RMZ250 2017 headache

MX690
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MX690 10/2/2023 1:09am
10/2/2023 1:09am
wsc96 wrote:

Mentioned earlier, but try running it with the fuel cap off yet?

Yep Could easily be a something as simple as a  blocked breather hose.

2
SCAM124
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SCAM124 10/2/2023 5:19am
10/2/2023 5:19am

I struggled with my son's 2017 RMZ250 earlier this year.  I also went down the rabbit hole in the forums because I could NOT figure this thing out. I tore into this thing checking everything I knew. Fuel breather, fuel pump pressure, volume, electrical harness connections.  Everything.  Been there, done that over the years and this thing was pissing me off.

I had 2 things going on I think were separate issues but I was chasing them as a single problem.  The bike would run intermittently ok one day, not good the next.  On occasion would start, but pop and sputter.  Then no start.  Even dragging it down the road, nothing.

1) Fuel contamination - He had an aftermarket fuel cap that had a spongy rubber gasket in it.  It was cracking and dropping bits of material into the fuel tank.  I disassembled the fuel pump (against the service manual's recommendation) and also cleaned the injector and it started ok. Seemed the issue was solved!  Nope!  After a practice session at the track, bogging and reluctant to start.

2) Bad ECU - I walked the service manual diagnostic flowchart.  Got to the bottom of the flowchart.  Faulty ECU??  "No way". I thought...  Never had one go bad, plus it just started and ran the other day right? I eBay'd a used unit on a chance.  Bam...started right up.  Been running good ever since.  

I was chasing a fuel issue the whole time thinking it was somehow related to the bits I found in the fuel. It   It may have never actually been fuel related.  Coulda been that damn ECU working, then not working intermittently.  I'd suggest to walk the troubleshooting flowchart for electrical.  The used ECU was $230.  

Good luck.

2
r.rodriguez
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r.rodriguez 10/2/2023 6:51pm
10/2/2023 6:51pm

I will check when I go back to shop later today. 

IDK if it matters or not but could 90 PSI be too high for the fuel pump? It should be around 45-50 at most.right? I do not know what this would affect but can it cause the CDI/ecu to trigger a non running condition? 

r.rodriguez
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r.rodriguez 10/2/2023 6:55pm
10/2/2023 6:55pm
SCAM124 wrote:
I struggled with my son's 2017 RMZ250 earlier this year.  I also went down the rabbit hole in the forums because I could NOT figure this...

I struggled with my son's 2017 RMZ250 earlier this year.  I also went down the rabbit hole in the forums because I could NOT figure this thing out. I tore into this thing checking everything I knew. Fuel breather, fuel pump pressure, volume, electrical harness connections.  Everything.  Been there, done that over the years and this thing was pissing me off.

I had 2 things going on I think were separate issues but I was chasing them as a single problem.  The bike would run intermittently ok one day, not good the next.  On occasion would start, but pop and sputter.  Then no start.  Even dragging it down the road, nothing.

1) Fuel contamination - He had an aftermarket fuel cap that had a spongy rubber gasket in it.  It was cracking and dropping bits of material into the fuel tank.  I disassembled the fuel pump (against the service manual's recommendation) and also cleaned the injector and it started ok. Seemed the issue was solved!  Nope!  After a practice session at the track, bogging and reluctant to start.

2) Bad ECU - I walked the service manual diagnostic flowchart.  Got to the bottom of the flowchart.  Faulty ECU??  "No way". I thought...  Never had one go bad, plus it just started and ran the other day right? I eBay'd a used unit on a chance.  Bam...started right up.  Been running good ever since.  

I was chasing a fuel issue the whole time thinking it was somehow related to the bits I found in the fuel. It   It may have never actually been fuel related.  Coulda been that damn ECU working, then not working intermittently.  I'd suggest to walk the troubleshooting flowchart for electrical.  The used ECU was $230.  

Good luck.

thank you for this info brother. ECUs are quite expensive we will try other stuff first before proceeding to buying it. 

