Honda 420 intermittent fault

[Mully 19]

Hi everyone

A friend asked me to look at his 08 420 manual shift. Intermittent fault is : when he stops bike doing some spot spraying for example, bike left ticking over and in gear and goes to move again the bike dies as if it under load or can’t get fuel sometimes it splutters when driving slowly. He bought it to local dealer number 1 and they put a new fuel pump but fault remained he bought it to local dealer number 2 and they said/put a new loom in it and fault returned. 
Also by accident he discovered that if he puts bike into reverse it’s ok and then ok going forward so that is what he has been doing as the problem occurs .

Its a strange one for me . Thanks for looking any help would be greatly appreciated. 

[shadetree 5,977]

18 minutes ago, Mully said:

Hi everyone

A friend asked me to look at his 08 420 manual shift. Intermittent fault is : when he stops bike doing some spot spraying for example, bike left ticking over and in gear and goes to move again the bike dies as if it under load or can’t get fuel sometimes it splutters when driving slowly. He bought it to local dealer number 1 and they put a new fuel pump but fault remained he bought it to local dealer number 2 and they said/put a new loom in it and fault returned. 
Also by accident he discovered that if he puts bike into reverse it’s ok and then ok going forward so that is what he has been doing as the problem occurs .

Its a strange one for me . Thanks for looking any help would be greatly appreciated. 

going out on a limb here, my mind tells me dirty fuel injector ?, or maybe not enough fuel reaching throttle body ?. yes..i read where you said the fuel pump was replaced ^^ , but this does not mean fuel is reaching the pump, then to throttle body. also, i do not recall if these models have a bank angle sensor or not ?, its posb it is bad if this does in fact have a bank angle sensor. i still think this is a fuel delivery issue myself. somewhere on this atv is a fuel pump relay, it too can be bad.

[Mully 19]

Lots to think about, thanks Shadetree. I’m going to investigate if/where fuel pump relay might be as it’s probably easiest to replace and best place to start. Regarding the injector is there much to cleaning/ inspecting them and how could I go about testing one?

[toodeep 1,760]

Fuel pump relay is back by the battery at the bottom of the box (kind of under the fuse panel). I relocate all of mine just so they aren't sitting down in the debris that collects there. That was going to be one of my suggestions as long as the local dealers was using original honda parts when they replaced the fuel pump (it should be the complete sub fuel tank assembly and not just a pump even though that's what people will call it). Some dealers will use aftermarket stuff  is the reason I mention that.