2017 RMZ450 Low Hour motor issues?? Edit: Found the problem. Cracked Piston

mattyhamz2
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mattyhamz2
Edited Date/Time 1/24/2019 9:39pm
Anyone had or heard of any issues with the motors on 2017 RMZ450's?? Particularly with low hours? Like 20-25 hours
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Rotaholic
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Rotaholic 1/23/2019 1:16pm
1/23/2019 1:16pm
They're pretty bulletproof but with so many parts there is always room for something to just fail. What's the issue?
mattyhamz2
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mattyhamz2 1/23/2019 1:22pm
1/23/2019 1:22pm
Rotaholic wrote:
They're pretty bulletproof but with so many parts there is always room for something to just fail. What's the issue?
We've never had any issues until now with any of the other RMZ's we've had. Friend of mine came out of a corner, got on the gas, bike bogged and died. Bike has no more than 25 hours with oil, oil filter and air filter changed every other ride. He said it feels like it lost quite a bit of compression and when he tried to start it up it spit oil from the over flow. Weird deal. It hasn't been ridden hard or at high RPM's either.

I saw your post from a little over a year ago about Darryl Hurley having some motors for these bikes. Any chance he might still have some just in case?
mattyhamz2
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mattyhamz2 1/23/2019 1:23pm
1/23/2019 1:23pm
We've had the same experience with ours. Never had issues. This seemed really weird.
Rotaholic
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Rotaholic 1/23/2019 3:03pm
1/23/2019 3:03pm
Rotaholic wrote:
They're pretty bulletproof but with so many parts there is always room for something to just fail. What's the issue?
mattyhamz2 wrote:
We've never had any issues until now with any of the other RMZ's we've had. Friend of mine came out of a corner, got on the...
We've never had any issues until now with any of the other RMZ's we've had. Friend of mine came out of a corner, got on the gas, bike bogged and died. Bike has no more than 25 hours with oil, oil filter and air filter changed every other ride. He said it feels like it lost quite a bit of compression and when he tried to start it up it spit oil from the over flow. Weird deal. It hasn't been ridden hard or at high RPM's either.

I saw your post from a little over a year ago about Darryl Hurley having some motors for these bikes. Any chance he might still have some just in case?
Definitely give Darryl a call, he will look after you for sure.

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mattyhamz2
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mattyhamz2 1/23/2019 3:08pm
1/23/2019 3:08pm
Rotaholic wrote:
They're pretty bulletproof but with so many parts there is always room for something to just fail. What's the issue?
mattyhamz2 wrote:
We've never had any issues until now with any of the other RMZ's we've had. Friend of mine came out of a corner, got on the...
We've never had any issues until now with any of the other RMZ's we've had. Friend of mine came out of a corner, got on the gas, bike bogged and died. Bike has no more than 25 hours with oil, oil filter and air filter changed every other ride. He said it feels like it lost quite a bit of compression and when he tried to start it up it spit oil from the over flow. Weird deal. It hasn't been ridden hard or at high RPM's either.

I saw your post from a little over a year ago about Darryl Hurley having some motors for these bikes. Any chance he might still have some just in case?
Rotaholic wrote:
Definitely give Darryl a call, he will look after you for sure.
Do you know where I can find his contact info?
Underground 1/23/2019 6:21pm
1/23/2019 6:21pm
Drain and measure the quantity of engine oil and check for foreign particles in the oil and filter. You may have mistakenly under drained or over filled. Always check the easy stuff first.
tylermx967
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tylermx967 1/23/2019 6:42pm
1/23/2019 6:42pm
MY DAD GOTS THE 2012 SUSZUKI AND HE DIND EVER HAVE PROBLEM WITH THE MOTOR DID U TAKE IT TO THE MUD BOG???
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mattyhamz2
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mattyhamz2 1/23/2019 9:11pm
1/23/2019 9:11pm
Underground wrote:
Drain and measure the quantity of engine oil and check for foreign particles in the oil and filter. You may have mistakenly under drained or over...
Drain and measure the quantity of engine oil and check for foreign particles in the oil and filter. You may have mistakenly under drained or over filled. Always check the easy stuff first.
All oil and filter was good. No debris and oil level was perfect. Talked to him a little bit ago and he’s not getting spark. He’s going to disconnect the kill switch and go from there before pulling the motor apart. Also checked and no loss of compression. It was in his head i guess lol.
Rotaholic
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Rotaholic 1/23/2019 9:36pm
1/23/2019 9:36pm
Definitely check the plug from the fuel pump to the harness, they corrode and always fail.
mattyhamz2
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mattyhamz2 1/24/2019 11:51am
1/24/2019 11:51am
needforspeed78 wrote:
Cracked piston is my guess, we had few of those in 2015-2017 bikes at low hours.
What did it do before you took it apart? Like symptoms that you had?
DC41
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DC41 1/24/2019 12:00pm
1/24/2019 12:00pm
I also had a cracked piston with my 2016 rm-z 450 when it had only 12 hours on it.. the bike just quit running like it would when you run out of fuel...
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mattyhamz2 1/24/2019 12:02pm
1/24/2019 12:02pm
DC41 wrote:
I also had a cracked piston with my 2016 rm-z 450 when it had only 12 hours on it.. the bike just quit running like it...
I also had a cracked piston with my 2016 rm-z 450 when it had only 12 hours on it.. the bike just quit running like it would when you run out of fuel...
Did it backfire at all when you tried kicking it over?
DC41
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DC41 1/24/2019 12:04pm
1/24/2019 12:04pm
mattyhamz2 wrote:
Did it backfire at all when you tried kicking it over?
No it didn’t do anything when you kicked it, it just died..
DC41
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DC41 1/24/2019 12:08pm
1/24/2019 12:08pm
This is a picture of the cracked piston in my RM-Z.
mattyhamz2
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mattyhamz2 1/24/2019 12:14pm
1/24/2019 12:14pm
mattyhamz2 wrote:
Did it backfire at all when you tried kicking it over?
DC41 wrote:
No it didn’t do anything when you kicked it, it just died..
We've tried kicking it over a few times and it's popped(backfired) twice out of 20+ kicks but it doesn't want to fire at all.
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colvin227 1/24/2019 12:18pm
1/24/2019 12:18pm Edited Date/Time 1/24/2019 12:20pm
DC41 wrote:
I also had a cracked piston with my 2016 rm-z 450 when it had only 12 hours on it.. the bike just quit running like it...
I also had a cracked piston with my 2016 rm-z 450 when it had only 12 hours on it.. the bike just quit running like it would when you run out of fuel...
mattyhamz2 wrote:
Did it backfire at all when you tried kicking it over?
You had said it had passed a compression test right? Surely a cracked piston would show up on a compression check or a leak down test. Could always pull the plug and boroscope the top of the piston to see it’s condition but it sounds like an electrical issue. You stated it was not getting spark so I’d start down that route. ECU, coil, stator all electrical connections......

