WTF flames outta my exhaust

[GOTSPEED?]

wtf, i changed my exhaust from that bullshit bbr style piece of shit to an exhaust with a 32mm header pipe nd 40mm muffler. Its similar to a h-bomb but its called Power bomb. Ever since the change mi bike back fires and a quick burst of flame comes out the rear. What can i do to fix this?
PLEASE HELP
eBay Australia: pitbike thumpstar crf50 motovert pitboss 125cc 140cc (item 300125205811, end time 04-Jul-07 21:06:18 AEST)
Thats a link that shows mi exact exhaust but mines green

 

[Terra-moto-Ash]

Does it only do it when its cold? beucause if its cold u shouldnt not rev the shit out of it......

 

[GOTSPEED?]

It does it everytime you back off the revs

 

[Sidney]

I rekon it has something to do with the carby. Unignited fuel is reaching the exhaust and is igniting in there

 

[GOTSPEED?]

Yeh that what i rekon so its running rich but i dunno how to adjust it to make it a lil more lean. Its getting too much fuel yeh, anyone else know whats goin on

 

[darb110]

iy would be backfiring right and it just ignights into a flame

 

[GOTSPEED?]

yeh das it man, so how do u fix dis, coz if its not meant to do it it cant be good right?

 

[SIKSPAC]

mine does the same ay

 

[GOTSPEED?]

Can you stop it from happenning

 

[pegleg]

It will also do that if you have an air leak in the system, check and make sure that there is no air leaking from the exhaust where it bolts up to the motor.

 

[darb110]

i spose u could stop it but why its pritty sweet =P me and mi mate both got new pipes and his was blowin flames and mine wasnt... i was not happy!! ended up taking it back =P umm well it backfires case theres excess fuel comin out the pipe isnt it so id say your running her abit rich... well the fuel is wat is getting ignighted which makes your flame

 

[GOTSPEED?]

If it is running rich how do i adjust something to make less fuel go through or somethong like that or lean it out more?

 

[pegleg]

I take it you didn't like my advice! And flames out your exhaust might look cool, but I can assure you that it is not a good thing...

 

[darb110]

umm you can adjust it in your carby some how theres a screw i think i just dont know where it is

try searching through the posts for stuff on carbies

 

[Trashthumpy]

and dont pour nitro RC fuel down ur exaust, looks very cool but melts ur zorst....

 

[jwe97015]

id say your bikes running either 2 rich or not rich enough. make sure the ckoke aint staying on or what not and if that dont work then adjust the mixture srew.my 2 cents

 

[GOTSPEED?]

I take it you didn't like my advice! And flames out your exhaust might look cool, but I can assure you that it is not a good thing...

dude i no its not a good thing coz its not supposed to happen, but its 6.00pm nd im not guna start up mi bike 2 check 4 an air leak so i can piss all my neighbors off. trust me i will take you advice cheers bro

 

[jwe97015]

if u have a mikuni just look on the carb from the right side its pretty hard 2 miss a gold scew. now that i think about it thats where it is on all my bikes.

 

[GOTSPEED?]

I dunno if people are getting confused or sumfin but i dont want flames cumin out if my exhaust, and does any one know which one the mixture screw is

 

[Trashthumpy]

the mixture screw is underneat ur carby its a bitch to get to