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#749282 - 12/24/11 09:32 PM Re: Valve Adjustment [Re: Whip]
macx Offline
Member

Registered: 03/29/11
Posts: 437
Loc: Cape Girardeau, MO home workin...
I'd like to know, too.

Is the "acceptable range" a similar situation to the others where the dealership won't adjust if it's in that range, but getting the clearances closer to the same will make it run a little better? It's apparently pretty easy to at least do the feeler gauge check. I would like to know how close mine are, not that they're just within "acceptable range."

I used to run solid cams in big blocks and, esp on the 426 hemi, a difference of just a couple thou would make a discernible seat of the pants difference in engine response and power.
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56k since 5/1/11 on my 1200RT - LOTS of scenery within 500 miles of Vegas all directions! Retiring in WY next year.
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#749834 - 12/28/11 01:35 PM Re: Valve Adjustment [Re: dirtrider]
jviss Offline
Member

Registered: 05/19/04
Posts: 777
Loc: Westborough, MA
Originally Posted By: dirtrider
John the shim tolerance range will become apparent given enough time on the product.

So far personally I haven't done enough camheads with enough miles on them to determine a valve setting direction.

As a rule on new engines (not specifically BMW boxers) the valve train seat-in wear exceeds the valve to seat recession so valve gap usually opens up slightly.
Then after a number of miles when the valve train components are fully seated in the valve recession exceeds the valve train wear so the valve lash tends to close up slightly.

Different riders can experience different valve lash decrease/growth depending on the type of riding they do. Like lots of very high RPM high load usage will usually favor valve recession & lash decrease. Whereas lots of short low RPM runs with many cold starts can favor cam train wear & lash increase.

On my KLR I always set the lash to max speciation + next closest shim. (usually a thousandth or two above max specs) as I trash on that engine mercifullyless so they always close up in use. That bike is a pain to set the valve lash as the cams need to be lifted out so setting wide buys me extra time between checks.

On the Ducati same thing, always max spec + as that bike gets ridden very hard at very high RPM's & not using valve springs for valve closer doesn't wear the cam & rocker contact much.

Even on my BMW boxers (I don't own a camhead) I always set to spec +.001" as on MY bikes ridden the way I ride they close up due to valve recession. That also gives me a bit more wiggle room if I put the valve adjustment off until I am doing another service. (I still like to at least check them at around 10K-12K)

As far as where the camhead needs to (or should be) be set to I really don't know yet. That depends on wear traits over miles (if they open up or close up) and how the cam take-up ramps are machined. As long as the valve lift starts somewhere on the cam lobe take-up ramp & is still on the closer take up ramp when closing I doubt it matters one iota where the lash is set as far as engine performance or smoothness as the EFFECTIVE valve opening really isn't effected until the valve lift is well onto the cam's quick lifting part of the lobe & well off of the take up ramp.

That's interesting. I hadn't considered valve recession. Doing a little reading on it, I'm surprised there's much valve recession at all. Is this normal in modern engines, i.e., with hard valve seats, or is it an olihead characteristic, or is it happening to some degree on all engines?
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John in the Metrowest of Massachusetts
2001 R1100RT
- spline failure at 25k miles
- past 45k w/replacement tranny

1982 CB750K "backup bike."

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#749839 - 12/28/11 01:48 PM Re: Valve Adjustment [Re: Whip]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 7770
Loc: Ohio
Afternoon John

Valve recession can happen a bit in all engines that have the valves getting hot then slamming into the seats thousands of times an hour.

It isn't a big issue in modern engines with hardened seats & high alloy valves but it doesn't take much with a tapered valve margin into a tapered seat to lose a thousandth or so on the valve lash.
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#749858 - 12/28/11 04:49 PM Re: Valve Adjustment [Re: dirtrider]
jviss Offline
Member

Registered: 05/19/04
Posts: 777
Loc: Westborough, MA
Thanks; fascinating. You certainly know a lot on these topics.

