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TOPIC: Re:high compression pistons
#420212
ahamay (User)
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Re:high compression pistons 3 Years, 1 Month ago  
ahamay wrote:
mkayx wrote:
i was very happy with the wiseco 10.5:1 pistons not so much with the je 10.25:1 pistonsWhy is that? the difference between 10.25 and 10.5 performance wise really should be negligible.
Hmmmmmm, That's what I thought.
 
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#420217
mkayx (User)
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Re:high compression pistons 3 Years, 1 Month ago  
the wiseco are lighter then the je so you loose less power at the crank the wiseco are also polished to a higher finish so less carbon build up the wiseco also have a smaller skirt so there is less friction less friction means less heat which means less power loss also the wiseco have bigger std oil drain back holes and forced pin oiler holes not to mention they cost less
 
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Last Edit: 2011/09/15 22:42 By mkayx.
 
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#420234
old dog (User)
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Re:high compression pistons 3 Years, 1 Month ago  
Some very good points made here.If you are going to go for performance, then you have to spend the cash for the full deal.To go half way, you will waste your time and money. As mentioned heads and pistons without the cams,carb, intake, pipes,proper ignition,etc you get about 60% of there full potential.If you are going to up your carb on the stock motor go to the 42.I ran the 45 with for awhile and found no advantage.
Some have posted they would not do it again??? Agree that I would not done it to a 1600. If I had paid full price for mine I would also agree. I bought this off the floor for $7200. None of the dealers here would drop below 11K. So that left me with 4K to play with.
It's all a choice, buy a fairing, custom paint, stereo, air ride , bling, etc. You can spend more.
I love to sandbag, I don't let on,..great fun blowing the doors off some of the " other brands" and telling them "no its just a Yamaha"

so to answer your question No!! So when you read " I put a 45 carb, pipes, big heads, etc and "it runs like a raped ape" ...negative!!

bill
 
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110 cu in., PR/JE 10.25:1 HC pistons, PR Cam, PR adjustable push rods, PR stage II ported heads (2mm oversize valves)
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#420337
huskerbob (User)
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Re:high compression pistons 3 Years, 1 Month ago  
Jade68454 wrote:
COME ON JOHN your bike is BADASS it has the High Compression Pistons let here from ya
 
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Last Edit: 2011/09/16 10:44 By huskerbob.
 
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#420349
ahamay (User)
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Re:high compression pistons 3 Years, 1 Month ago  
mkayx wrote:
the wiseco are lighter then the je so you loose less power at the crank the wiseco are also polished to a higher finish so less carbon build up the wiseco also have a smaller skirt so there is less friction less friction means less heat which means less power loss also the wiseco have bigger std oil drain back holes and forced pin oiler holes not to mention they cost lessIf the piston weight is significantly lighter or heavier I would strongly advise to have the rotating assembly dynamically balanced. If you are worried about friction from the piston skirts, have them coated with teflon or the new ceramic low friction material. If the engine is balanced you lose less power by eliminating the parasitic losses through vibration. I had one drag racer I never could catch even though our cars were almost identical. Eventually I found out that his big secret was an outfit that dynamically balance his engine. After my next tear down and rebuild we split the runs almost 50-50 from then on. If you doubt the power of having your engine in balance find somebody that rebuilt a Chevrolet 400 cubic inch engine and had it blow the crankshaft out of the bottom of the engine. The 400 is balanced on the exterior via the fly wheel and the harmonic balancer. Some people don't know that and slap on parts for a 350. When you are building an engine you want to have around for a long while dynamic balancing is a good investment.
 
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#420352
slothy (User)
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Re:high compression pistons 3 Years, 1 Month ago  
only way i can see hc pistons being worth it is having it apart already, and since your there do em, or doing cam/heads/pistons
 
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#420364
ahamay (User)
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Re:high compression pistons 3 Years, 1 Month ago  
slothy wrote:
only way i can see hc pistons being worth it is having it apart already, and since your there do em, or doing cam/heads/pistonsOr you really are going to race it on a regular basis.
 
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#420367
mkayx (User)
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Re:high compression pistons 3 Years, 1 Month ago  
balancing and bluerinting is very important.
but this is about the hc pistions many have them done when the recall is done i did mine when i had the head and valve work taken care of.
another old school racing tip is have the valves triple cut even if you get the over sized valves.
 
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Last Edit: 2011/09/16 15:13 By mkayx.
 
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#420390
ahamay (User)
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Re:high compression pistons 3 Years, 1 Month ago  
mkayx wrote:
balancing and bluerinting is very important.
but this is about the hc pistions many have them done when the recall is done i did mine when i had the head and valve work taken care of.
another old school racing tip is have the valves triple cut even if you get the over sized valves.
Three angle valve jobs always and especially with oversize valves. If you are going for performance you need to match your compression with the type of cam you are going to run. Just look at a JEG'S catalog in the cam section and they will tell you this cam works best with this level of compression. Cars and motorcycles are the same in that respect. If you're gonna do it, do it right. Run with the big dogs or stay on the porch. Just tossing HC pistons in your engine may or may not get you more performance. If you don't match the weight of the HC pistons with the stock pistons you could do some damage. This would at least give you a rudimentary balance that Yamaha calculated. If their abacus was working that day and no other production changes or variations occurred the balance should be reasonably close.
 
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