New Hexhead Head Design

[Ken H.]

This month's MCN has a cutaway of the new head design with true DOHC on the new HP2 Sport. Longer cam chains turning two cams with finger followers to each set of valves. Redline goes up to 9500 RPM. Wonder how valve adjustments will now be done? Hard to tell in the drawing. I wonder too does this make the overall motor even wider, or does it all manage to tuck under the same depth valve cover as before? Looks like it might be about the same. It's also back to being a single sparker. 130 claimed HP.

 

The drawing didn't scan in all that well but here is what I could get:

 

[BMWRich58]

Wonder how valve adjustments will now be done?

 

Bucket n shim...?

[s3steve]

Here's a link with a color pic.

 

http://www.autoblog.com/photos/bmw-hp2-sport/423943/full/

[Highway41]

That motor in an RT will be my next bike purchase. Hope it comes in dark graphite.

Bill

[SageRider]

Ken, are you sure it's a single sparker? Isn't that a second plug partially obscured by the upper rear intake valve spring?

[Deans BMW]

The motor is actually 20 mm narrower over all. That motor in the 24 hour Bol D Or and the just completed 8 hour where the R1200 HP Sport placed 7th overall is running 140 HP. For these endurance races, the red line is lowered to 9,000 R's.

 

 

[duckbubbles]

They say it's a single sparkler. It may use shim on top of valve as it looks like the shaft for the finger follower is designed to move to the side when the locating clip is removed.

I also read that it has radially dispersed valves like some Honda dirt bikes and the MV Agusta F750/1000 and dual throttle bodies the cylinder. Detuned to 120HP for the RT, etc.?

What I read was that it also has sliders on the valve covers that can act like knee sliders. Only on smoooooth surfaces, I think.

I am surprised that BMW may be showing us the next development of the boxer and comng sooner than expected.

Keep it coming.

 

Frank

[jaytee]

So why is this labeled a K1200S ??? Isn't this clearly an "R" ???

 

 

JT

[duckbubbles]

So why is this labeled a K1200S ??? Isn't this clearly an "R" ???JT

 

You DARE question the media??? It MUST be a K!!

 

Just noticed- It's BMW Motorad.

 

Frank

[Boffin]

So why is this labeled a K1200S ??? Isn't this clearly an "R" ???

 

 

JT

 

The pics are from the website www.k1200s.de

 

Andy

[s3steve]

Here's the link for the full story.

 

http://www.autoblog.com/2007/10/03/bmw-introduces-their-new-r1200s-based-hp2-sport/

[Ken H.]

Ken, are you sure it's a single sparker? Isn't that a second plug partially obscured by the upper rear intake valve spring?

Think that is the central main plug. The second lower plug that comes into the head from the bottom on the current hexhead is gone.

[RFW]

Wonder how valve adjustments will now be done?

 

Bucket n shim...?

No, he said it was "finger follower".

[SageRider]

Ken, are you sure it's a single sparker? Isn't that a second plug partially obscured by the upper rear intake valve spring?

Think that is the central main plug. The second lower plug that comes into the head from the bottom on the current hexhead is gone.

 

[Ken H.]

Oh, yeah, I see what you're referring to now. I don't know. I'm just repeating what has been published that says it's a single sparker. Could be right, could be wrong.

[SageRider]

It's always fun to speculate... I should be a reporter!

[Ken H.]

Here's a link with a color pic.

 

http://www.autoblog.com/photos/bmw-hp2-sport/423943/full/

It would be interesting to see a cut-away of the other side where the chain pulls from the top. Must have some kind of stationary chain roller or something to make it to the top cam. Can't imagine the typical plastic chain rails used in the past would be enough to keep timing.

[TedG]

Oh, yeah, I see what you're referring to now. I don't know. I'm just repeating what has been published that says it's a single sparker.

 

The December issue of Roadracing World says the bike is a single plug per cylinder design. Too bad it's going to cost more than I can afford.

[bakerzdosen]

Oh great, now we're gonna need ANOTHER forum.

[Highway41]

The "Twin Cam" forum?

[duckbubbles]

The "Twin Cam" forum?

 

Or maybe the "Four Cam" forum.

 

Frank

[Eschelon1]

The motor is actually 20 mm narrower over all

 

 

Did they shorten the stroke?

 

[Don_Eilenberger]

They say it's a single sparkler. It may use shim on top of valve as it looks like the shaft for the finger follower is designed to move to the side when the locating clip is removed.

