From: dehahn@strokr.shr.dec.com (chris dehahn)
Subject: Re: Riviera 4 valve heads
Reply-To: dehahn@strokr.shr.dec.com
Organization: Digital Equipment Corporation
Date: Mon, 9 Nov 1992 21:09:04 GMT

--
In article <1992Nov7.011018.3973@tcsi.com>, markk@tcs.com (Mark Kromer) writes:
|>Newsgroups: rec.motorcycles.harley
|>Path:
|
engage.pko.dec.com!nntpd.lkg.dec.com!news.crl.dec.com!pa.dec.com!decwrl!uunet!tc
csi.com!sparcplug!markk
|>From: markk@tcs.com (Mark Kromer)
|>Subject: Re: Riviera 4 valve heads
|>In-Reply-To: dehahn@strokr.shr.dec.com (chris dehahn)
|>Message-ID: <1992Nov7.011018.3973@tcsi.com>
|>Originator: markk@sparcplug
|>Sender: markk@tcs.com
|>Reply-To: markk@tcs.com (Mark Kromer)
|>Organization: Teknekron Communications Inc.
|>References: <1992Nov3.014514.6201@icomsim.com>
|><1992Nov5.173341.26529@engage.pko.dec.com>
|>Date: Sat, 7 Nov 1992 01:10:18 GMT
|>Lines: 41
|>
|>In article <1992Nov5.173341.26529@engage.pko.dec.com>, dehahn@strokr (chris
|>dehahn) writes:
|>
|>>The heads work. They are NOT a bolt on affair. How long they will last is
|>very
|>>questionable at this point. The cam is almost completely square, it's gotta
|>>beat the snot out of the valve seats.
|>
|>Valve and seat life is one of the advantages of the 4 valve design.
|>The valve to seat contact area is much greater for two small valves
|>than for one large one.  This allows the two valve springs to exert a
|>much greater closeing force than one while not dmamging the seats.
|>This allows you to run a lumpy cam or higher red line.
|>

All fine and dandy in theory but have you checked out this setup with 
your own eyes? You have to see it to believe it. There's a heck of a lot
of valve spring pressure for a much smaller valve seat area, all being 
pumped up and down  in a very snappy fashion. Time will tell.

|>>IMO you're much better off going with a more traditional straightforward
|>>approach.
|>>
|>>ignition - Dyna S single fire
|>>Coils - Dyna
|>>Carb - S&S 'E'
|>>Cam - depends if Sportster or Big Twin
|>>Pistons - S&S (TRW), Arias or Wiseco 10:1 comp
|>>heads - ported and flowed by someone that knows what they're doing
|>>Pipes - pick 'em
|>>
|>>This should get you in the neighborhood of 80hp at the rear wheel.
|>
|>IMHO, judging from the cam profile, the Riviera design is a cylinder
|>head looking for a bottom end to take full advantage of its breathing
|>capacity and rev capabilities.  I'd like to see a little less cam and
|>a lot higher red line.  Does anyone know what the reliable rev limit
|>is for a built bottom end?  I'd like to try punching out the bore and
|>shortening up the stroke to see if I could get one to spin at 8000 -
|>9000 rpm all day.  70 - 80 HP/liter or more at the wheel might be
|>achieveable.  I think the upper bound for a streetable large
|>displacement twin is over 100 HP/liter at the rear wheel (the fastest
|>Ducatis).  Any thoughts?
|>

Yea, I think it'll turn a Big Twin harley into a Jap bike. All power, no
torque. My motor revs to 8 grand although it's undercammed to
redline at 7 grand for the street. Why give up the torque for another
1,000 rpm? The torque is what beats the jap bikes. 

As for 100hp at the wheel, that's easy. More is possible. When mine
hits the dyno I'll let you know.

CdH

<<<<<<<<<<<<   Ninety eight....don't be late  >>>>>>>>>>>>
Chris deHahn....CdH....Digital Equipment Shrewsbury MA USA
dehahn@strokr.shr.dec.com