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I am starting this post because I am concerned about the frequent failure of the ignition coil packs on our XX's. This will be long, so unless you are technically minded, or just a nerd with a curious side, you may want to skip. I am an engineer, a motorcycle shop owner, and an XX enthusiast. This will be an open discussion where I feed information in and hope to get information from all of you and try to come to a permanent resolution to our coil failures.
What concerns me most is that this engine architecture is used in a wide variety of machines from snowmobiles, to watercraft, side by sides, motorcycles and our XX's. Doing some searching over the last few days on other forums, I can not find any wide spread failures of these coils on any other machines but XX's. This greatly concerns me.
What is different about the XX than any other machine that uses this basic engine design that causes the failures? That is the million dollar question. The secondary question is; is there a fix to the problem? Shelling out a couple hundred bucks every few years on coils (for those of us who drive a lot) does not seem like the way it should be. A random failure now and again, sure, I can buy that. But we have constant enough failures people suggest carrying spare coils. This is just silly to me.
As far as engine goes, the only difference between us and the YXZ, our closest cousin, is a camshaft change for more power. As many engines as I have built I can pretty much guarantee that this will not cause increases in coil failures. The next big change is how it is wired into the chassis (wiring looms, grounds, etc.). Since I do not have a YXZ to examine, I am going to shelve this option for now. The final difference is the programming inside the ECU. The ECU seems to be a Yamaha unit, but with what I would guess as Textron specific tuning tables in it.
Many of us with failures have tunes in our ECU's. Alba, Speedwerx, Speed (Alba), etc. But many failures seem to be happening on stock XX's as well. Not everyone has a tune. (I have Alba, Speedwerx full exhaust and intake systems as well). When I get some time, I am going to reach out to Alba and see if I can get in touch with one of their tuners to ask some questions and get some answers to what I am thinking.
The ECU detects misfires electrically through the coil wiring to each coil. While I do not have a full understanding of how it works, it basically watches the voltages and resistances on those wires and can tell because of a phenomena within the combustion chamber that does something electrically when the cylinder fires properly and can compare that to what happens when there is a misfire.
My hypothesis is that this feedback circuit and programming is too sensitive on the XX's. While there may be a fluctuation in the feedback from the cylinder, the coil may not actually be failing. It is like it is far too sensitive over what is found on other Yamaha machines. If I can figure out what specific coil is failing on my XX, I would like to install it into my fathers XX and go for a ride and see if the problem tracks.
If the coils are failing, what is it on the XX causing this? Is there an alternative coil that will be more robust? Why do they not fail in the YXZ? I ended up ordering a set of coils that fits Yamaha sport bikes like the R1, R6, etc. It is similar to the coil that is used on some of the snowmobiles that use the same basic engine design. It does not have the bolt down tabs, but it should work. I can come up with another mounting solution if I am going to continue to run them. The reason I have chosen these coils is that I have worked on countless Yamaha motorcycles in my shop and have never seen one of them fail.
Feel free to chime in. I had repeated failures yesterday and had to restart my car about 15 times in a 30 mile ride. Spark plugs are new and I fully inspected them again (NGK Iridium). I had failures on the last ride with standard NGK's. Motor has only about 800 miles on it after a rebuild and runs perfectly. I just got done checking grounds, battery connections and battery condition (tested perfect, larger than stock racing battery). My battery voltage on the gauge cluster was constant at 14.1 volts at the time of the engine going into limp mode, so I do not think my issue is a battery wiring issue. Could be other wiring though.
My problems started earlier this year on a ride it did it once after going through a big puddle. I restarted and it was fine. Ran great the next couple of rides. Then it cropped up on another ride once. This last ride probably 15 times.
I will keep updating this thread as I have more information. Lets find a real cause and solution to this.
What concerns me most is that this engine architecture is used in a wide variety of machines from snowmobiles, to watercraft, side by sides, motorcycles and our XX's. Doing some searching over the last few days on other forums, I can not find any wide spread failures of these coils on any other machines but XX's. This greatly concerns me.
What is different about the XX than any other machine that uses this basic engine design that causes the failures? That is the million dollar question. The secondary question is; is there a fix to the problem? Shelling out a couple hundred bucks every few years on coils (for those of us who drive a lot) does not seem like the way it should be. A random failure now and again, sure, I can buy that. But we have constant enough failures people suggest carrying spare coils. This is just silly to me.
As far as engine goes, the only difference between us and the YXZ, our closest cousin, is a camshaft change for more power. As many engines as I have built I can pretty much guarantee that this will not cause increases in coil failures. The next big change is how it is wired into the chassis (wiring looms, grounds, etc.). Since I do not have a YXZ to examine, I am going to shelve this option for now. The final difference is the programming inside the ECU. The ECU seems to be a Yamaha unit, but with what I would guess as Textron specific tuning tables in it.
Many of us with failures have tunes in our ECU's. Alba, Speedwerx, Speed (Alba), etc. But many failures seem to be happening on stock XX's as well. Not everyone has a tune. (I have Alba, Speedwerx full exhaust and intake systems as well). When I get some time, I am going to reach out to Alba and see if I can get in touch with one of their tuners to ask some questions and get some answers to what I am thinking.
The ECU detects misfires electrically through the coil wiring to each coil. While I do not have a full understanding of how it works, it basically watches the voltages and resistances on those wires and can tell because of a phenomena within the combustion chamber that does something electrically when the cylinder fires properly and can compare that to what happens when there is a misfire.
My hypothesis is that this feedback circuit and programming is too sensitive on the XX's. While there may be a fluctuation in the feedback from the cylinder, the coil may not actually be failing. It is like it is far too sensitive over what is found on other Yamaha machines. If I can figure out what specific coil is failing on my XX, I would like to install it into my fathers XX and go for a ride and see if the problem tracks.
If the coils are failing, what is it on the XX causing this? Is there an alternative coil that will be more robust? Why do they not fail in the YXZ? I ended up ordering a set of coils that fits Yamaha sport bikes like the R1, R6, etc. It is similar to the coil that is used on some of the snowmobiles that use the same basic engine design. It does not have the bolt down tabs, but it should work. I can come up with another mounting solution if I am going to continue to run them. The reason I have chosen these coils is that I have worked on countless Yamaha motorcycles in my shop and have never seen one of them fail.
Feel free to chime in. I had repeated failures yesterday and had to restart my car about 15 times in a 30 mile ride. Spark plugs are new and I fully inspected them again (NGK Iridium). I had failures on the last ride with standard NGK's. Motor has only about 800 miles on it after a rebuild and runs perfectly. I just got done checking grounds, battery connections and battery condition (tested perfect, larger than stock racing battery). My battery voltage on the gauge cluster was constant at 14.1 volts at the time of the engine going into limp mode, so I do not think my issue is a battery wiring issue. Could be other wiring though.
My problems started earlier this year on a ride it did it once after going through a big puddle. I restarted and it was fine. Ran great the next couple of rides. Then it cropped up on another ride once. This last ride probably 15 times.
I will keep updating this thread as I have more information. Lets find a real cause and solution to this.
