1200s valve failures?

[mfrane]

Is there any history of valve breakage in 1200s motors? Are the valves one piece forgings or two piece welded head to stem, and what is the valve material? My motor broke an exhaust valve.

[shreddr]

did it trash the top end? more details man, was your bike modified, do you rev the piss out of it, what were you doing when it let go, how many miles on your bike, VIN#

[mfrane]

Yes, the left cylinder was trashed ;-( Presumably, one of the exhaust valves heads broke off and munched the piston etc. The second exhaust valve head was imbedded in the piston. The spark plugs (DCPR8EIX) looked as though the were hit with a hammer to smash the electrodes. I was in 3rd gear banking left with a steady throttle in the 5-6k range when I heard a clatter, sounding like it came from the gas tank, pulled in the clutch and coasted to the shoulder. No warning lights no smoke no oil leaks. Called for the trailer. Dealer techie said "you over rev'd it causing valve float and piston contact with exhaust valve" Only mods were cat removal and Iridium plugs. Still in "warranty" discussion.

[mfrane]

Forgot, don't rev the snot out of it, but ride it fast. Dealer looked at the well worn BT016s and said " I was racing the bike" in other words I caused it. My jacket says Ku****ani Racing, so I guess that confirms it. Mileage is 13K.

[turboflyer]

You may want to get your order in to SJBMW for the high pressure valve springs. I do not know what the actual pressure is over stock, but I know they do. Sorry for the loss. Glad you pulled it off with just metal parts needed.

[cageyar]

Originally Posted by mfrane

Yes, the left cylinder was trashed ;-( Presumably, one of the exhaust valves heads broke off and munched the piston etc. The second exhaust valve head was imbedded in the piston. The spark plugs (DCPR8EIX) looked as though the were hit with a hammer to smash the electrodes. I was in 3rd gear banking left with a steady throttle in the 5-6k range when I heard a clatter, sounding like it came from the gas tank, pulled in the clutch and coasted to the shoulder. No warning lights no smoke no oil leaks. Called for the trailer. Dealer techie said "you over rev'd it causing valve float and piston contact with exhaust valve" Only mods were cat removal and Iridium plugs. Still in "warranty" discussion.

This is why dealers earn their bad reputation. Did you ask him how he made the over-rev determination? If his answer is the broken valve, ask him how does he tell the difference between a defective valve and one damaged by over-reving.
The only answer to that question is he can't tell the difference and regardless of his clairvoyance regarding your tires, his opinion is simply his opinon based on no facts. You need to be adamant on your actual usuage, rpm, etc. and contact BMW directly. This dealer is doing nothing for you and you need to go around him. If you bought the bike from his store, that add insult to injury.

[signit98]

Yeah, sounds like just another moronic dealership...

You need to be adamant about it and really, if there no other way, move on to another dealership...

Like cageyar said... there is no way (without extensive lab-testing) to determine how the valve broke... to use tires as an indicator is even more ridiculous (i.e. moronic) I can scrub tires to oblivion without going anywhere near the red line) and just proves that they are either clueless or don't care... most likely both!

Make noise, lots of noise... forums, whatever... contact BMW directly...

[pmc847]

How do you over rev with a rev limiter?

Philip

[flynford]

Originally Posted by pmc847

How do you over rev with a rev limiter?

Philip

Exactly!!!

[roger albert]

How do you over rev with a rev limiter?

There are a ton of ways, but the two common are a sudden break in traction at the rear at WOT (system can only reign things in so fast when not under load) and a downshift at too high of an rpm.

Note, not saying that was even vaguely the case. Just saying thinking a rev-limiter will save you from all over-rev scenarios is a non starter.

No good way to know what happened here. Once bits are bent, it's tough to ascertain what's cause and what effect.

Dealer still sounds full of crap.

[fralind]

Hello together.

My English is not very good, see it after me.

The reason for the outlet valve or white has been the course of time new SW Estates (11.x and above) played on the BMSK.
Therefore, the engines run lean (Lambda 16 and up), what are they sending you leads to hot exhaust gas temperature can not be removed through the valve seats, and it comes to demolition.


This is my 12 S with Woessner Langpleuel and pistons, worked head, larger injectors, and a custom BMSK (SW 9.2) RapidBike3 (Lambda 8,7), Boxer Burner and Zard exhaust system.


Here is a series machine. Kurven bottom of the lambda seen. how strong they emaciated.

[OwenM]

Originally Posted by roger albert

There are a ton of ways, but the two common are a sudden break in traction at the rear at WOT (system can only reign things in so fast when not under load) and a downshift at too high of an rpm.

How does an engine continue to gain rpm under full throttle past the point where the ignition is cut?

