Twin Spark Plug Problem

bikpaintr · 09-10-2004, 06:02 AM

Found this on the MOA forum and thought it might be of interest to some of you with 04 & later bikes.
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"Two days ago I'm riding my RT when it suddenly starts making this godawful knocking sound from the right side of the engine. Fortunately I was only a couple of blocks from the house, so I rode it home and had it towed to the dealer. They opened it up today, and found that the lower plug had broken off inside the cylinder and damaged the piston and valves. They said that they had seen a rash of these problems recently with the porcelain breaking off of Bosch plugs. To make matters worse, they said that they could only put Bosch back in once the repairs are done - at least 10 to 14 days. "

tominator · 09-10-2004, 06:07 AM

I think someone was sleeping with someone’s wife and the bike was compromised. Never heard of a plug letting go like that. Do remember the bolt in the cylinder trick for getting back at people!

Really has nothing to do with being twin plugged IMHO

Tomas

Moybin · 09-10-2004, 07:15 AM

All the years I was in auto parts I never heard of a plug failing like that. There must be a couple of billion plugs in the world, running, at any one time. How weird is this?

roger albert · 09-10-2004, 07:15 AM

Well, if there really is a rash of them, and we're not seeing it on single sparks, then it IS a twin plug thing. Poorly selected plugs disintegrating in the chamber is by no means unheard of. It is the first I've heard of it on these though. The question then is why? Mechanical tolerances? Thermal? Detonation? Just a run of bad plugs? Is the bottom plug the same as the top on this design?

Roger

Firebolter · 09-10-2004, 07:47 AM

If I remember what repoe told me, the plugs are different between top and bottom.

JonyRR · 09-10-2004, 07:52 AM

nd plugs used to have the same rep for self-destruction; i never believed it, but I got a bunch of plugs from the rep in the early 80's and the first time we tried 'em in a fancy-racer sikkle, a plug lost it's porcelain and grenaded a spendy motor...waah...those 'free' plugs turned out to be very expensive.
OT: if you ever wanna get real even, 8 OZ of uncatalyzed polyester laminating resin in the engine oil and in 100 miles, solid bottom end when the motor's shut off...that's realllllly mean. (oops, why did I just say that?)

tominator · 09-10-2004, 07:55 AM

JonyRR?

Nice!

Firebolter · 09-10-2004, 09:10 AM

JonyRR, I hope I never piss you off, between your electronic shennaigans you could pull and the other creative things you could do......Lets just say I won't cross ya!

ErricZ · 09-10-2004, 09:45 AM

mmmm, is that thermite I smell?

Moybin · 09-10-2004, 10:15 AM

If you can smell thermite, you are TOO CLOSE!

Any kid that grew up in the '50s and '60s potentially has a lot of underground knowledge. School was different back then, particularly when you had the drive to get good grades rather than end up in a rice paddy with Charlie shooting at you. Kids today... I wonder if they could break out of a wet paper bag.

My daughter is taking night coursed to finish her degree at the community college. Enrolled in basic chemistry class, they don't even do labs! She's always rushing to me to ask metric conversions that I don't even have to think about to make. Scares heck out of me to think that she's one of the brighter ones! WTF... A nation of information poor, MTV rich lemmings!

I'm NEVER going to get to retire...

JonyRR · 09-10-2004, 10:25 AM

like I said moybin, our sociey's dead, it just hasen't hit the ground yet. When I can out-analyze and out-think most CS majors who eat and brathe this stuff, we as a society are in trouble. 5% of the kids are well-educated and think, the other 95% have never ben taught HOW to think, just WHAT to think, and they usually can't comprehend the difference...truly sad. We are living the decline and fall of the Roman Empire daily...
OT again...go do a google on 'George Heyduke's complete book of dirty tricks'.....mercy!!! 'no such agency' should'a never cut him loose...

Anton · 09-10-2004, 10:26 AM

Thermite, hehehe, cool.

Thermite in a coffee can is the best way to make ice fishing holes, no need for that stinkin' auger. Chemistry and household products (well shop products in this case) are too much fun.

And Moybin, not to depress you, but no, you will not get to retire, sorry.

Moybin · 09-10-2004, 10:35 AM

Yeah, my dad's generation will have sucked the retirement coffers dry long before I'm old enough to check out. He tries to justify it by saying there will be plenty of $$ for me and my siblings when he passes on, but I'll be 80 before that happens, and what the heck can I do that's cool when I'm 80? I mean I hope I'm still riding (and chasing tail), but the Bell Curve says I'm being overly optomistic. Personally I'd rather go down shooting up bad guys in the streets. Too much Viet Nam Era in me, I guess.

Nuke 'em all, let God sort them out.

yetidave · 09-10-2004, 03:35 PM

"To make matters worse, they said that they could only put Bosch back in once the repairs are done - at least 10 to 14 days. "

Why the hell would they be required to use Bosch plugs?

Moybin · 09-10-2004, 04:51 PM

Might be that only Bosch makes a plug with the right length & electrode combination to fit. I'd be surprised if there wasn't another part number in a different brand that would fit, but they don't have a cross-reference for it yet (of don't want to publish it).

bikpaintr · 09-10-2004, 05:23 PM

Most shops around here seem to only sell the factory specified plug. Also since it's a warranty repair they may have to use what BMW specifies.

jackbunce · 09-11-2004, 04:00 PM

Quote:

Originally posted by Firebolter
If I remember what repoe told me, the plugs are different between top and bottom.

Top plugs are: NGK BKR7EKC BMW P/n 12 12 7 653 771

Bottom plugs are: Bosch YR6LDE BMW P/n 12 12 7 681 415

JonyRR · 09-11-2004, 09:43 PM

So herre's another hypothetical; when a twin-plug conversion gets done next, would it be possible to machine both plug holes so the main plug is an equivelant to an NGK B8ES and the small plug hole is the equiv of a NGK D8EA (nice common plugs that are wonderfully reliable and easily obtainable) this non-resistor plug type has the added benefit of functioning optimally with nology coils and wires. Hmmm...something I'm going to look at when I either tear mine apart or hopefully find a doner 1200C motor...

Moybin · 09-12-2004, 06:45 AM

JonyRR:
Only physical condition that would prevent modifying the head as you propose woud be the length of the plug vs. the thickness of the metal in the head. If they are close (meaning the plug equal to or shorter than the metal thickness) then the machinist doing the mod should be able to mill & tap so that the plug electrode is exactly in the 'squish' zone of the head space. No contact with either the piston or any valves.

That's the only thing I can see preventing your mod.

motoyoyo · 09-12-2004, 08:02 AM

You could check with San Jose BMW to see what spark plug they use in their 2 spark conversion. TwinSpark SJBMW
$485 for the complete conversion, including the extra spark plugs

Not a bad deal.
They claim 2hp increase. Anybody here done this?