I have a 1980 rm125 it does not start it just back fires
I just did a top end rebuild on it I change the carb I put a new cdi on it and a new coil whenever I push start it cuts off right away and when I kick start it just back fires and I threw gas inside the intake and it still didn't start and the bike has spark
Motorcycles - GAS
Answers & Comments
Hey Guys, I noticed that nobody asked the obvious. Since you just rebuilt it, did you remember to put the reed valve in correctly? It is actually impossible for a two stroke to "backfire" with a functioning reed valve installed. Hope this helps.
classic symptoms on a sharp ported 2 stroke engine when its low on compression.
if he had said it was chuffing or pre-igniting i would have given him the advice you did. He said backfiring though, which is when the exhaust is ported back though the carb. I answer the best i can with the info given, which usually isnt much on these posts. I had a bike i had forgotten to put the reed valve in and the thing backfired like mad, hence the advice i gave.
Definitely piston & or rings problem, thereis a dot or llittle circle stamped on rings they must be facing up & arrow on piston crown should be facing exhaust
the arrow doenst always point to the exhaust though,its more about the ring pegs being on the inlet side of the barrel.
i took a piston out of an rs 50 last week and it was fitted by another shop with the arrow facing forwards and i took the piston out and the rings dropped off as they had opened into the exhaust port because it was fitted the wrong way around,i never look at the arrow just the ring pegs as they line up with the bridges in between the inlet ports.Now its not common for it to be that way around but its not the first time i have seen in in 22 years of doing it for a living.
Usually a 2 stroke will chuff/backfire out of the exhaust if it low on compression, did you put the rings in the right grooves and up the right way and is the piston in the right way around as there is a front and back ,the ring pegs are supposed to face the inlet side of the barrel.
ps i know someone who is selling a nearly finished restoration on a rm125 he dontt wanna lot for it !
As far as I know diamond pistons are an American company that make custom pistons for cars? Maybe the owner had one made for some odd reason for his bike anyway, where in the world is this rm for sale? I am currently doing business in turkey, could the bike be shipped & is there anyway of a private chat so I can give you my contact details adam?