gsxrassassin
Expert Class
Posts: 225
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posted February 28, 2010 01:54 PM
Crank Balancing
Couldn't find exactly what I was looking for through the Search option.
Putting the plan together for next winter's project on the ZX-14. Going with a 2mm bore (1417cc), Web Cams, Crank Balance (switching balancers with blank shafts), Muzzy pipe, Mid-range Velocity Stacks. My tuner tells me the head is good enough that I really don't need to put any work into it.
Flies are already out, PCIII is already in and I'm currently running a Boz Moira pipe (will come off at the end of upcoming riding season).
I need input from folks who have had the balancers removed from their motors. How do you like it? Does it make much of a difference? Secondly, I'm going to have Marine balance the crank for me. Does anyone know how much they charge for balancing the 14's crank? Thanks.
Fast
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Compton
Zone Head
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posted February 28, 2010 03:38 PM
for marine, to lighten and balance a 14 crank is around 300 with return shipping.
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Shane661
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posted February 28, 2010 03:41 PM
 Edited By: Shane661 on 28 Feb 2010 23:41
As far as I know, the balancers remove a secondary imbalance/harmonic. Balancing the crank will not take the place of the balancing shafts, in that respect.
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gsxrassassin
Expert Class
Posts: 225
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posted March 01, 2010 04:52 PM
quote:
As far as I know, the balancers remove a secondary imbalance/harmonic. Balancing the crank will not take the place of the balancing shafts, in that respect.
Will any damage be done to hurt the motor without these the balancers? Thanks.
GSXR
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Y2KZX12R
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posted March 01, 2010 06:01 PM
The term "balancers" is misleading. They don't actually "balance" anything.
They absorb secondary harmonics that are perceived by the rider as a buzzing vibration often in the handlebars, foot pegs etc.
Single plane crankshafts (most in-line 4 cyl engines) are neutral balanced. But because all 4 pistons have zero velocity every 180 degrees of crankshaft rotation and there arent any pistons mid stroke like on a V8 to help counteract the secondary harmonics, the engine design is prone to stronger secondary harmonics. Something a V8 engine with a dual pane crankshaft has much less of by design.
What actually is going on is the crankshaft rotational speed is speeding up and slowing down every time the pistons go from TDC/BDC to mid stroke.
So you may feel more secondary vibration from the engine if you remove the shafts. But it in no way will hurt the engine and no re balancing is required.
If you have the crank lightened then yes you will need to re balance the crankshaft to get it neutral again. But the piston and rod mass don't play into the balancing of a single plane crankshaft because they cancel each other out.
Make sense?
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smokinZX14
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posted March 01, 2010 06:07 PM
yup ...
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ZX14Mike
Zone Head
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posted March 01, 2010 06:27 PM
OK.........so do you guys think lightening the crank would help performance on the ZX14?...........i'm thinking quicker reving would equal quicker acceleration provided you didnt get massive wheel spin off the line?
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Y2KZX12R
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posted March 01, 2010 07:03 PM
quote:
OK.........so do you guys think lightening the crank would help performance on the ZX14?...........i'm thinking quicker reving would equal quicker acceleration provided you didnt get massive wheel spin off the line?
It would alow the engine to rev quicker. But the bike wouldnt launch as hard for a given RPM.
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smokinZX14
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posted March 01, 2010 07:06 PM
I would not lighten it , but i would have it knife edged to help with windage ..
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Tampa Bay , FL .. Brocks Performance Dealer ..
Gen 2 ZX14R Best ET 8.43 , Best MPH 164.95
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gsxrassassin
Expert Class
Posts: 225
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posted March 02, 2010 07:36 AM
Thanks a million guys. I really appreciate it. I thought long and hard about doing the head but I'm not at the track with mine. I'm mainly on the streets and highways of Chicago so I'm not sure if I'll get out of it what I'd put into it - know what I mean?
If I was shooting for that extra .02 seconds to beat a guy for money or points then doing the head would make a ton of sense. But mainly I'm running with my friends up and down I-57, I-94, Lakeshore Drive and out I-290. I think the stock head is more than enough. I'm 97.5% convinced of this but as always, I welcome input from other riders/racers. Thanks.
GSXR
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dubious
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posted March 02, 2010 09:22 PM
I bike with light crank will also slow much quicker when decellerating due to less rotating inertia...and might not shift as well with the revs dropping quicker on clutched gear changes
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gsxrassassin
Expert Class
Posts: 225
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posted March 03, 2010 11:56 AM
quote:
I bike with light crank will also slow much quicker when decellerating due to less rotating inertia...and might not shift as well with the revs dropping quicker on clutched gear changes
Does balancing the crank mean that it will be that much lighter? I know they'll have to remove something but how much you think will come off?
GSXR
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gsxrassassin
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Posts: 225
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posted March 03, 2010 12:01 PM
By the way - the guy's who working on my GSX-R1000 and will be working on my ZX-14 is a cat named Eric at Rev'd Up Motorsports in Dekalb, Illinois.
He's a young guy but his knowledge is deep. He's great to work with, doesn't mind giving you all the pros and cons of what you have planned for your bike and is very reasonable on the price. He's got some decent industry contacts too. I got his info from another member on this site and that member was right - Eric's a great tuner.
GSXR
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