Jump to content

Starting Procedure - '15 RT


TexasMule

Recommended Posts

I sold my F850GSA to purchase the '15RT and thought I was done with this odd starting procedure in cold weather.

 

The RT fails to start on the first fire up of the day, but I let it turn over just a couple times, and then hit the starter again

and she fires right up, instantaneously.   My wife's F750GS  and my GSA did this same crap in cold weather.

 

Has anyone successfully explained why these bikes are so difficult to start first time in cold weather.  My 2004 R1150RTstarted

(albeit complaining) in 14F in Flagstaff, and my 2008 R12RT NEVER failed to start immediately.  Is it because of all the electronics?

 

Just wondering.  It's not that big of a deal, but I would think by 2015 BMW would have the starting process down to a science.

 

I'm thinking about putting a booster plug on the bike to spoof the ECU into thinking it's cooler than it really is to enrich the fuel mixture.

Worked really well on my '04, and seemed to help my '08 too. 

 

Any thoughts?

 

 

Link to comment

My 2015 RT does this too, sometimes even at temps as warm as 60-70F.  My solution is that if it does not immediately fire, I just release and hit the start button again and it always fires right up. 

 

Many claim this is cured by making sure the cam timing is spot on.   Recently another member posted that in the OM it instructs you on cold days to disengage the clutch and open the throttle a little on start-up.  Sheepishly I admit I had not read this page in the OM, so next spring I'll give the cold weather start procedure a try.

 

image.png.0e7b027a1c037f4bc04f9262b177c3a1.png

 

 

Link to comment
On 12/21/2020 at 6:57 PM, TexasMule said:

The RT fails to start on the first fire up of the day, but I let it turn over just a couple times, and then hit the starter again

and she fires right up, instantaneously.   My wife's F750GS  and my GSA did this same crap in cold weather.

 

Has anyone successfully explained why these bikes are so difficult to start first time in cold weather.  My 2004 R1150RTstarted

(albeit complaining) in 14F in Flagstaff, and my 2008 R12RT NEVER failed to start immediately.  Is it because of all the electronics?

 

Morning  TexasMule

 

Your 750 & 850 both have a spring loaded compression release on the cam,  this allows the starter to get the engine spinning fast enough to start before the compression release kicks in & allows enough starting compression.  If the engine is real cold (especially with thicker viscosity oil) it doesn't spin over quite fast enough to allow the compression release to allow full compression. Usually giving it just a bit of throttle twist during the engine cranking will add just enough extra fuel to fire it off even with the lowered compression. 

 

My 800gs starts super easy down to about 25°f, but below that first start in the morning usually needs about 1/8 throttle to fire off on first engine cranking. 

 

Your old 1150  didn't have (or need) a compression release  as it had a gear reduction starter, plus your old 1150 didn't have that idle air control that computer controlled the idle RPM. But you did need to (or should anyhow) disengage the clutch (hold clutch lever in)  to take the transmission drag off the engine during cold cranking.

 

On your 2015RT in cold weather, first try turning the key ON then give it a few extra seconds before cranking to allow the fueling computer to fully home then re-set the idle control.

Then  try holding the throttle at about 1/8 open, THEN try starting the engine.

If still no start on the first try then look at the  cam timing or look for a battery that is just a little too weak to spin the engine fast enough to get the compression release to kick in.   

 

 

 

 

Link to comment

Yes it is now written in the manuals to give the bike a bit of fuel for starting.

 

I never have here in PA. 

 

And mostly since my first FI anything I was told to never give it gas on a start.   

 

It appears the new instructions in the manuals tell you to give it a bit of throttle on start.

 

I will say if your battery is good your problem could be your cam position sensor is not set correctly.

 

I have set at least 5 bikes that show a immediate improvement in start from adjusting this in a cam timing check.

 

If you were near me we would get it done no problem.   I would use the throttle to see if that does it but I would want to check the sensor and cam alignment.

camshaft+sensor.jpg

 

  • Like 1
Link to comment

My '16 GSA was fine at first, then developed the no-start-on-first-attempt problem, but somewhere around 5,000 miles I realized it wasn't doing it any more - it's like hiccups, you have them then notice you don't but can't tell when they stopped.  After that it never returned, and I put a lot of miles on the bike. Never did the cam alignment thing.

 

I will say that even when I went out below freezing, the bike had been in an attached garage (40* maybe?) and if I stopped it never had time to completely cool down.

Link to comment

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...