rtbain
Expert Class
old, fat and slow
Posts: 244
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posted March 14, 2010 09:58 AM
Stroking a motor - be nice
I am seriously considering stroking my ZX14 motor. It is currently running +2mm pistons with CompetitionCNC stage II head. The bottom end is solid with Carrillo rods. I am considering a +5mm crank.
It will be awhile before I can save the coin to do this so I want to begin with research. Any and all ideas are welcome. The bike will see 90% track use, mile and LSR, normally aspirated. I would prefer to keep stock rods but would appreciate a discussion of different rod lengths on torque.
I would also like to keep piston speed within reasonable levels, by that I mean I won’t have to change pistons every build.
I PROMISE to take pictures of Jim’s stage II head this time.
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Randy
   
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shiphteey
Needs a job
Posts: 2529
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posted March 14, 2010 11:02 AM
Do you have a specific speed goal with the stroker? What gains are you hoping to achieve over your present build?
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Gemini Motorcycles
Topping out everything from Ninja 250s to nitrous ZX-14s.
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rtbain
Expert Class
old, fat and slow
Posts: 244
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posted March 14, 2010 11:55 AM
Good questions. No specific speed goal. Looking for a moderate build, not a hand grenade that has to be rebuilt after every event.
For reference I consider my current build from stock moderate:
+2mm over pistons running about 14:1
CompetitionCNC head, +1mm os valves, custom grind cam, (degreed) APE springs and retainers.
APE studs
Bottom end is stock save Carrillo rods.
Brock Pipe (AlienHead)(baffle removed)
PCIII with ignition module (+500 RPM rev limiter)
The current build is a very strong motor, but speed is addictive. I plan on purchasing a set of 50mm throttle bodies when Jim makes them available.
Sure I would like to set records, but I am old and fat so the 95lb jockeys will always win. I am looking to improve my current platform while remaining naturally aspirated. I am in it for the challenge of doing my personal best within a real world budget. I enjoy tuning and racing, as much for the people involved as going fast.
I plan on making Loring and Bonneville but will remain mostly in Texas. Loring is a strong possibility this year; Bonneville is a maybe for 2011.
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Randy
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Shane661
Needs a life
Posts: 11494
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posted March 14, 2010 12:06 PM
The 1534 seems to be a solid platform. But the bigger and more powerful you go, the less of that stocker reliability you will have.
My suggestion is to spend a season riding and racing this one. Then make your decision.
Of course, I was also the guy who suggested a full season on the stock motor. 
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rtbain
Expert Class
old, fat and slow
Posts: 244
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posted March 14, 2010 12:10 PM
Shane,
Sound advice. I will spend this season on this motor. But I'm looking ahead and want to find out the best route to take. Once the design is decide on I have to save the money to complete the build.
Shoot I haven't even made one event on this motor yet. I bust its cherry at the March Texas mile. WooHoo!
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Randy
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KZScott
Needs a life
high on speed
Posts: 7235
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posted March 14, 2010 03:20 PM
do a 4mm. I think you can get a 2mm head gasket to compensate and keep stock length rods
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01 ZX-12R 8.84 @ 156.3 no bars, DOT tires. Pump Gas, NA.... turbo 8.47 @ 164.
00 ZX-12R 8.62 @ 165.2 no bars, slicks, Pump Gas, 55 shot.... turbo 8.32 @173
00 ZX-12R Fastest NA Kawasaki in the world 1: 222.046 1.5: 226.390 Loring AFB
00 ZX-12R street turbo 1: 227.9 1.5: 234.1 Loring AFB
00 ZX-12R LSR turbo 1: 263.1 1.5: 266.5 Loring AFB Worlds fastest ZX-12R
CMG Racing RCC Turbos
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WRECKSHOP
Expert Class
Posts: 359
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posted March 14, 2010 11:38 PM
I wonder which would be better, a .2mm head gasket or .2mm offset pistons ?? Which way would presumbly make MORE POWER ???
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rtbain
Expert Class
old, fat and slow
Posts: 244
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posted March 15, 2010 02:21 AM
Power wise it seems to be a wash to me. I have some concerns about the thicker head gaskets, but that may be ingorance talking. Would a thicker gasket be more prone to failure?