Oh well, on that note, I went off to the garage to put the 'RT on the lift and adjust the valves. smile

I was amazed that only two of the valves needed any adjustment at all, the top right intake, and the top left exhaust; and even so, they were certainly within the range of the next up or down feeler gauge. I could have left them.

This could be an artifact of the way I adjusted them previously, with my old school feeler gauges, but couldn't have been much off. Now I have pairs of Wurth gauges in .15mm and .30mm.
_________________________
John in the Metrowest of Massachusetts
2001 R1100RT
- spline failure at 25k miles
- past 45k w/replacement tranny

1982 CB750K "backup bike."

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#749861 - 12/28/11 04:54 PM Re: Valve Adjustment [Re: Whip]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 7770
Loc: Ohio
Evening John

If this is on your 1100RT next time you check them rotate the elephants feet to about 4 different places when you check the lash. I have found some that the elephants foot wears (or is built) with enough variation to get looser or tighter by a thousand or so by just rotating to different clockings.
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#749876 - 12/28/11 05:50 PM Re: Valve Adjustment [Re: dirtrider]
jviss Offline
Member

Registered: 05/19/04
Posts: 777
Loc: Westborough, MA
Good idea, thanks. I haven't torqued the valve covers yet, maybe I'll open them up and check.
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John in the Metrowest of Massachusetts
2001 R1100RT
- spline failure at 25k miles
- past 45k w/replacement tranny

1982 CB750K "backup bike."

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#760239 - 02/17/12 09:30 AM Re: Valve Adjustment [Re: Whip]
w2ge Offline
Member

Registered: 01/15/11
Posts: 723
Loc: Voorhees, NJ
semi-off topic for one minute, please..

The exhaust valve rockers are towards the "intake,throttle bodies" side? Correct? or... the intake rockers are towards the front of the bike, i.e. exhaust?
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Phil
2010 R1200RT - 2011 Husqvarna TE310 "Woods Weapon"
NEW SWEDEN BMW RIDERS
iPhone 5>ZUMO 660>SENA SMH10
2014 M-B E350 4MATIC LUXURY
2008 Lexus LS460L Long Edition

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#760249 - 02/17/12 09:52 AM Re: Valve Adjustment [Re: w2ge]
dirtrider Offline
The Oracle
Member

Registered: 06/05/10
Posts: 7770
Loc: Ohio
Originally Posted By: w2ge
semi-off topic for one minute, please..

The exhaust valve rockers are towards the "intake,throttle bodies" side? Correct? or... the intake rockers are towards the front of the bike, i.e. exhaust?


Morning Phil

That wouldn't make sense as the rocker arms that open the valves need to be over the valves then open.

BOTH intake rocker arms & intake valves are REAR of the spark plug

BOTH exhaust rocker arms & exhaust valves are FORWARD of the spark plug.
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Sent from my rotory dial wall phone!

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#760289 - 02/17/12 12:45 PM Re: Valve Adjustment [Re: Whip]
w2ge Offline
Member

Registered: 01/15/11
Posts: 723
Loc: Voorhees, NJ
Thanks DR,

Kinda what I thought.. but was watching JVB video and I "got" confused..
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Phil
2010 R1200RT - 2011 Husqvarna TE310 "Woods Weapon"
NEW SWEDEN BMW RIDERS
iPhone 5>ZUMO 660>SENA SMH10
2014 M-B E350 4MATIC LUXURY
2008 Lexus LS460L Long Edition

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#761047 - 02/21/12 05:17 PM Re: Valve Adjustment [Re: Whip]
Hank in WV Offline
Member

Registered: 06/28/08
Posts: 105
Loc: nrthrn panhandle WV
I just checked the valves on my 2010RT with 8000 mi. The exhaust valves were fine but the intakes were on the tight side. They ranged 007, 006' 005' and 004. Should I change out some semi-spheres or should I be alright for awhile? Are these usually stocked by dealers or do they have to order them?
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67 & 69 Triumphs
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