hello. my yamaha jog r 70cc polini sport is making a funny knocking sound. someone said maybe it could be the rod bearings. could this be true and how can i check them? thanks
You mean the small end bearing in the crank ? You take your bore off, remove the piston and you'll see it. If they'res any missing it'll need to be replaced. Also replace your circlips too. Never put old ones back in.
Read again. They are under your piston. Remove your piston and you will find it in the top of the crank. They're called roller bearings mate.
ok thanks. and do u think this could be the problem to the annoying knocking sound? and what will happen if it is that and i just ignore it? will it break more things?
Mate it costs pretty much nothing to check it. Just a new set of circlips. And if it's coming from the crank area it will probs go bang lol. You sure it's not rollers or clutch or gearbox ? If you don't feel confident doing it you'll have to take it to do it for you,
cant check it just yet anyway because ive just had a hip operation but i will do soon. recently one of the screws in the reedblock fell out and left a circle dent in the end of my piston/cylinder head. thats y i think it is related to something down that area because the bike stopped working because the piston couldnt go all the way down , so it wouldnt turn over. thanks.
You should replace the piston you might have to replace the kit, could be a full rebuild make sure there is no filings or anything in the crank.
rod bearing is normally called the little end,its more likely to rattle not knock the bottom of con rod is the big end ,if thats on way out it will knock,the main bearings round it will rumble,if you dropped a screw in it could well be damaged to big end,try a thin magnet down inside crankcase
thanks for the info. there are two sounds. 1 rattling/hissing sound and 1 sound that sounds like if u was to put a screw in a can and shook it. we only did find half that screw , the other half i dont know where it is but ive looked in the crank and cant seen to see it anywhere. how can i tell if the big end is broke? thanks
i just hope its nothing too expensive as im only 16 and havent got a job and am getting 10€ a week :/
