fuel or spark?

[Pbassred]

VFR800 Vtec 2011

At start up it coughs and runs rough. It needs a little throttle to even keep running. After 30 seconds it will run independently @9500RPM and as it gets a little heat on it clears itself an runs at 2000, which is the intended cold RPM setting. from 35°C to 50°C it gradually winds down and ticks over at 1200°C sweet as a nut.

Other than the some coughing at 3000 (filtering) and sometimes a flat spot accelerating gently through 3000, it runs ok.

I've had the VFR for about 6 weeks or 2000miles. This started about 3 weeks ago. I ran some fuel system cleaner through it and it seems better but started again. It could be electrical but why only at cold? Full disclaimer:- I did the PAIR and flapper mod a couple of weeks ago and I could easily undo then but I don't see what difference they would make to start-up.

Any ideas?

[dern]

Undo the changes you made, disconnect the battery for an hour or so and see if the problem persists. Given the coincidence in timing you should discount it however unlikely.

[ThePhatomfart]

VFR800 Vtec 2011

At start up it coughs and runs rough. It needs a little throttle to even keep running. After 30 seconds it will run independently @9500RPM and as it gets a little heat on it clears itself an runs at 2000, which is the intended cold RPM setting. from 35°C to 50°C it gradually winds down and ticks over at 1200°C sweet as a nut.

Other than the some coughing at 3000 (filtering) and sometimes a flat spot accelerating gently through 3000, it runs ok.

I've had the VFR for about 6 weeks or 2000miles. This started about 3 weeks ago. I ran some fuel system cleaner through it and it seems better but started again. It could be electrical but why only at cold? Full disclaimer:- I did the PAIR and flapper mod a couple of weeks ago and I could easily undo then but I don't see what difference they would make to start-up.

Any ideas?

 

Did you disturb any part of the Idle Control Unit (Wax Unit)

[Pbassred]

Did you disturb any part of the Idle Control Unit (Wax Unit)

Where is that?

[Stu]

Did you disturb any part of the Idle Control Unit (Wax Unit)

Where is that?

 

attached to the throttle bodies and has two water pipes to it

did you mess about with the coolant? as it works off the coolant and if there is an air lock this could affect it

[ThePhatomfart]

Here

https://www.bike-parts-honda.com/honda-motorcycle/800-MOTO/VFR/2011/VFR800A9/Engine/THROTTLE-BODY-ASSY-/13MCW601/E__1700/1/13806

and

[Ian Frog]

Before you go all complex have you got access to a known good battery?

I had an annoying intermittent misfire and erratic idle on the ZRX particularly when cold.

Spent a lot of time cleaning carbs and checking stuff.

Borrowed battery from another bike and all perfect Grrr!

New battery now installed and all is good.

Cheers

Ian

[Pbassred]

I tried disconnecting the battery to reset the ECU, but that wasn't it. I reversed the PAIR and flapper valve mods and It thing that got it. It starts unaided, but its supposed to idle at 2000RPM until it warms up and settles to 1200. Its more like 2400. I didn't notice that before.

When the weather improves I might see which of the mods makes the difference. Its odd that other people haven't see this though.

[ThePhatomfart]

Have you tried unplugging the MAP sensor , ( for start up purposes only) to see if it settles.

But dont touch the Throttle