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RE: [turbobike] Compression Ratio

Bryan (bgoodwin@iquest.net)
Tue, 09 Nov 1999 14:31:58 -0500

I wouldn't recommend boring your sleeves too thin, especially if you intend
to build much boost. They will egg-shape in short order. I would say that
you should try to maintain at least .080" wall thickness, preferrably
.100-.120".

You should not bore your cylinders until you coat the pistons. That way,
you'll know for sure that you have the right clearance.




At 12:21 AM 11/9/99 -0800, Abraham Mara wrote:
>weisco definatly sells a 1428 kit for the KZ-1000s, I'd have one were I not
>so broke.  :-)  I AM ordering pistons this week, from them...  73 mm, the
>last size on the stock sleeves.  Are the chrome pins the stock ones they
>give you in their kits?  Does anyone know what those cyclender and piston
>coatings cost to get done?  How thick are the coatings (i.e. do I need to
>bore the cylender any bigger to fit it?)  Thanks in advance
>		-Abe.
>
>-----Original Message-----
>Hi Steve,
>
>For a street ridden 2 valver on pump gas I would go no higher than 8:1.
>Those
>Kaws will give you fits with detonation, especially if you want to run any
>appreciable boost.  See if you can come up with a 1428 kit to make up for
>the
>reduced compression.  I know the Wiseco catalog only lists up to 1260, but
>they
>do exist.  I like the MTC pistons and their standard thickness hard chrome
>pins
>(even the small 17mm versions for the older Kaws) work well until you really
>turn the heat up (like 300 Hp).  The new Wiseco pieces are very good,
>though.
>They solved their problem of wrist pin galling and the pistons have gotten
>much
>better.  Use the heavy wall hard chrome pins from Wiseco if you go that way.
>
>Make sure you take the squish out of the motor.  Run a thick base gasket to
>put
>the piston squish band height at least 0.050" below the cylinder top
>surface.
>You might be able to run the 10.25:1 pistons and use a very thick base
>gasket to
>both reduce the compression and take out the squish.
>
>One option is to go with two plugs per cylinder to reduce the flame travel
>path.
>You can then retard the timing a bunch without losing anything.  The
>drawback is
>that it tends to weaken the head, and you have four coils and eight plugs &
>wires to deal with.  It makes a nasty sound when the head splits open down
>the
>center.....trust me.
>
>The oversized valves will help but you'll need porting to go with them.
>Your
>'83 will make a nice cylinder head.  I have a good source if you are
>interested.
>
> Your stock cams will work well.  Several six second funnybikes use those
>exact
>cams.
>
>Run a big oil cooler, or else run two smaller ones if they fit better.
>Don't
>block the airflow to the head and cylinder with the cooler.  I took 40
>degrees
>out of the running oil temp. on my FJ with the addition of a second cooler,
>and
>gained oil pressure in the process.  I mounted it down on the chin fairing,
>right in front of the water injection tank.  You'll need one of those on
>your
>bike for sure as well.
>
>It sounds like others have had good experiences with those thermal barrier
>coatings.  I've never tried them myself.
>
>Good luck.
>Bob
>
>
>
>
>
>"Steve Leonard" <sleonard@buffnet.net> on 11/05/99 02:20:18 PM
>
>To:   turbobike@natvideo.com
>cc:    (bcc: Bob Shammas/EQA/Nsk-Corp)
>Fax to:
>Subject:  [turbobike] Compression Ratio
>
>
>
>
>I am building a 1983 GPZ1100, with a MoTeC M4 engine management system and a
>IHI-RHB5 turbocharger.....
>
>Since this a 2-valve motor and I want it to be some what streetable
>(preferabably pump gas), what compression do you recemmend, (1260cc), to
>reduce
>detonation I can retard the timing as boost increases with the MoTec
>software.
> Also will any great benefit be obtained with 1mm over-size stainless intake
>and
>exhaust valves?
> Is there any advantage to having the combustion chamber and pistons
>"coated"
>with the thermal barrier compounds that are available?( I live about 10miles
>from a place that does it)
>
>regards
>Steve
>
>
>
bgoodwin@iquest.net
FZR1000 turbo EFI
(aka The Money Pit)