hi there, I recently bought a nrg 50, needed a new crank due to splines being worn out and half pulley just spinning up on the crank. i put a new crank in, while i was at it i put a new varitor and half pulley in it and piston and rings and main bearings and clutch etc, after that was all sorted started almost first time and idles fine on tickover, but when you whip the throttle open it just goes blah and tries to cut out. i have to say the bike had this issue before the fooked crank as well. iv'e got the jetting just up from standard but but tried std as well. when i put a piece of tape covering about 75% of the intake its revs stayed low but it would run and pull me along the road at about 15-20 mph, like i said i stripped the carb and cleaned and replaced o-rings, dunno how to check the auto choke but it starts fine and idles fine. onece warm i took the choke off and blocked the hole up and it made no difference, all intake ports and ex ports are fine as well , its just something to do with the fuel or exhaust i'm sure of it. anyone had similar issues? i would burn it out if it was insured (bought as a project)
heres a link with a vid. the sound might help someone diagnose? when i rev, the i have to let off quickly or it will just cut straight out, i have tried it with with the airbox on but it makes no real difference, only reason it's like this in the vid is because it was the first run after the rebuild
yeah i have quite a few special tools for splitting casings, presses pullers, holders etc, they were fitted correctly, i put a larger jet in today and a new manifold and reed while i was at it and it ran a bit better, it's just the idle is fine, starts first kick, revs up a bit then blam, after fiddling with it today i ran it with no airbox just while i'm fiddling with it and as soon as i cup the opening to the carb it starts revving up and throttling like it should, iv'e gone up in increments but am up to 70 now which i thought is a bit big, but if it runs better thats great for me. i just can't seem to get my head around it??
so why are you upjetting the carb? if its completly stock with the stock airbox it will run the stock jet.. the problem you are explaning sounds like oil seals/air leek/possible fucked cylinder
i was under the impression that if you de restrict a 50 then it needs upjetting? Bore is fine. Can still see the honing marks on the barrel. Put a brand new piston and rings in and mains and seals at the same time as fitting the new crank
Right! Today i reset the carb settings all standard jetting etc and cupped my hand over the inlet and it was ok revved up fine as long as my hand was cupping the inlet. As soon as i took it off at full throttle it bogged and almost cut out. Right i replaced the metal plate in the carb inlet and put the std airbox back on and guess what. No difference. So i took the airbox back off and cupped the inlet. And it ran as soon as i snapped the throttle right open. i don't know what else i do :banghead:
all screws done up tight and even went to the extreme on putting a hose clamp on the rubber arggh :rant: cheers tho mate
yeah i did raise the needle mate i'll be honest it didn't make a noticeable difference. I give up i'm gonna be sticking it in the trade it in a couple of days. Now the thing has sprang a leak from the centre of the casings. Its more hassle than its worth. Bet if someone looked at it they could fix it in five minutes but ive lost all patients with it. Ill stick to 125s i think. Piece of shite
Think you`ve found the problem there then bud. Water can get out so air can get in! Leakdown test is gonna show an air leak between the crankcase halves. Split the cases and start again with new mains and seals, water pump bearings and seal, sealant on the case halves,set the end float, lock it all down with a torque wrench set to the correct settings, new gaskets on the top end and dial it in from there :mrgreen:
what jointing compound should i use for the two halves? I used hylomar blue last time. Used it on my 180 before and it was sound. Who's runner joe? Most of my family stick to four wheels mate.
