103B Engine sputtering . . .

[anathema]

. . . or "missing" as I would better describe it. It is in an early 2007 Thunder Mountain Keystone and is still under warranty through my local Harley Dealer that it was bought from. I bought the bike because its "90%" Harley and warrantied by through Harley dealers. It is still 100% stock (from Thunder Mountain), exhaust etc.

At 800 miles, it started "missing" and subtley jerking (and no, not of the engine lugging type) the bike. The other symptom was excessive popping and crackling from the Supertrapp 2 into 1 exhaust when decelling. I took it to the dealer and they found oil in the gasoline so replaced the valve seals. That was fine, and corrected the "missing" problem and the exhaust popping.

BUT here I am 1500 miles later and it is doing it again. I can only assume that it is the Valve seals again but I don't want the dealer to just replace them again if I'm going to have the problem again in another 1500 miles. I only have a couple of months of warranty left.

My problem, knowing little about Harley's V-twins (and though still minimal, AI Magazine has advanced my knowledge significantly since I started subscribing), is:

1. How do I get my point across to the dealer (when they know that I know nothing) that something must be causing the valves to fail prematurely and I need it fixed now while under warranty?

2. What could cause the valve seals to fail so quickly?

3. Is it possible the valve seals were leaking even after first replacement fix and it just took 1500 miles for the spark plug to foul up enough to cause the engine to start "missing" again?

It is at the shop right now and the service rep has already called once saying that the excessive exhaust popping and crackling is just something the TM Keystone does and that they could perfomance tune it on the Dyno (at my expense). I told her that 3 buddies and I walked in and rode out on 4 TM Keystones last fall and I'm the only one with this problem, so save the "thats-just-how-they-run" speech for someone else.

I then reminded her that that wasn't even the real reason that the bike was brought in . . . it was the engine problem of which the exhaust issue might simply be a symptom. I then got the "Oh, let me check with the Tech".

Sigh . . . .

[frisco-rigid]

I am sooo proud of you, yeah, you really did say that huh,,,, oooh yeah...

-----so save the "thats-just-how-they-run" speech for someone else.----

Ha, you're learning quick...

If TM's sickles are prone to excessive exhaust popping and crackling it's prob because TM must lean the air-fuel mixture to get EPA certification, messed up huh...
It would prob be in your favor to get re-mapped if you're EFI,, however, if you're carburated, we can help...

Don't know why the valve seals would be an ongoing prob, but someone here could have an idea... But, forgive me for second guessing you when you say that the popping and cracking ceased when they originally replaced the valve seals... Are you sure the popping and jerking and crackling stopped after they replaced the seals,, that just puzzels me...

I wish I had sugestions for you anathema.
I'm still trying to figure out how they figured out that your valve guide seals were leaking and somehow getting engine oil into your gas tank??!!??
WTF?
If you intake guide seals were leaking you would get oil into your combustion chamber and foul the sparkplug.
If your ehxaust guide seals were leaking you would have slightly smokey exhaust and eventually sticky valves.

[anathema]

See, I told you I was a newbie. When I said oil was mixing with the gas, I meant in the combustion chamber. But you did raise a question:

What is causing the engine to hesitate, a fouled plug (as it gets worse) or increased oil leaking in from the valve seal (and it was the dealer who told me the valve seals were leaking). i.e.- without replacing the seals but with new plugs would it still hesitate?

[frisco-rigid]

I still think it's a mixture prob... BUT, the fouled plugs are puzzling...
It would have to be a very large contamination of oil in the combustion chamber to cause the motor to hesitate and miss... Generally an oil contamination in the combustion chamber would show up as blue smoke at the exhaust along with fouled plugs... Glad to see dls8 on the job..!!

Just because your buddys with identical sickles don't seem to be experiencing the same probs that does not mean much... They all behave differently...
These are devil machines, especially since they are from some "custom" maker...

Are both plugs fouled or just one side? When they replaced the seals or seal did they inspect the whole head? I have seen bent valves and cracks that has caused leaks. They may need to pull re condition the head. Could be a casting problem from the beginning.

Pops like Frisco says is usally a lean mix or leak in the intake. Has that been addressed.

If my plugs kept fouling out I would pull the heads and start looking. On one occasion I had a crack in a cylinder wall and the oil was getting through pass the piston rings. Had to get it resleeved. At that point are your piston rings bad? They put the wrong ones in? Its happened before. I would insist they tear down the whole top end and look it over. It happened to me. I got my way and they found a warped piston. There. Mud in their face cuz they said I was hearing things.

[anathema]

Thanks for the insight. The service rep has yet to get back with me since I dressed her down last week. I'll be sure to use some of this advice if they come back again with the "its what they do" BS.
Thanks