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: Thu, 12 Nov 1992 14:58:11 GMT

--
In article <1992Nov10.031549.15344@research.nj.nec.com>,
behanna@phoenix.syl.nj.nec.com (Chris BeHanna) writes:
|>Newsgroups: rec.motorcycles.harley
|>Path:
|
ryn.mro4.dec.com!nntpd.lkg.dec.com!decabo.abo.dec.com!pa.dec.com!decwrl!netsys!a
agate!spool.mu.edu!uwm.edu!zaphod.mps.ohio-state.edu!darwin.sura.net!jvnc.net!nj
j.nec.com!news
|>From: behanna@phoenix.syl.nj.nec.com (Chris BeHanna)
|>Subject: Re: Riviera 4 valve heads
|>Message-ID: <1992Nov10.031549.15344@research.nj.nec.com>
|>Followup-To: rec.motorcycles.harley
|>Sender: behanna@syl.nj.nec.com
|>Reply-To: behanna@syl.nj.nec.com
|>Organization: NEC Systems Laboratory, Inc.
|>References: <1992Nov5.173341.26529@engage.pko.dec.com>
|><1992Nov7.011018.3973@tcsi.com> <1992Nov9.210904.18631@engage.pko.dec.com>
|>Date: Tue, 10 Nov 92 03:15:49 GMT
|>Lines: 42
|>
|>In article <1992Nov9.210904.18631@engage.pko.dec.com>
|>dehahn@strokr.shr.dec.com writes:
|>>--
|>>In article <1992Nov7.011018.3973@tcsi.com>, markk@tcs.com (Mark Kromer)
|>writes:
|>>|>
|>>|>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.
|>
|>	7000 rpm with 4.75" stroke = 5500+ fpm piston speed.
|>	8000 rpm with 4.75" stroke = 6300+ fpm piston speed.
|>
|>	How in the hell do you hold that motor together?  Most designs
|>that have reliability in mind (even Japanese motors that rev to 14000 rpm)
|>do not exceed 4500 fpm.
|>

I had a reply all written up and the server ate it. One more try.

Using the theories above every stroker should have blown up the minute it
hit redline. Even the rice rocket riders don't ride at 14 grand all day long.
What you don't mention about piston speed is that its consequence to a
motor's longevity is heat, which can be dissipated if designed and ridden
properly. It's too bad you're so far away, I'd show you some pistons out of
a five year old 98" FX which was ridden all over the Northeast and has had
its share of strip time during the last 25K miles. They look like any 25K mile
piston. The bike still ran fine, it was getting a bit tired. The pistons in my
motor have been modified to flow more oil to the piston lands, skirts and
wrist pins.

|>	All this assuming you have a 4.75" stroke.  Shorter strokes
|>will scale down the piston speed linearly, but you're still spinning
|>that engine awfully damn fast, especially considering the mass of
|>the reciprocating parts.
|>
|>Inquiring (and maybe a bit jealous :-) minds,

Yes, 4 3/4" stroke by 3 5./8" bore. The flywheel assembly is significantly
lighter than stock.

CdH

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