Stalling from cold starts

[wil55n]

Just curious if your RCs always stall when starting from cold? Mine always follows the same pattern:

1. Start engine, runs fine
2. After 30 seconds, engine stalls.
3. Start again, struggles to start but eventually gets there.
4. After a minute the engine is still too cold (it will stall if I try and ride)
5. After about 3 minutes the engine temp is in the middle and I'm good to go.

 

[oz!]

Have the same issue

Sent from my LG-K373 using Tapatalk

 

[Treachery]

Similar. It seems to run if I pretty much get on it and go as soon as it starts. Otherwise, it stalls when I put it in gear, followed by the hard start. It doesn't take the three minutes to get going though. This appears to be integral to the bike, as the installation of a PCV did not eliminate the behavior.

 

[Maddog Reynolds]

When it stalls in gear, have you just started to open the throttle a bit, or blipped it? That's when mine stalls.

Mine will idle from cold until warm and it's fine going into gear, but as I open the throttle I have to let revs rise to 4,000 or more before I start to release the clutch at all.

 

[Treachery]

Mine's not that severe. I've never let it idle that long. If it dies, after I get it re-started, I do give it a little more of a goose, and I get going. It hasn't (AFAIK) croaked after getting underway.

 

[Maddog Reynolds]

I think we are seeing different variations on the same problem--a tendency to run too rich on part throttle when cold.

I have never used a PC5--if I were to fit one, would I be able to remap the cold/part throttle values for the problem rev range (2,000 to 4,000 rpm) used open loop, without altering the rest of the map?

Mine's a road bike, so I want smooth warm-up, economy on part throttle (14.7:1 is fine) but then I also want to be able to adjust the top end if I change the exhaust or inlet.

 

[shreeshar7]

I had this issue earlier on my 2015 Rc390.
Until the engine warms up if I slowly let go of clutch and slightly open the throttle it would stall.
This would also happen in situations like slowing down at a speed braker and again using clutch in first or second gear with slight throttle.

Once engine was warm the issue would dissappear.

They replaced the entire throttlebody and problem was still there..

Then,the throttlebody sensors as well as injector was replaced,it didn't seem to help much.

Finally they took off the valve cover and shims were changed and adjustment was done, now it doesn't stall anymore, right after starting it I can pull away just with the clutch. Seemed like the valves were slightly on the tighter side.

I also suggest you to clean the throttlebody once during the process.