Hi so ideas needed about my semi dead Honda sh125 injected. It starts at button. When not under load revs all the way to rev limiter with no odd sounds, spluttering or vibration. When under load can gently get to about 15mph (20 if have very long, flat road). Above that it starts vibrating (miss firing), choking, banging, popping and stops. It seems much better when cold then hot. So far changed then tested: + Clutch (plus rollers and belt as needed it) + fuel pump + air filter + injectors + ht lead + cdi unit (and spark plug) It has oil and not sure it was ever starved of it. No change any ideas Wtf is wrong with it? Mechanic has no idea he said we should now try stator and if not engine is gone. Any idea Wtf is wrong with it, does it have ecu?
where is the fuel pressure regulator on pump or fuel rail possibly low pressure. also disconnect exhaust and re try, this fault sounds reet familiar.
Will check fuel pressure regulator. Disconnecting exhaust what purpose it has, what will I learn from it?
It was fine a month ago. Then it went pop so I retired it for 2 weeks and now 2 more weeks with mechanic. Peter feel free to come along next week and solve the riddle we know you like to Obviously after 2 months at full throttle
Ok so lets be honest here and sensible............................................ no I really mean it. When you say it went pop can you elaborate a bit more please Lucas? Did it seize? just die, run out of fuel? or what? Did you accidently put diesel in it? Does it start well? any noises like rumbling from the mains? It does have an ECU as it is fuel injected, so it has all the same sensors that a bigger bike has so we need to see if one of these has failed, what I need to identify is that is it mechanically broken ie- damaged piston/rings or bearings or is it an electrical fault.
Ok on day of failure it was sluggish barely doing 50 mph. I was thinking rear brake is seazing (that is how it felt especially that rear tyre was changed 2 days before). About 1 mile from work it went from barely 50 to above. Until you reach the 15-20 mph mark it sounds normal, healthy, purring like kitten on steroids. From about 15-20 it starts feeling rattly similar to piston slap on 2V Ducati. If you keep throttle there it will stall few seconds later (despite it loosing power ie dropping Revs and speed). If you open more it will pop via airbox and stall. If you shut the throttle slightly engine will recover and will work normal again so it is clearly throttle opening related. Especially that if you try and set off full throttle it will stall asap. To get to 15mph you have to be gentle. It starts on the button. Revs all way till max with no odd sounds. Has oil, petrol (not diesel unless there was diesel in petrol line), new air filter, new rollers, now new clutch, new belt, new spark plug.
