bogging at top end

[hondaracing 79]

i have a 98 300 ex its motor mods are dg pipe and silencer, uni filter, bored 20 over, wiesico piston when i am in 5th gear i can only hold the gas 3/4 if i go any further it just bogs out. WHATS THE MATTER WITH IT I LOOSE RACES AGAINST STOCK BLASTERS????

[Butters]

sounds as if its your rev limitar kicking in but i won't swear to that.

[Steve-o 400EX]

Your jetting could be off. I know when i rejetted my 400 when i got a new pipe and air filter, i jetted too fat and i was runnin way rich and it was boggin when i was wide open in 5th. Try messin with the jets and air fuel screw. That should be you problem, i highly doubt its a rev limiter. Try that and if its not that thenlet me know and i'll try and think of somethin else.

[da_rider26]

i have had this problem a many of times on my 400, dont know if its same as 300 but maybe. the boot that hooks to carb might be loose or off. mine bogs down in high gears when mine comes off

[CarzyRrider]

dg sux get a new pipe not your problem but dg makes u loose top end

[Teufel]

the jetting being lean or Rich could cause that . Also it may not be getting enough air. I ve seen it before

[hondaracing 79]

should i go up or down with the jets and wich jet should i change im not framilier with jetting

[Steve-o 400EX]

You want to change the main jet because that is what deals with the top end. Check you Spark plug to see if it is rich or lean. If you not sure on how to do so, do a search for checking spark plugs and there was a forum all about it. Have you rejetted it since you got these mods? If you have not you are most likely running lean.

Good luck.

[hondaracing 79]

ok i checked the spark plug and it was black so i went to the local shop and bought a kn power kit the filter and jets, i got to the carb and whoever jetted or tried to jet it before i owned it striped out the three screws on the top of the carb, what should i do?

[Steven]

get an impact screw driver at sears

it will get those screws out even if the are rounded in the middle so don't wory

get new screws from your local honda dealer