grp 21 tuned

[rc8ws73uk]

help......
i am having some problems with the tune on my grp tuned, it runs fine in the beginning but after a minute it seems too lean out. and i have no rpm and very little smoke, temp goes up the lot. i have tried testing for a air leak at both the engine and tank (i am running a rc8 after all) but everything bears up well and it all seems air tight.
i have tried both grp and ninja plugs and it doesnt seem too make any difference.
am i missing something. any help please. i am struggling here.

[megacrash]

problem is the normal method of testing for an air leak in the rc8 tank will not work,

inside the tank is a filter and a piece of fuel tube that connects to the pick up,

that fuel tube tends to have a hole in it which only becomes affected when the tank starts to empty

easiest way to tell is next time you run your engine when you feel its starting to lean out check the fuel line that goes into the carb for air bubbles    if there are that would signify a internal tank leak

[Genesis46]

Mark, WIll you be at slough on the 21st? if so i'll bring a fuel tank i know is good!:)
Chris howe had a simular problem on his GRP... im a 808, he eventualy gave up

[rc8ws73uk]

hi Will, yup i'll be at slough on the 21st so if you dont mind i wouldnt mind borrowing that tank just too make sure.
I do have a mbx5 tank which i know will fit (with some subtle mods) so i think i may try that as an alternative.

[length]

i think chris ended up with play in his con rod

[lotus791]

.... it does sound tank related ,cable tie one into it just to try even to the spoiler . i have on one occasion changed the o rings on the needles for one guy here due to his tune drifting but yours sounds like a pressure prob .the air bubbles in the line is a good way to tell. try that first .

[rc8ws73uk]

thanks guys, i apreciate all the help i have a mbx5 tank which i think i will try, which i know is good. and some new grp plugs. i am inclined too agree with the tank problem. i was going too change it anyway as it has been nothing but a pain in the ####, but i am doing the tyro on sunday and want too get her going well for there.

all the help is much appreciated guys. i will let you all know how i get on.

Once again many thanks

Mark

[Genesis46]

Mark, wasnt your RB ok though with that tank?

[rc8ws73uk]

the rb was ok but when i changed the engine the tank needed to be changed as well so i bought a new one with the engine now i dont know what is what.

....update..... i did the tyro on sunday and i think its about sorted. just need too richen up the bottom a bit and i think i'm there, i do need some number 5 plugs though. but thanks mate its a good point.

[MR Piraterc]

the rb was ok but when i changed the engine the tank needed to be changed as well so i bought a new one with the engine now i dont know what is what.

....update..... i did the tyro on sunday and i think its about sorted. just need too richen up the bottom a bit and i think i'm there, i do need some number 5 plugs though. but thanks mate its a good point.

You will find that the GRP engines do require a tweek every race meeting