Thanks guys. I'm still waiting to hear back from EJK. Kinda bummed they haven't emailed back.

I tried playing around with the settings more to be certain that's not the problem. (Or is) Surprisingly that noise at 5k is gone! Bike ran like crap though. In lower rpm's it stutters and hesitates like before, then suddenly will surge forward with a blast of power. Higher RPM's it runs decent.

Didn't fully test it out though. I don't feel comfortable driving when there's a problem like this. Few more days and I'll open her up for a look see.

 

I cleaned up the plug and took her out for a quick ride. Came back and immediately pulled the plug. It was darker. But this time I noticed what looked like something wet on the plug. I shined a flashlight down the spark plug hole and it looked like oil might have been on the piston. I carefully put a chopstick down into the hole and tried to get a little off. It was something wet for sure. If I had to guess, yeah oil. Any chance that could have been unburnt fuel? Didn't smell like fuel at any rate.

My oil window isn't milky and coolant is the right color and has remained at a constant level since refilling it. That should rule out a blown gasket. Would you think the rings?

Anything else would cause that?

Gonna check the timing now. As TheDoc46 mentioned, I can pop the cover for a look without taking it apart took much.

 

Timing chain looks spot on. Compared it to pics I took before removal and the service manual. Kind of hoped that was the problem. We can eliminate that.

 

You can easily tell the difference between fuel and oil. For starters I'm sure you know what it smells like, also if it was fuel it will evaporate quickly. Oil is a different smell, is a lot thicker consistency and will not evaporate within a couple of minutes.
If it is fuel it is just a tuning issue, if it's oil you have other problems. Oil would indicate valve guides, valves or rings. If the rings were done properly I guess it indicates valve guides or valves as the problem.

 

Yeah, it must be oil. Didn't have a gas smell at all.

I'll give Bill a call and ask him about the rings issue I mentioned in the OP. He must not check his email too often.

There isn't much chance of screwing up the valves or guides in a big bore install, right?

 

This will prob sound like a terribly silly question, but here goes.

After opening up the head cover today, I learned that the engine can be TDC but the markings on the cams (the "IN" and "EX") could be in different locations - on the outside or inside, just depending how your cranked it. I guess it doesn't matter which way so long as they're put back the same.

I snapped this pic after we removed the cover before the install:



You'll notice the "IN" and "EX" are on the inside.

Now I'm almost 99.9999% positive we put them back the same way. But let's say we screwed up and put them back with the "IN" and "EX" on the outside, like this pic:



IF we did that, would that explain what I'm experiencing now? Or would the engine be dead by now?

(I did mention stupid question, right?)

 

It is a 4 cycle engine, 2 strokes/cycle. If the cams are installed at the wrong TDC, the ignition would be firing on the end of the exhaust stroke and both valves would be open. So I don't think the engine would run if the cams were installed at the wrong TDC.

Now for the bad news. If it was oil, i would suspect that your piston rings are installed wrong. The compression ring should be the top one and the oil ring the lower one. And they have a top & bottom (at least the compression ring does). Did you take a detailed picture of the rings before install? I mean really close, if not it would be hard to decide. You mentioned that the rings looked wierd, I wouldn't believe that someone took them off and then reinstalled them, but the original install guy could have messed up.

You could put a super hot plug in it and test if it fouls too, but there could be consequences to that. But at this point your looking at going back in, if you determine that it is not fuel/ignition related.
I guess your messing with the FI system, I'm not exactly sure how it operates so I can't really comment on whether it could put out so much fuel.

 

I had hoped that I was wrong about your problem being oil intrusion but the way you described your "mechanic" and the issue of having to "fiddle" with the rings' placement on the piston seemed to add up.. There is no room for error regarding rings - lets hope he simply lined up the gaps , or lined them up close enough together, to allow oil a straight shot to the combustion chamber. If so, it's a relatively easy fix.. But if the rings are upside down and/or in the wrong land... Well that's a little more involved to fix correctly since they have likely "seated" at this point..

Either way, you've probably gotten lucky as you still have a running engine that, no doubt, can be fixed relatively cheaply - it could be far worse..

 

The rings showed up already installed. I was hoping it was Bill who installed them. Saw a YouTube vid from a guy who had his big bore and he mentioned the piston showed up with the rings installed.

To rehash, I bought this big bore from someone who didn't use it. It crossed my mind he may have installed the rings. But a member of advrider said his came installed as well. So maybe they're all pre-installed.

Not sure if the color of the rings really mean anything, but the dark ring was on top. Buddy mentioned usually that one is under the lighter color one.

On a side note, would rings installed incorrectly cause a ticking sound?

 

Thanks for that reassurance. I'm new to the inner workings of engines if you didn't notice.

I didn't take any pictures of the rings unfortunately. I'll post some up when I go back into the engine. I'm halfway there already. Might have time to do it tomorrow.