For that matter would a piston pin off set affect the number of piston rings?
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Randy
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Shane661
Needs a life
Posts: 11494
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posted March 15, 2010 03:59 AM
From what I understand, the standard 1534 setup loses one set of rings.
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted March 15, 2010 04:36 AM
you want the squish to be tight no matter what. Never loosen it up regardless of what compression ration you are running. It's Important to the chambers resistance to detonation.
On a street bike you want the second oil scraper ring. On a race bike you don't need it, so raise the pin and loose the second oil ring.
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Y2KZX12R
CompetitionCNC.com
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06redzx14
Pro
Posts: 1022
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posted March 16, 2010 11:09 AM
if you go 4 mil stroke you won't have to make clearences to your cases. I think a 2 X 4 is 1508cc
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06 alien head, no flies, PC+hub, 16/45 44 43, air shifter, dry shot
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krexken
Zone Head
Posts: 732
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posted March 16, 2010 11:24 AM
I'd go with a shorter rod. Sell your Carillos to help pay for new ones.
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Shane661
Needs a life
Posts: 11494
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posted March 16, 2010 02:05 PM
2x4 is a 1510.
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dubious
Needs a life
Needs more time to ride!
Posts: 8442
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posted March 21, 2010 04:23 AM
quote:
you want the squish to be tight no matter what. Never loosen it up regardless of what compression ration you are running. It's Important to the chambers resistance to detonation.
On a street bike you want the second oil scraper ring. On a race bike you don't need it, so raise the pin and loose the second oil ring.
the 1534 eliminates the 2nd compression ring, is this what you are referring to Jim?
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natural selection.....
destiny will overcome intervention.
Some are not worthy of the effort.
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rtbain
Expert Class
old, fat and slow
Posts: 244
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posted March 21, 2010 05:48 AM
I am a bit confused; Muzzy’s 5mm stroker appears to use stock length rods.
I don't mind losing the second oil ring as this will be a 95% track bike so offset pistons are no problem.
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Randy
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Shane661
Needs a life
Posts: 11494
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posted March 21, 2010 08:23 AM
Yes, the Muzzy kit uses stock length rods. But you also lose 1 set of rings because the wrist pin is moved up.
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted March 23, 2010 06:10 AM
 Edited By: Y2KZX12R on 23 Mar 2010 14:14
quote:
quote:
you want the squish to be tight no matter what. Never loosen it up regardless of what compression ration you are running. It's Important to the chambers resistance to detonation.
On a street bike you want the second oil scraper ring. On a race bike you don't need it, so raise the pin and loose the second oil ring.
the 1534 eliminates the 2nd compression ring, is this what you are referring to Jim?
Yes.
But the 2nd ringisnt a compression ring and doesnt effect compression at all. Its really an oil scraper ring designed to scrape the cylinder wall of oil so the top ring doesnt "float" on oil.
If the second ring was actually a compression ring and compression built up between the rings the top ring would become unsettled on the ring land and compression would cause the ring to flutter. This is why you open up the 2nd ring end gap more than the top ring end gap. With a nitrous motor you should open up the 2nd ring end gap even more.
Of course the inertia of the top ring can also cause flutter but the oly way to fix that is to use a lighter weight ring.
Gas porting can also help with inertia inducedflutter as well.
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Y2KZX12R
CompetitionCNC.com
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rtbain
Expert Class
old, fat and slow
Posts: 244
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posted March 23, 2010 11:12 AM
Now the big question. Who do I go to for crank work and pistons?
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Randy
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Shane661
Needs a life
Posts: 11494
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posted March 23, 2010 11:16 AM
Marine Crank and CP pistons.
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Y2KZX12R
Needs a job
CompetitionCNC.com
Posts: 3762
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posted March 26, 2010 04:10 AM
quote:
Marine Crank and CP pistons.
+1
CP is making me a set of custom pistons right now.... quite different from any standard offerings.
And Marine is doing a weldup for me also.
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Y2KZX12R
CompetitionCNC.com
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Pretty Fast
Expert Class
Posts: 116
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posted March 26, 2010 05:12 AM
rtbain, I currently have the 2 mm over bore and head work myself and thinking about putting the gas to it. Have u had a chance to dyno yours yet and if so, what kind of power are u making?
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