Revised Valve Specs

[itsatdm]

I called my dealer today and confirmed the valve lash they are using is what is now the new spec. No indication on their computer how or when this happened. But they will do some research and get back.

My Haynes manual has the old spec.

Lose HP? Theoretically yes, but I doubt you will feel it.

I have a KLX680c that I am constantly experimenting with to get the last bit of HP. I set the intakes at minimum spec and the exhaust at maximum. It did make the bike rev easier and quicker at higher rpm. Less power lower in the rpm range.

The intakes opens farther and it extends the duration the valve is held open. The exhaust valve stays closed longer on the end of the power stroke. By the time it opens there is less cylinder pressure. I check the valves often to make sure the intakes don't get tight. Something I felt comfortable with on this bike because there are 2 versions of it and that is basically what Kawasaki does with different intake cams on them.

I won't do that for the BMW because it is a PIA. Next time the valves are done, I probably set them where old and new overlap.

[Emmbeedee]

Originally Posted by Gangplank

Just talked to a shop I trust up in Chico CA. Said the valve specs were changed but recommendation from the shop is to just wait until the next interval and then check and change it if needed. I let him know mine were just done and he said it can still wait until the next needed valve check... Sounds ok to me.

Makes sense. My bike needed its checkup so it was logical to do it now, and my wife's 650 had just had its 80K checkup a couple of months ago, but we got a break on the valve check price so it made sense to do hers now too.

But if either of our bikes had still been in use (ie no snow on the ground) we probably would have waited.

[Gangplank]

Originally Posted by Gangplank

Just talked to a shop I trust up in Chico CA. Said the valve specs were changed but recommendation from the shop is to just wait until the next interval and then check and change it if needed. I let him know mine were just done and he said it can still wait until the next needed valve check... Sounds ok to me.

Even better... Just called Sierra BMW here in Reno, the other BMW shop I trust. That is the shop that checked mine in Aug. The service department called me back already and they kept my valve specs from when they checked them in Aug. sounds like I should be good for now. only 2 of the intake valves were .02 tight (measured .20). The rest of the intake and exhaust clearances were within the new specs. Great service!

[NCD]

Originally Posted by Emmbeedee

Makes sense. My bike needed its checkup so it was logical to do it now, and my wife's 650 had just had its 80K checkup a couple of months ago, but we got a break on the valve check price so it made sense to do hers now too.

But if either of our bikes had still been in use (ie no snow on the ground) we probably would have waited.

Having just checked mine, it will be 2 years before I'm back in there. I'm going to leave them be. The collective of 800 motors have bajillions of miles on them at the old specs, and we've all been riding around blissfully unaware of the change. Hell, the specs could change again before I open it up again!

I will admit that its a little creepy riding it knowing they hhave changed. If they would just tell us why.....

[Reaver]

Originally Posted by NCD

I will admit that its a little creepy riding it knowing they have changed. If they would just tell us why.....

It's on a "need to know" basis and you're just a customer!

[ebrabaek]

Originally Posted by CaliKarl

So the new bikes, with bigger clearances, have less power?

No. For you to notice a performance difference... The motor would sound like it's about to grenade.

[Steveman]

Originally Posted by ebrabaek

No. For you to notice a performance difference... The motor would sound like it's about to grenade.

+1 !

[CaliKarl]

Originally Posted by ebrabaek

No. For you to notice a performance difference... The motor would sound like it's about to grenade.

Okay. So why then not keep the clearances loose in the first place? So that they're ringing the dinner bell?

[ebrabaek]

Originally Posted by CaliKarl

Okay. So why then not keep the clearances loose in the first place? So that they're ringing the dinner bell?