The Shop

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SCAM124
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SCAM124 10/3/2023 4:33am
10/3/2023 4:33am
r.rodriguez wrote:
I will check when I go back to shop later today.  IDK if it matters or not but could 90 PSI be too high for the...

I will check when I go back to shop later today. 

IDK if it matters or not but could 90 PSI be too high for the fuel pump? It should be around 45-50 at most.right? I do not know what this would affect but can it cause the CDI/ecu to trigger a non running condition? 

Fuel pressure is regulated at 42psi. 90 is way too high.

image-20231003073327-1

Do you have a service manual?  

vdrsnk04
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vdrsnk04 10/3/2023 6:47am
10/3/2023 6:47am

I didn’t see it mentioned in here so I’ll say the obvious. 
 

do you have a full tank of fresh fuel in it?

 

reason I ask, I had a friend and his dad once that couldn’t get his bike running for more then a few seconds like yours, they were pulling it around trying to pull start it too. Ended up just the tank was empty lol.

1
Airjordan
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Airjordan 10/4/2023 7:25am
10/4/2023 7:25am

Congrats on nailing it down to a fuel problem 90 psi is no bueno. Fuel regulators and fuel restrictions are the most common causes of high fuel pressure. If you know anyone with the same generation rmz try swapping tanks this way if it doesn't change your situation you can rule that part out and if it fixes it bingo this way your not throwing $ around playing the guessing game.

r.rodriguez
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r.rodriguez 10/11/2023 3:59am
10/11/2023 3:59am

alrighty then, brothers. thank you so much for all your replies. effing head ache gone.

problem with spark :  i bought a new stator/pulser package. installed it to no avail; tried using same stock stator with the new pulser(only) - works like a charm.

gas problem: we removed the fuel filter just for a test, it runs good, so I bought new fuel pump + filter package - works great.

however, we haven't tried doing laps in our local track yet because of bad weather. I will let you guys know when we do.

once more, much appreciation for the replies. dirtbike brothers are solid!

 

7
motoarmageddon 10/13/2023 9:40pm
10/13/2023 9:40pm

the magnet in the magneto rotor could be broken up or gone bad.  have seen this in an rm-z450

burn1986
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burn1986 10/20/2023 8:42pm
10/20/2023 8:42pm
r.rodriguez wrote:
alrighty then, brothers. thank you so much for all your replies. effing head ache gone. problem with spark :  i bought a new stator/pulser package. installed...

alrighty then, brothers. thank you so much for all your replies. effing head ache gone.

problem with spark :  i bought a new stator/pulser package. installed it to no avail; tried using same stock stator with the new pulser(only) - works like a charm.

gas problem: we removed the fuel filter just for a test, it runs good, so I bought new fuel pump + filter package - works great.

however, we haven't tried doing laps in our local track yet because of bad weather. I will let you guys know when we do.

once more, much appreciation for the replies. dirtbike brothers are solid!

 

Any word, Thanks 

r.rodriguez
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r.rodriguez 10/23/2023 3:21am
10/23/2023 3:21am
r.rodriguez wrote:
alrighty then, brothers. thank you so much for all your replies. effing head ache gone. problem with spark :  i bought a new stator/pulser package. installed...

alrighty then, brothers. thank you so much for all your replies. effing head ache gone.

problem with spark :  i bought a new stator/pulser package. installed it to no avail; tried using same stock stator with the new pulser(only) - works like a charm.

gas problem: we removed the fuel filter just for a test, it runs good, so I bought new fuel pump + filter package - works great.

however, we haven't tried doing laps in our local track yet because of bad weather. I will let you guys know when we do.

once more, much appreciation for the replies. dirtbike brothers are solid!

 

burn1986 wrote:

Any word, Thanks 

wassup, brother! Our bike now runs good.  2 kicks even when hot as long as you get the proper timing. 

We think what really helped was the new pulser, ultrasonic cleaning of injector, and changed new fuel pump+filter.

Much appreciation to all the replies.

Stay safe out there in the tracks and trails brothers! 

3

Pit Row

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