[peter f]

Originally Posted by fralind

This is my 12 S with Woessner Langpleuel and pistons, worked head, larger injectors, and a custom BMSK (SW 9.2) RapidBike3 (Lambda 8,7), Boxer Burner and Zard exhaust system.

Hmmm

Now...we are up to something I suspect. Can you share some info more?

Q:

1a. Since nobody can tell (AFAIK) how BMSK-RB3 coexist (and collaborate, so to speak) why you choose build 9.x? Doesn't that idiot RB3 thing "correct" things?

1b. Who programmed your BMS-K? (if custom means that).

2. Larger injectors > where?

3. Do you know anyone doing proper valves, springs and rocker arms? (Timo Roessner, for instance, never answered my questions).

[PFFOG]

Again not insinuating it happened in this case, but over rev is easy with an errant downshift. BUT, it would be impossible to prove that unless the computer saved such info, and as he customer you should get the benefit of the doubt.

Years ago when I was the Service manager at a Saab dealer, we had a guy bring his car in with the engine grenaded, and the forces were so severe that it sheared off the seven grade 8 and hardened alignment pin that hold the flywheel to the crankshaft!

We inquired about the events leading up to the failure and he said his wife was driving along and it just quit and made a big bang. We suspected something different, but the Factory rep said warrantee it, as we had no proof otherwise.

A while later another customer came in and asked what happened to Mr X's car, and let the cat out of the bag that he was at Watkins Glen racetrack when it happened And when it happened, the owner admitted that he stuffed it into 1st and not 3rd on a downshift.

[AntonLargiader]

I've experienced (or seen) over-revved boxer engines and IME they tend to bend valves and pushrods first. Nate's R12S, for instance, bent a pushrod. If the engine is run with a bent valve for long enough, the head will come off but that tends to leave characteristic marks on the piston. So if there are a lot of chew marks on one edge of the valve pocket(s) in addition to the random dings from the valve head bouncing around, I'd lean toward piston-valve contact (possibly from overrevving) as the root cause if I were making the call. I would then look to see if there was damage on the cam sprocket from mis-installation, or check cam timing itself if that hadn't been lost in the disassembly.

Without those marks, I'd fall back on the assumption that the valve failed some other way, possibly from overheating although it's equally likely that it will burn through at some point rather than simply break. I'd probably start that investigation on older bikes by comparing injector flow, but on the R12 it shouldn't be an issue since each cylinder is basically a complete engine.

[shreddr]

Originally Posted by fralind

If I interpret this correctly, you have the Wossner piston and rod kit, Boxer Burner cams, RBIII, a Zard exhaust, ported head, larger injectors, and some type of software rewrite. Sounds awesome, and where I plan on taking my bike to, of course the 143 HP is very impressive. The only question I have is how does your dyno get a 125RWHP reading out of a stock (128hp) bike?

where did you source the software rewrite, and can you provide more details on the larger injectors, and how you determined they were needed. who did the port work? who tuned the RBIII? thanks

[tjs]

I have only had 2 come through the shop. Both were R12GSA's. Both grenaded the right side head. Both were exaust valves. One Customer did his own 12 K but valve setting on the left head was in spec. The other was caused from a tech. who is no longer employed here. He failed to tighten adjuster lock nuts on the exhaust valves. Right side only The customer heard the clatter but ran the bike till it quit. Identical to origanal Post. Valve head pops off and destroys primary spark plug before logging itself in the top of piston. Don't forget that the valve stems are hollow and filled with sodium. If bike is still in wtty. .. Should have a new short block, cylinders and heads. They have to be built for they no longer sell complete engines. Also oil cooler and hoses shoud be replaced. 2 cnts. from tjs

[jduke]

And like others have said, don't mention "lawyer" until you've exhausted all options with BMW NA.

[turboflyer]

Very good insight and diagnostics mentioned above. Some may not realize that even with a rev-limiter any vehicle with a standard transmission can me over rev-ed, red line exceeded. The valve train does not know why it is moving, only that it is. When one down shifts under the right conditions, with out a slipper clutch the red line can be exceeded. Couple this with excessive EGTs from over lean; things get real volatile. I do not know if the BMW motorcycle ECU logs this event, but many car ECUs do. The reason I bring this up is the dealer may be able to verify the RPMs at which the failure occurred. On another point not directly related if you are planning on buying a vehicle with a std. trans have the shop pull the ECU data log to make sure the previous owner has not abused the engine. This type of abuse does not always show up immediately. Good luck on the fix.

[Deans BMW]

Originally Posted by mfrane

Is there any history of valve breakage in 1200s motors? Are the valves one piece forgings or two piece welded head to stem, and what is the valve material? My motor broke an exhaust valve.

To answer your question directly, no there is no history of R1200 engine valve breakage. As pointed out in the above posts, it is for all practical purposes operator error.