to remove/install it is a 5/8" Spark Plug socket. (Ford 302/351 Cleveland's take the same socket)

make sure you don't over tighten it , start it by hand, then use the socket, turn it in until the washer touches, then go just a bit more for the washer to seal.
it is easy to strip the threads in the head, and or snap a spark plug if you do it up on an angle too.

 

[Flynn629]

Spark plug was the problem , its going good now , this is old spark plug.

 

[Flynn629]

am i running a to rich mixture? Is this why its so black? Thanks

 

[Flynn629]

This is new plug after a few minutes of idleing

 

[GooseMan]

Yeah I would say it is rich, the fat porcelin bit in the centre should be a coffee colour. Have a read of some if the tuning threads on Here.

 

[Flynn629]

Ok do i turn the mixture screw clockwise to lean it out?

 

[Blender]

Ok do i turn the mixture screw clockwise to lean it out?

nah, with mixture screws its the opposite of a tap. e.g. the more you screw it in, the more fuel it will allow in, and less air. screw it out about half a turn and try a plug chop, and see how it is then, and if you need to , adjust it according to what it needs

 

[my67xr]

you cant tell anything by checking it after idling.

at low - mid rpms, the plug will usually come out looking brown or black, especially when it's been idling/ putting around for a while

you would have adjusted the mixture screw already to set the carby up.
the mixture screw only really works from idle to 1/4 throttle


to check the plug porcelain colour, you need to do what's called a Spark Plug Chop.

you need to do a long run (slight incline if possible) holding it at wide open (full) throttle for 20 seconds in 3rd or 4th gear.
then turn it off, close the throttle, and come to a stop, then pull the spark plug out there and then and check the colour.

the perfect mixture of fuel/air will give you something around a tanish/coffee colour.


a spark plug has a specific heat range, C7HSA, so when it is running under load and at full throttle,
the plug will reach a certain temperature, and will it's start self cleaning stage, by burning that black fuel off the porcelain.




if you do a Spark Plug Chop,
and find it is still a dark colour on the porcelain,
then you may need to remove the slide out the top of the carby,
and then the needle from it, and remove the clip, and set the Needle clip to the top notch,
then refit it all and give it another WOT run and recheck the colour


if you find it is still too rich, then you will need to order and fit a smaller Main Jet to it (the bigger jet in the middle underneath)


but try it out for now, take your spark plug socket and ratchet with you,

and let us know how you go with it

 

[Flynn629]

Bikes going fine, had a good rise yesterday, but one thing, when im at quite low revs and i go straight full throttle the bike will bog and if i dont let off the throttle itll cut out. What do you think causing this? Thanks

 

[Blender]

Bikes going fine, had a good rise yesterday, but one thing, when im at quite low revs and i go straight full throttle the bike will bog and if i dont let off the throttle itll cut out. What do you think causing this? Thanks

it sounds to me like you've got to lean of a pilot jet. what # jet is currently in your carb?

 

[my67xr]

can you blip rev it with out it hesitating ?

 

[GooseMan]

Tuning issue. Refer to threads dedicated to tuning, it has been talked about a lot on here.
http://www.miniriders.com/carby-tuning/20778-carburettor-tuning-guide.html
http://www.miniriders.com/carby-tuning/25033-carb-jetting-tuning-dummies.html

 

[Flynn629]

Yea i can blip rev it without hesitating, its only when at very low revs and i go full throttle. And also when i loosely put my hand over back of exhaust and rev motor i get black stuff on my hand. Is this a sign its running to rich

 

[my67xr]

sorry to have not replied earlier,
i tried to look at your Attatchments/pics, but i can't see them for some reason ?


you have a few pages going on in this thread now, i have forgotten a few details.

so it doesn't hesitate, but it does ?

did you end up replacing your Ignition coil ?

and is your air filter oiled ?

 

[Flynn629]

Yea it does hesitate when in low revs , but only when i go full throttle otherwise it doesnt, havent replaced coil, and have airfilter oiled, and also if i put the choke on itll just cut out. Thinking this is cause theres to much fuel going in? So running to rich? Gonna do that test mayby tomoro. And also bike takes a few kicks to start when it would start first kick when i went out for first ride on new spark plug

 

[my67xr]

to do the plug chop, you really need a basically new spark plug
if your new one has oiled/carboned up already, it will take a long/decent few runs back to back to get it cleanish again.
might be worth taking it out, and sitting it in some petrol overnight, then give it a scrub with an old toothbrush
it may clean up good enough to be able to use it for the testing
how much are they over there ? around $3-$4 each ?

 

[GooseMan]

Yea it does hesitate when in low revs , but only when i go full throttle otherwise it doesnt, havent replaced coil, and have airfilter oiled, and also if i put the choke on itll just cut out. Thinking this is cause theres to much fuel going in? So running to rich? Gonna do that test mayby tomoro. And also bike takes a few kicks to start when it would start first kick when i went out for first ride on new spark plug

Or not enough air? what did you use to oil your filter and how much oil? Too much oil on the filter will be like having the choke half on.

 

[stoozo]

I've got a cracking idea....BUY A NEW MOTOR for $100 from ebay....one that starts and runs perfectly....2 months and its not going. I know you tech boys love problem solving but seriously this thread is ridiculous!

 

[GooseMan]

Does it come with a carby tuned for it?