It's exactly the same design as BMW has used on the S54 engine used in my M3 (and the MZ-Coupe). The finger follower moves to one side and the shim is lifted out with a magnetic tool. Nice design.. I'm very familiar with adjusting the 24 of them on my M3 :-) Given the similarity in design it wouldn't surprise me to find they use the same shims (the shim kit is around $400.. but that's less than BMW wants to adjust the valves on an M3, so..)

Frank

[Don_Eilenberger]

It would be interesting to see a cut-away of the other side where the chain pulls from the top. Must have some kind of stationary chain roller or something to make it to the top cam. Can't imagine the typical plastic chain rails used in the past would be enough to keep timing.

Just guessing - but a small counter sprocket (gear or chain driven) inside the engine could be used to change the direction the right side chain moves in (left counterclockwise, right clockwise) - and no reason the right side cams couldn't turn the other way (just need the lobes designed to do it..) so the chain design at the head could be the same. Be lots simpler than an chain-idler in the head.

[Deans BMW]

The bore and stroke are the same as in the R1200 Hexhead engines.

[1analguy]

The "Twin Cam" forum?

 

As usual, BMW's late to the party again: Harleys have been "Twin Cams" since 2000...

[r2d2]

this bike was tested in november issue of bike magazine - its fitted with ohlins rear and marzocchis forks front.

 

"the spring rates and damping seem all to cock" wrote the tester, "cant brake and handle bumps at the same time. maybe its not cut out for yorkshire, ok on smoother roads"

 

maybe bmw should put esa and the rest of the stock parts on this bike - my rt is great in yorkshire :-)

[Paul Mihalka]

As usual, BMW's late to the party again: Harleys have been "Twin Cams" since 2000...

That's one of my gripes against Harley, it is a scam. To me, and to anybody who knows a little bit about the inside of a engine, a Twin Cam is one that has two camshafts in the cylinder head. Calling it a Twin Cam because it has two cams down in the crankcase and using long pushrods to activate the valves is twisting the truth.

[Highway41]

Had a '98 Twin Cam FXD that I traded in on the GT. Was the first one on Adamec's floor.

As Paul says, it is a misnomer as the cams are not on top of the heads and actuated the valves via pushrods. It was a great bike though, especially around town.

Bill

[duckbubbles]

That's one of my gripes against Harley, it is a scam. To me, and to anybody who knows a little bit about the inside of a engine, a Twin Cam is one that has two camshafts in the cylinder head. Calling it a Twin Cam because it has two cams down in the crankcase and using long pushrods to activate the valves is twisting the truth.

 

So using Harleyspeak, the Sportster would be a Four cam or Quad cam. Just paintshakers.

 

Frank

[Rich06FJR1300]

so to adjust these valves i take it you have to remove the camshafts? i wonder what the interval will be...still at 6,000 miles, should be longer if its shim under bucket. We shall see.

[duckbubbles]

so to adjust these valves i take it you have to remove the camshafts? i wonder what the interval will be...still at 6,000 miles, should be longer if its shim under bucket. We shall see.

 

Everybody's just speculating at this point, we really don't know jack...but, from what I can see in the graphic representations, it appears that the cam follower may slide to the side once that retaining clip is released to access a shim on top of the valve stem. One responder stated that the setup looked just like what is on his BMW car and that is how it works in that application.

 

I'll say it again, we really don't know jack about this yet, it's all speculation. And some of us like that just fine.

 

Frank

[Wiley]

As usual, BMW's late to the party again: Harleys have been "Twin Cams" since 2000...

That's one of my gripes against Harley, it is a scam. To me, and to anybody who knows a little bit about the inside of a engine, a Twin Cam is one that has two camshafts in the cylinder head....

 

Isn't that referred to as an *overhead* cam?

[R4ND0M_AX3]

Isn't that referred to as an *overhead* cam?

Or, in the case of the HP2 Sport, dual overhead cams aka DOHC.

[SANTA]

Ken;

 

i saw pictures somewhere of a section and i beleive there is a second spark plug but it now located at the top of cyl.

[gmueller]

I believe it is just one Sparkplug located smack in the center of the 4 Valves.

[SANTA]

I cannot find the info i thought i saw, so i stand corrected...

 

1 plug...

[DoctorC]

Let me see... we used to be able to purchase high performance dual spark heads (oops, wrong forum)... and maybe now can purchase high performance single spark heads (I know.... new pistons and stronger crank, etc...) Just dreaming...

 

Steve C

R1200ST