Atomik Fury - Cutting out / Spitting and backfiring at high revs (PLEASE HELP)

[matty_02]

Hi All,

Just wondering if we could get some help.
My mates Atomik Fury 250cc is playing up. One weekend it was working fine, the next weekend it was cutting out.

It starts up fine and idles ok. But as soon as you give it high revs or try to take off it spits and spurts. And even an occasional Blue Flame comes from the exaughst.

We pulled out the carby and had a look. Even though we don't really know what to look for, it looked clean!! We then drained some fuel and tried it out again but its still doing it.

The bikes only a few months old.

Anyone got ideas on what it might be?
Your help would be much appreciated
Cheers
Matt

 

[Dreadful]

Try adjusting the carby ...use the search function there's a really good tutorial in there that'll tell ya all about it mate

 

[rodbox5]

Hi All,

Just wondering if we could get some help.
My mates Atomik Fury 250cc is playing up. One weekend it was working fine, the next weekend it was cutting out.

It starts up fine and idles ok. But as soon as you give it high revs or try to take off it spits and spurts. And even an occasional Blue Flame comes from the exaughst.

We pulled out the carby and had a look. Even though we don't really know what to look for, it looked clean!! We then drained some fuel and tried it out again but its still doing it.

The bikes only a few months old.

Anyone got ideas on what it might be?
Your help would be much appreciated
Cheers
Matt

Matt,

1. Check that the choke isn't self activating when going over rough terrain, as I've seen this happen quite a lot. Remember with Mikuni carbs (and China rip-off copies), the choke lever is up for "on" and down for normal running. Sometimes the lever gets a little loose and bounces up into the "on" position whilst riding.

2. If that isn't the problem, take the carbie apart and clean it. Also check the needle positions and make sure they are set on the correct notch. Whilst your at it, make sure the jets are clean and unobstructed.

3. The following link is for the VM Mikuni Carb manual, which will tell you how to get the best out of the unit. Spare jets for these are available almost anywhere.

http://www.mikuni.com/pdf/vmmanual.pdf

Good Luck with the job.

 

[pbk]

take off your fuel bowl on your carby and i can almost gurantee there will be crap in the bottom clean it out with a tooth brush and petrol i had the same thing with my bike and my mates bike sounds like crap in high revs

 

[HEL200]

everyone talking bout carbie but when i had this problem it was my spark lead....make sure your spark plug and lead are in top nick too

 

[Cactus Jack]

IF it's not your carb .........

Check and adjust your valve clearances . As new bikes wear in they lose clearance and that allows combustion pressure to escape past the valves . An inlet valve leak will mess up the signal at the carb and an exhaust valve leak can cause back firing ....

If your valve clearances are OK ...... then it HAS to be something wrong with the ignition (firing out of time while the valves are still open) ...

An intermittent spark can also cause back firing because unburnt fuel/air charge builds up in the pipe then explodes when the engine fires again ....

I had an old HT holden that had a cracked dizzy cap and it ended up blowing the muffler open like a sardine can ..... it felt like a bomb going off under the car ......

 

[someguywithapity]

well check everthing that you can (and good luck) OR it could be the exhust pipe maybe. my mate zamits bike does exactly the same thing, preety much. i cracked my pipe and it sounded all screwed up, but when i fixed that buy buying a new one it sounded like hot ****(perfect).

 

[$heepy]

or there is water in the exhaust pipe. it happened to me yesterday. i got it going finnaly for a while and it dried it all up and its running fine now.

 

[samual]

Man Just Burn The Scrap Metal.

 

[matty_02]

Hey hey,

Well, after a few nights in the garage me and my mates finally figured out the problem.

Initially we thought it might have been a Carby problem so we took that apart and checked it out (Didnt really know what we were doing though). After that we then remembered that during the week we installed a rear tail/brake light and in the process short circuited the battery.

From here we looked into everythin electrical. Eventually we took of the spark plug lead and replaced that with a mates one, took it for a spin and it was heaps better. headed to Atomik the next day, bought a replacement and the bike was running fine, until it suddenly cut out.

Rod you were spot on about that choke moving by itself. It was moving up and cutting out the motor.

So overall, it was the spark plug lead, and then the choke moving by itself. The bike is running sweet at the moment

Thanks again for all your help. Couldnt have done it without ya's.

Cheers
Matty

 

[doug27]

Hi All,

Just wondering if we could get some help.
My mates Atomik Fury 250cc is playing up. One weekend it was working fine, the next weekend it was cutting out.

It starts up fine and idles ok. But as soon as you give it high revs or try to take off it spits and spurts. And even an occasional Blue Flame comes from the exaughst.

Anyone got ideas on what it might be?
Your help would be much appreciated
Cheers
Matt

yes i got a 250 orion did same crap ,cleaned plug fixed done it twice,need a new plug.caused by wrong jetting from factory,too rich

 

[HEL200]

Hey hey,

Well, after a few nights in the garage me and my mates finally figured out the problem.

Initially we thought it might have been a Carby problem so we took that apart and checked it out (Didnt really know what we were doing though). After that we then remembered that during the week we installed a rear tail/brake light and in the process short circuited the battery.

From here we looked into everythin electrical. Eventually we took of the spark plug lead and replaced that with a mates one, took it for a spin and it was heaps better. headed to Atomik the next day, bought a replacement and the bike was running fine, until it suddenly cut out.

Rod you were spot on about that choke moving by itself. It was moving up and cutting out the motor.

So overall, it was the spark plug lead, and then the choke moving by itself. The bike is running sweet at the moment

Thanks again for all your help. Couldnt have done it without ya's.

Cheers
Matty

good to see it all fixed bro, enjoy

 

[moey23q]

Hi I a XMOTO 250CC Dirt Bike. I changed The spark Plug and i put a brand new carbeurattor and the bike still doesnt turn on cCAN ANYONE HELP ME PLEASE.
THANK YOU FOR ALL YOUR HELP IT IS MUCH APPRECIATED.

 

[sick150]

Hi

I have pulled out my old 150cc engine and fitted a 250cc engine with electric start connected the same coulored wires from my old motor but not the one to electric starter motor started the bike and it run ok but was breaking down at high revs changed the cdi to a new one put on a new carby and is still breaking down spluttering and backfiring ???? next i think i will check the vavle cleaance could some know what the vavle clearance is on a Zongshen 250cc engine and other engine specs.

your help would be a great help!!