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mattyhamz2
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mattyhamz2 1/24/2019 12:20pm
1/24/2019 12:20pm
DC41 wrote:
I also had a cracked piston with my 2016 rm-z 450 when it had only 12 hours on it.. the bike just quit running like it...
I also had a cracked piston with my 2016 rm-z 450 when it had only 12 hours on it.. the bike just quit running like it would when you run out of fuel...
mattyhamz2 wrote:
Did it backfire at all when you tried kicking it over?
colvin227 wrote:
You had said it had passed a compression test right? Surely a cracked piston would show up on a compression check or a leak down test...
You had said it had passed a compression test right? Surely a cracked piston would show up on a compression check or a leak down test. Could always pull the plug and boroscope the top of the piston to see it’s condition but it sounds like an electrical issue. You stated it was not getting spark so I’d start down that route. ECU, coil, stator all electrical connections......
Should have updated more. He was able to get spark last night and just for safe measure put in a new plug this morning and still getting strong spark. Plan is to check the injector next but wanted to hear more info about the guys with the cracked pistons.
Polishhammer 1/24/2019 12:26pm
1/24/2019 12:26pm
I had a 2012 that had spark and would just pop when kicked. It turned out the flywheel went bad. Weird
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colvin227 1/24/2019 12:34pm
1/24/2019 12:34pm Edited Date/Time 1/24/2019 12:36pm
mattyhamz2 wrote:
Did it backfire at all when you tried kicking it over?
colvin227 wrote:
You had said it had passed a compression test right? Surely a cracked piston would show up on a compression check or a leak down test...
You had said it had passed a compression test right? Surely a cracked piston would show up on a compression check or a leak down test. Could always pull the plug and boroscope the top of the piston to see it’s condition but it sounds like an electrical issue. You stated it was not getting spark so I’d start down that route. ECU, coil, stator all electrical connections......
mattyhamz2 wrote:
Should have updated more. He was able to get spark last night and just for safe measure put in a new plug this morning and still...
Should have updated more. He was able to get spark last night and just for safe measure put in a new plug this morning and still getting strong spark. Plan is to check the injector next but wanted to hear more info about the guys with the cracked pistons.
Yeah on to the fuel I’d say......you aren’t getting any ECU diagnostic faults? Evident of a light on the holeshot map switch? To rule out the piston thing, like I’ve said running a small diameter scope down the plug hole should tell you all you need. Some auto parts places have them to rent out if need be, or pulling the cylinder isn’t too in-depth for the average wrench. If it passed a compression check, and if it would pass a leak down test then I’d doubt the cracked piston theory. But never know and I guess peice of mind is to just have a look.
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mattyhamz2 1/24/2019 12:37pm
1/24/2019 12:37pm
colvin227 wrote:
You had said it had passed a compression test right? Surely a cracked piston would show up on a compression check or a leak down test...
You had said it had passed a compression test right? Surely a cracked piston would show up on a compression check or a leak down test. Could always pull the plug and boroscope the top of the piston to see it’s condition but it sounds like an electrical issue. You stated it was not getting spark so I’d start down that route. ECU, coil, stator all electrical connections......
mattyhamz2 wrote:
Should have updated more. He was able to get spark last night and just for safe measure put in a new plug this morning and still...
Should have updated more. He was able to get spark last night and just for safe measure put in a new plug this morning and still getting strong spark. Plan is to check the injector next but wanted to hear more info about the guys with the cracked pistons.
colvin227 wrote:
Yeah on to the fuel I’d say......you aren’t getting any ECU diagnostic faults? Evident of a light on the holeshot map switch? To rule out the...
Yeah on to the fuel I’d say......you aren’t getting any ECU diagnostic faults? Evident of a light on the holeshot map switch? To rule out the piston thing, like I’ve said running a small diameter scope down the plug hole should tell you all you need. Some auto parts places have them to rent out if need be, or pulling the cylinder isn’t too in-depth for the average wrench. If it passed a compression check, and if it would pass a leak down test then I’d doubt the cracked piston theory. But never know and I guess peice of mind is to just have a look.
