engine stumbling at high rpm????

[Tilly819]

hi all

have a wee problem,

when i open the throttle smootly and accelerce gently in 1st gear its all ok as far as i can tell
then when i change up to second and give it some its ok till about 6000 rpm then the engine starts to stumble/ splutter... this is the same throughout the gears.

engine is a 2002 honda super blackbird on EFI

now the only thing i can think it might be that is obvious to me is that i have removed the air box and just have ITG socks over the trumpets is this lightly to be part of the problem i though iniialy it might be turbulance from the bonnet scoop but i have blocked that off and the problem is still there..

any ideas??????

tilly

[AshG]

put the air box back on and take it for a drive with the bonnet off. bike engines are very very sensitive when it comes to induction.

what is the max rpm? you should still pass sva as long as the emissions are ok tbh.

did you get your new temp sender? it could possibly be that doing it.

[HandyAndy]

Don,t panic, it sounds like the engine is getting to much air at a critical revs, basically you,ll need to have it set up on a rolling road to get the "stutter" dialed out of it, it just needs its air / fuel ratio setting up correctly.

cheers
andy

[Tilly819]

thanks ash i thought it might be that.... unfurtunetly i dont have the air box anymore..

a chap on locostbuilders recons it might be running lean....due to like you say a change in air charicteristics...recomends maybe a power comander to adjust the fueling in conjuction with a power comander.....which i think might be good since then with it accedently fir the forced induction in a year or so it will alredy be there.....

your thoughts?

tilly

[flyerncle]

Is the manifold heated and if so is it hooked up,there is a possiblility it may be freezing up across the jets at high revs.

Just re-read your post EFI wont freeze !

[AshG]

its injection so wont be heated. find something to restrict the air flow and see if it improves. it will as said most likely be under fuelling. most people have a power commander on it

have a chat with slimtater i think his has got a blackbird engine in his. if its running lean then you should hopefully be ok on emissions just keep the revs lowish on the drive down and don't hammer it or you will blow a hole in one of the pistons.

[AshG]

did you sort out your temp sender?

I thought blades and the blackbird hated themselves when you junk the airbox?.

[Tilly819]

thanks guys this is all good info, i think the power comander may be the way to go with a lambda sensor so i can set it up myself, as for the temp guage ash nope its still not working, no idea what it is so i think im going to blank it off for IVA so its "not fitted" then i will probley get an after market one stick it in the top hose and i was thinking of getting an aero screen for it so maybe incorperate the water temp guage and lambda guage and maybe an oil gauge into the back of the aero, think that would look quite smart.

tilly