Spark Plugs Slightly Wet- Diagnosis?

mattymatt716

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Thanks in advance for your help- I'm grateful to be a part of the community!

I have a 2004 with about 47k miles on it. Idle has been mildly inconsistent, power surges at low rpm's (especially when trying to *maintain* speed at lower rpm's), and when cold it will start but then slowly creep down in rpm's and die. When I restart again, it stays running.

I put a TRE on a couple of years ago thinking that this would fix the "surging" issue- and it did, for the most part. Not sure it was the best idea, but I didn't know that at the time, and I really like having a gear indicator.

Was planning this past weekend to do some basic maintenance (oil change, inspect brakes, air filter, spark plugs, etc.) and when I pulled the plugs, I was not very happy to see what I saw.

All four plugs look similar. They were easily wiped off with my thumb, so they weren't "dripping" with oil, but I recognize that this isn't normal.

I do not ride hard, and it is rare that my bike sees high rpm's. I mostly ride on the interstate.

My plan of action:

1) Remove injectors and inspect. Intend to send them out to be cleaned and flow checked because I think they will look like the plugs.
2) Remove fuel filter and inspect. Clean out fuel filter. Replace o-rings so no leaks later.
3) Check valve clearances. I have had the bike for about 12k, but I seriously doubt that this was ever done.
4) Adjust valves if necessary (leaning into this community for help since I have never done this).
5) Remove TRE. Keep gear indicator.
6) Put everything back together, pray, and try it all out.

Thoughts? Any advice would be appreciated.


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Shouldn't your bike smoke pretty badly if that is actual oil in the tip of the plug? I don't know much about internals of a motor, but im thinking a compression check should tell you if there is bigger issues or take a look inside with one of those small cameras that you stick in the spark plug hole while looking at a screen.

Hang in there, the more experience guys would be along to give you some ideas.
 
Gasket, rings or valve guides/seals. With the idle and rpm issues, I'd lean towards valve issues.
 
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Compression (cold):
1- 110 psi
2-120 psi
3-120 psi
4-120 psi

I recognize that the test should be done when engine is at operating temp, but I have everything off the top including the tank (so much easier to work on without the tank, by the way). After I go through the fuel pump and clean it out and then replace o-rings, I am planning to valve check and adjust as necessary. Then new plugs.

Good idea with the camera. I know they aren't expensive- I was planning to order this weekend. I did get a chance to look at the valves.... There is buildup on all of them, but from what I hear and what I've seen, that isn't particularly abnormal. In either case, I don't like it. From the research I've done, running rich and bad gas can cause the buildup.

I'm thinking that this may be a product of a bad tune and running anyway for years. After I take care of all I know to do, I may try to get it tunes (Schnitz Racing) and go from there.

Compression seems pretty consistent- again, this was done COLD, so operating temp psi will be higher I think (considerably, actually).
 
Regarding rpm's and valve issues- surging only happens at low rpm's, not consistently. And, as soon as I twist the throttle, there is no hesitation at all. Wouldn't valve issues be heard or felt throughout the entire range? I haven't been much of an engine guy, but I'm eager to learn and I'm not afraid to turn a wrench and read a book. I'm open to suggestions.
 
Valves will from this time and going forward be called babes! I like it, our busas have babes!
 
I don't know if the valves have ever been adjusted. If the rest of the maintenance can speak to that (before I purchased), I would bet that they have never been checked at all. That is on my list to do.
 
Be careful... adjusting those babes, they tend to lash out. :hijack:hijacked!



If it were mine. I would remove the head, inspect the valves (babes), guides etc. Also look for cylinder wear while your there.
 
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Your measured compression is about 75-100 psi light. Check the valve adjustment. Do a leakdown test to see where it is losing compression.
 
Since I did the compression test while the engine was cold, I would expect the psi to be considerably below specs for an engine at operating temp. Would this not explain this? Minimum spec psi is 170psi, but that's with a warm engine.
 
Got the fuel pump out tonight. Filter looks dirty, but didn't appear dirty enough to restrict flow. I thought I grabbed carb cleaner last time I was at AutoZone but I grabbed brake cleaner instead. So, tomorrow I'll be cleaning it out and then re-assembling.

FWIW- Tank looks pristine- no rust, no buildup, and the fuel pump looks immaculate. I wouldn't believe that this bike has almost 50k on it.

Once the fuel pump is back in and the tank is back on, I'll plan to start the bike and do a warm compression test to see where I am. After that, the injectors will be coming out and sent to MPS Racing for cleaning and flow check.

I plan to check the valves as well. I'll need to do some reading up as I've never done this before. If they need to be adjusted, I'll call in some backup so that I don't screw the timing up.

I appreciate the ask, 13013!
 
Over $50 just for the fuel strainer?!?! Absolutely outrageous! The part # is below. I'll be looking at eBay options.

15420-24FB0
 
Agreed the engine should be warm but going on my experiences you aren't going to make up that much compression, 50 psi to get to min. is a bunch.
 
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