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White plugs and overheating on Evo — Melted Cam Position Sensor (Need advice)
Hi everyone,I'm facing an issue with my Evo motor and could use some experienced advice.The symptoms:A week ago, my spark plugs were a perfect tan/brown color. Suddenly, over the last few days, the engine started overheating like crazy, and the spark plugs turned completely white (bone white).What I have already checked and ruled out:Intake leaks: I checked the carb manifold and cylinder seals by spraying carb cleaner. No RPM drops or jumps, everything is sealed tight.Carburetor: The carb is completely clean, jets are clear.The discovery:I pulled the nose cone cover and found that my original Cam Position Sensor (OEM 32400-94) is completely melted. The potting material/compund is boiled out, and the internal wires (green and pink/red) are exposed and look damaged. It’s safe to say the sensor is dead, and I've already removed it.My questions for the forum:Could a dying/melted ignition sensor cause retarded timing severe enough to overheat the engine and bleach the plugs like this (thermal cleaning from extreme heat), even if the carb is fine?If I install a new sensor (looking at the standard OEM style replacements with pins), should I look into anything else that might have caused the sensor to melt in the first place? My VOES was ungrounded by the previous owner, could that be related?I am attaching a photo of my old sensor to show the damage.Thanks in advance for any insights!
I have a 1986 here that did that.. changing complete ignition did Not Help.. advancing the timing helped somewhat..
I ended up deciding it is an oiling problem...but...The Lifters Never Clatter a drop!! I too am at a Loss currently...tho it is not Dangerously Hot ..it is too hot for my likes.. More so than any other bike on the Farm!!!
I will probably run this one to Failure...then try to identify just exactly was wrong... Not something I suggest to others, however!
I too am currently Clueless...so...Watching any responses!!
While we Wait...check your oil return.. Into a catch can to recycle!! Should be fairly steady at anything off-idle!
Idling, they all "spurt" a bit.. Mine all do anyway!
Describe what you mean by "engine started overheating like crazy". What were the exact symptoms?
As far as you know, is the engine stock? Did you have to drill out the rivets to get to the CPS?
If this was my bike, I'd replace the failed CPS and then run it. Either the problem is solved, or it isn't. If it isn't, you can continue your diagnosis from there. Depending on where you want to go with this, you might consider updating the ignition (eg, Dynatec 2000i) at this time.
Describe what you mean by "engine started overheating like crazy". What were the exact symptoms?
As far as you know, is the engine stock? Did you have to drill out the rivets to get to the CPS?
If this was my bike, I'd replace the failed CPS and then run it. Either the problem is solved, or it isn't. If it isn't, you can continue your diagnosis from there. Depending on where you want to go with this, you might consider updating the ignition (eg, Dynatec 2000i) at this time.
Thank you for reply
Engine is stock , ordered now new cps
Engine overheating i think
The reason I'm sure it's overheating like crazy is that after just a short ride, the engine radiates an extreme amount of heat that burns my legs. On top of that, both spark plugs are completely stark white with zero deposits, which tells me the combustion chamber temperature is way out of spec. The exhaust also sounds very harsh and "dry"
I’ve already verified that the carb is perfectly clean and there are no intake manifold vacuum leaks. So I’m pretty sure this melted sensor was sending a corrupted, retarded timing signal, which caused this massive overheating and white plugs.
Thank you for reply
Engine is stock , ordered now new cps
Engine overheating i think
The reason I'm sure it's overheating like crazy is that after just a short ride, the engine radiates an extreme amount of heat that burns my legs. On top of that, both spark plugs are completely stark white with zero deposits, which tells me the combustion chamber temperature is way out of spec. The exhaust also sounds very harsh and "dry"
I’ve already verified that the carb is perfectly clean and there are no intake manifold vacuum leaks. So I’m pretty sure this melted sensor was sending a corrupted, retarded timing signal, which caused this massive overheating and white plugs.
Also, just two days before this post, the spark plugs were absolutely fine, perfect coffee color. But then, over the span of two days, I noticed the exhaust sound changed and became weird. The RPMs started fluctuating constantly — like "normal, normal, drop, normal". That’s when I rode to the garage, pulled the cover, and found this problem
Looks like too much timing to me, Strap is heated all the way down to the threads. I fix that. Could be the VOES switch or the ignition sensor. It also looks like it's running too rich to me the end of the threaded part is all black. I'd check that after you get the other stuff fixed.
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White plugs and overheating on Evo — Melted Cam Position Sensor (Need advice)