It does not make any sense. The other bikes I have all have their valves in the .08-0.22 on the intake side, and 0.18-0.32 on the exhaust side. The next biggest bike is my 55 RWHP Suzuki DRZ 470. A full flood race build motor with just about twice the output as compared to stock. it runs 0.10-0.20 intake, and 0.20-0.30 exhaust. The 8GS changed in two ways. space is moved up, and margin was increased from 0.08 to 0.11 ( exhaust). That margin is pretty standard, as the other bikes I have are 0.10. But as to determine why BMW did this.... My guess is some idiot thought this would be a good thing. That's it. They have prided them self that these valves do not move, thus it is unnecessary to increase the spec's. Mind you as abrasive air is ingested through normal operation ( slightly increased with guaze filters like K&N) over time the valve seat will wear, and the valves will now sit a little higher in their seat, thus decreasing the clearance between shim, and the valve rod. But to increase the tolerances like this is sort of like giving your Yugo a rear defroster to keep your hands warm, when you push it..... except our BMW does not break down like the Yugo.....wait... What did I just say.... IMHO... The old valve specs are plenty. You most likely will not hear any difference in the sound if you change to the new spec's. You would just be wasting your time. This is my opinion only. If this bike had a tendency to move valves... I'd say great, change the spec's to facilitate this, but it does not. Don't sweat it, and just check'em at next scheduled time.

[Reaver]

So I'm at the Dealer yesterday paying too much for parts when I asked the mech for proof of change, Memo, Service instruction whatever. They have the time now and he did look but found nothing. Having bought 3 bikes there recently I trust they would provide me with it if they could.

Ignorance is bliss. I did not read this thread. I did not read this thread. I did not read this thread.

[Gangplank]

It's in the updated manual from what I understand.

[Ratchdaddy]

Originally Posted by Emmbeedee

I did a quick search but didn't see anything in the topics about this.

I got a call from my mechanic yesterday where he said that in September BMW issued revised valve settings for the F650/800 engines. According to him, all the engines he's seen so far will need adjustment as they will be too tight, under the new specs.

He said each shim is about $12, and it'll take a little more than an hour to do, while he's doing my 80,000 km checkup.

I checked my valves today and under the old specs both of my exhaust valves for #1 were tight. I called the dealer to check the availability of shims and somewhere in the back of my clouded memory I remembered seeing something about new clearances so I asked the service manager at Riverside BMW what the specs where.

He gave me the In ,23-33mm and ex .3-.41mm

What that translates into for me is that now all of my valves are too tight for the "new" specs.

My local indie shop said not to mess with it, but the bike has 33K on it and I already have almost everything torn apart. I may as well do it right.

I made a pen change to my Haynes manual, Now if I could just figure out how to make a change to my BMW service DVD.

Between that change in valve clearance specs and the change to the heavier oil I wonder what is going on.

[JRWooden]

I think I would have him do it ....
Since there is so little overlap on the old/new ranges it looks like lots of folks will be buying shims next time around....
With luck he can shuffle some of the shims around and only have to buy a couple....

Maybe we can get a circulating "kit" of extra shims around twin owners ... ???
We have one that circulates around a group I am a member of for Toyota Supra that has OHC engine and uses shims...

[MTrider16]

Intake new .23-.33mm old was 18-26
exhaust new .30-.41mm old was .27-.35

New .009"-.013" Old .007"-.010"
New .012"-.016" Old .011"-.014"

I had to convert he dimensions to get a "feel" for this change.

Ditto on folks comments that BMW thinks there is more seat to face wear than valve train wear in the time interval between valve adjustments. Its a balancing act. If the valve adjustment gets too loose, the open and close ramps on the cam are not used and the valve slams shut on the seat. Too tight and the valves get to hot from not closing properly on the seat.

It seems to me that you can use the old spec and just check them more often, or use the new spec and standard interval. Also if you can record your measurements, you can customize your own adjust interval.

I'm not sure why you think BMW would publish the specs. Manufacturers think end user are incapable of performing maintenance and only Factory certified technicians should work on the engines. European companies are worse in this regards than US companies, but even US companies are seeing the profit that can be gained by keeping maintenance under their own licenced franchise roofs.

David

[Ratchdaddy]

I finished my Valve adjustment this morning. I set them all in the middle of the new specs. I noticed maybe a little more valve noise. I have not switched the oil to 15-50 yet though. Bike seems to run great. I have to put about 350 miles on it this weekend so I should know more by Sunday.

BTW, if you button it back up and you have forgotten to attach those three litte hoses back to the splitter on the bottom of the air box, your bike will run like crap. Ask me how I know that one.