Hello all,

I have a new 2021 950 I picked up in February. Riding season has started here in Maine and I am in the break in period. About 30 miles into the break in I have had an annoying problem come up. If you hold the throttle at about half for a minute or so the throttle cuts out for a bout a second and comes back. It happens around 4500 to 5000 rpm and it doesn't matter whether you are in L or H 2wd or 4wd. Some times it happens once other times it happens 5 or 6 times in quick succession.  It idles fine and accelerates fine. The temperature is always good. My neighbor took a ride with me last night and he noticed it as well. It has been happening for the last two days now.

Any thoguhts?

So I was at my local club meeting last night and there is a gentlemen in my town who bought a 950 a year ago from the same dealer with the exact same issue. This dealer replaced a bunch of parts, spark plugs, TPS, gas pedal and I believe he said the ECU. Not only did this not fix the issue it has seemed to have gotten worse.

Ironically we are both dropping off our machines to a different dealer on the same day for the same problem.

My machine has about 3700 miles on it.  I started having intermittent loss of power in the 3500 - 4250 rpm range.  Mine symptoms started about 2 months ago and only occur after the machine has been driving for about 15 minutes.  It will hesitate slightly, experience momentary loss of power, and maybe a few misfires.  This only happens at steady throttle.  As soon as I get up to about 5k rpm, the symptoms stop and the machine runs smoothly. 

Another person on FB was quoting the MSC guy Joel Crane who suggested changing the brake switch (5HY0-080010).  Joel Crane felt that the brake switch is telling the ECU to cut power. I'm not convinced it would be that part since it is a simple gate and if it were bad, then it would also tell the brake lights to turn on.  I do not experience any brake flashes and a couple other people I talked too do not experience the flashes either.  But the switch is relatively inexpensive, so I'll give it a try. 

After replacing the switch, I'll test it.  I'm also considering checking the valve gap.  At 3,700 miles, its time for that job to be completed.

WhiteRabbit,

Thank you for pointing me in this direction. This morning I tracked down the connector that leads to the brake pedal switch. It is tucked up under and behind the left headlight. I managed to squeeze my hands in and disconnect the switch. I took it out for my test ride which is about 6 miles and had no ignition cut outs.

So far so good. I will drive it again to check it out further.

Thanks.

Another update.

I went for a second ride with the same trails where I noticed this problem the first time. No issues. I then went to another section of the trails where I had the problem about 3 miles away and repeated my drive. Nothing noticed.

it looks like the brake pedal switch is causing the issue. Now the real question. What is causing the witch to cut out.

Went for another ride today and this was a false lead. The sudden throttle cut didn't come back but now the throttle is suffering an issue.

When you hold the throttle at a steady position at times the engine will lose power and then gradually come back. I did notice as the ride got longer the problem got worse. I also noticed that when you were on a banked trail, especially to the right, the problem got worse.

Tank pickup issue, tank need a baffle, heat soaking of the system, fuel pressure?

[2015 Z Force 800 53/Trail EPS]

Take it in!

I had the same or similar problem with my Z950, had the brake switch replaced under warranty,
Now it is running just fine. Chances are your problem is the brake switch.

I will be curious to see.

It is at the dealership and they have replaced the switch. The gentlemen in the club with the same issue has already had this replaced with no improvement.

I actually disconnected this switch with no change to the problem.

The dealer said the only way they could reproduce the problem was doing a brake stand. If you push the brake pedal down it takes a good half inch or so of travel before it switches. I even tried while on the trail while riding to press the brake pedal and see what happens and there was no issue.

The saga continues.

To keep everyone up to date. The 950 has been to the dealership and back. I am trying to document further what is going on with lots of video. I did find one thing. The other gentlemen's 950 has been fixed so I did a similar check and found that the plug for the fuel pump had so little mechanical resistance it felt like the pins were barely touching. I cleaned everything up and gave the pins a little more friction. Since then the notchy-ness / non-linearness of the throttle in sport mode has gone away. I am still having a slight cut out issue. It goes back to the dealership for service next Saturday.

I did have one problem twice this weekend where the unit wouldn't even start or the fuel pump turn on. Come to find out if you jiggled the shift lever it would cut in and out. I wonder if the shift lever, shift detent and shift sensor need adjusting and this may be causing some of my issues.

We shall see.