Nope, no faults showing up. He is going to check the injector first and if that checks out he will be pulling the head off. We usually do all of our own work so we're not afraid to rip it apart, just didn't want to if it's not needed. Figured we'd try to go everything electrical/fuel related before diving in to the motor.
Rotaholic
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Rotaholic 1/24/2019 12:41pm
1/24/2019 12:41pm
Maybe hook the fuel pump up to 12v and make sure it's working, and I would definitely check the timing if you haven't already, it may have skipped a tooth or slipped on the cam
mattyhamz2
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mattyhamz2 1/24/2019 12:46pm
1/24/2019 12:46pm
Rotaholic wrote:
Maybe hook the fuel pump up to 12v and make sure it's working, and I would definitely check the timing if you haven't already, it may...
Maybe hook the fuel pump up to 12v and make sure it's working, and I would definitely check the timing if you haven't already, it may have skipped a tooth or slipped on the cam
He just called me and sent a picture. Piston cracked almost exactly like DC41's pic just not quite as large.
Rotaholic
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Rotaholic 1/24/2019 12:49pm
1/24/2019 12:49pm
Gutted, sorry to hear that. At least you caught it now, I haven't heard of that issue but sounds like a few have had this
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yz133rider 1/24/2019 1:00pm
1/24/2019 1:00pm
No other damage? Slap an upgraded piston in while in there and gain some power? Hopefully thats the case and its an easy fix and good time to upgrade!!
mattyhamz2
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mattyhamz2 1/24/2019 1:04pm
1/24/2019 1:04pm
yz133rider wrote:
No other damage? Slap an upgraded piston in while in there and gain some power? Hopefully thats the case and its an easy fix and good...
No other damage? Slap an upgraded piston in while in there and gain some power? Hopefully thats the case and its an easy fix and good time to upgrade!!
Nope, no other damage. Haha I asked him about that but he wants to keep a standard piston in it. Usually keep all of our bikes stock other than a pipe and wheels/oversized front rotor. He was actually relieved that's what the issue was and not something worse.
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yz133rider 1/24/2019 1:07pm
1/24/2019 1:07pm
yz133rider wrote:
No other damage? Slap an upgraded piston in while in there and gain some power? Hopefully thats the case and its an easy fix and good...
No other damage? Slap an upgraded piston in while in there and gain some power? Hopefully thats the case and its an easy fix and good time to upgrade!!
mattyhamz2 wrote:
Nope, no other damage. Haha I asked him about that but he wants to keep a standard piston in it. Usually keep all of our bikes...
Nope, no other damage. Haha I asked him about that but he wants to keep a standard piston in it. Usually keep all of our bikes stock other than a pipe and wheels/oversized front rotor. He was actually relieved that's what the issue was and not something worse.
Im all for stock too generally but a quality piston from wossner or cp isnt a bad idea in my uneducated opinion. I certainly wouldn't go with an oem if they are prone to cracking like this.
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mattyhamz2
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mattyhamz2 1/24/2019 1:13pm
1/24/2019 1:13pm
yz133rider wrote:
No other damage? Slap an upgraded piston in while in there and gain some power? Hopefully thats the case and its an easy fix and good...
No other damage? Slap an upgraded piston in while in there and gain some power? Hopefully thats the case and its an easy fix and good time to upgrade!!
mattyhamz2 wrote:
Nope, no other damage. Haha I asked him about that but he wants to keep a standard piston in it. Usually keep all of our bikes...
Nope, no other damage. Haha I asked him about that but he wants to keep a standard piston in it. Usually keep all of our bikes stock other than a pipe and wheels/oversized front rotor. He was actually relieved that's what the issue was and not something worse.
yz133rider wrote:
Im all for stock too generally but a quality piston from wossner or cp isnt a bad idea in my uneducated opinion. I certainly wouldn't go...
Im all for stock too generally but a quality piston from wossner or cp isnt a bad idea in my uneducated opinion. I certainly wouldn't go with an oem if they are prone to cracking like this.
I asked him about a CP or any other but he was pretty firm on stock haha. Believe it or not, I can't think of a time we haven't used an OEM piston in any of our bikes since I was a kid.

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