engine bogging down at high revs

[v12stuart]

hey
i have a cag pocky with a few upgrades including a walbro carby Ozminimoto - Mini Pocket Bikes - Product Detail , a fatboy exaust and new chain n sprockets (better quality) i'm finding that when im going flat out that the engine loses revs and all power until the revs drop then it goes again. this happens more often when the bike is hot... how do i fix this? can i adjust the carby in some way or does it have to do with with the ignition? i have no idea would be great if sumone knew what is going on

cheers,

[smokincag]

i dunno much about the walbro carby but they have a high and low speed needle to tune with. id start by turning the high speed needle all the way in then tune from there by turning 1/8th then trying again until u get a tune that u r happy with. hope this helps

[mac90]

it sounds like it may be starving for fuel at high rpm
go over the fuel lines fuel filter & be sure the vent hole in the cap is clear to breathe

if that dose not help you may need to adjust the H mix screw out 1/8th of a turn then test

initial settings for the H screw is all the way in then 2.5 turns out, once its set you fine tune 1/8th of a turn at a time in or out

in for less fuel out for more
dont touch the L needle low to mid range is ok as the H needle will determine high speed mixture

[v12stuart]

yeah thanks i thought it would have to do with the carby adjustment. i cleaned the air filter and had a look at the cap hole they're fine. ill change the carby settings because the instructions say to have it 2 turns out initially and it might not account for the exhaust upgrade. just out of interest will a Chinese 50cc engine max out when the spark cant fire fast enough or can it over rev and blow?

[racer182]

mate, it could just be top speed of the bike...
are you riding flat out in a straight line..
it could be hitting max revs....
hope that kinda makes sense..
may have to change front or rear sprockets
to get more speed from the bike...