The Honda NSR125 doesn't have two cylinders - it has only one cylinder. If you have an NSR125 and it sounds like that, then you're "four-stroking" in the middle of the RPM range. "Four-stroking" (not firing exactly 50% of the time) is caused by too rich a mixture, which tells me that either your air intake has a problem or your carburetor wants more attention. If you only cleaned it by pouring carburetor & choke cleaner into the fuel tank, that's probably not enough - you'll probably need to disassemble the entire carburetor and run carburetor cleaner spray through every port & jet or put it in a dip tank until it's dead clean inside.
Since it seems to clear up at higher RPMs, it's probably not your intake - that's just get worse & worse at higher RPMs. I've gotta' say I believe your carburetor's still not clean inside.
Since it's running rich below 4KRPM, it should hurt anything except your pride & your bike's performance. It should NOT seize the engine - that'd happen if your fuel mix was too LEAN, but yours is too RICH.
Nov 05, 2013 |
Honda NSR 125 Motorcycles