12.3:1 JE Pistons vs stockers

[Quasar]

For those who may be interested, here are a few pics of my 12.3:1 81mm (stock bore) JE Pistons beside my stock 99 Hayabusa pistons. There's also a picture of them installed in the cylinders when I was putting the engine back together.

[Tybalt]

Are you going to run 2 intake cams? a little more peppy, need some adjustable cam sprockets as well, but a very nice performance mod

[Quasar]

Are you going to run 2 intake cams? a little more peppy, need some adjustable cam sprockets as well, but a very nice performance mod

I did better than just using two OEM intake cams. I'm into a more complete package when performance building. Two OEM intake cams just wouldn't be enough.

I installed a set of .378"/.330" Web cams with APE 53 pound valve springs and APE Titanium retainers to provide the necessary "valve free travel" and also used APE adjustable cam sprockets. I degreed the intake @105 and exhaust at 107 lobe centers. It's got plenty of pep from idle through redline and it's the reason I can easily enjoy much taller gearing. I typically use 19/43 gearing (which is 3.815% taller than stock), but I even go as tall as 19/41 gearing, which is 8.289% taller than stock. This taller 19/41 gearing allows speeds of just over 97 MPH @5,000 RPM. So, lower RPM still produce some fairly fast highway cruise speeds.

I love making use of power at low through mid RPM and while I couldn't be happier with my engines' high-end pull, I generally don't race my engine up in its high RPM these days to avoid acquiring the attention of police in hiding. With tall gearing, I can be flying along at a higher rate of speed, but the engine doesn't give the impression that I'm traveling at an excessive speed.

[V8Pinto]

What are the stock intake/exhaust lobe centers? I've heard that moving the exhaust out more improves power but don't have a reference to go by.

Was it difficult changing cams with the engine in the frame?

I'm looking at the two-intake cams setup with adjustable sprockets. Looking for guidance on settings to degree that combo to.

[V8Pinto]

It's interesting that the JE piston has more beef on it - how does the weight compare to the stocker? Looks like a lower skirt and higher top, how does the pin height compare?

[Quasar]

What are the stock intake/exhaust lobe centers? I've heard that moving the exhaust out more improves power but don't have a reference to go by.

Was it difficult changing cams with the engine in the frame?

I'm looking at the two-intake cams setup with adjustable sprockets. Looking for guidance on settings to degree that combo to.

OEM lobe centers vary quite a bit as per posts by many individuals. I can't say what my OEM lobe centers were, as the 1st recall CCT spring broke just a few thousand miles after its install and caused my cam chain to jump resulting in collision of the OEM pistons and intake valves. I rebuilt the engine and installed the performance parts and made certain I used the latest oil ratchet mechanism CCT.

I like the 105/107 lobe centers that I degreed my Web cams. 104 intake, 106 exhaust has been very successful and Web suggests starting out with 106 intake, 108 exhaust, so I decided to compromise between the two by using 105 intake, 107 exhaust, as I lean towards a stronger engine in its low and mid range since I use those the most. I have no regrets.

My JE pistons are just slightly heavier than the OEM pistons, but that's of no concern to me especially since I mostly make use of the low-end to mid range of my engine. As I recall, the Wiseco 81mm 13:1 pistons were exactly the same weight as the OEM pistons. The Wiseco 13:1 pistons were actually my first choice, but there was so much talk about difficult engine cranking with compression that high when the engine is hot, that I decided to compromise and go with the 12.3:1 JE pistons. I wish I had gone with the Wiseco 13:1 pistons for the extra HP and torque that the extra compression would provide, but it truly would have made hot engine cranking even more difficult and likely would have required an additional battery either in parallel or in series for 24 volt cranking.

Even so, my engine compared to when it was stock is way better and far more enjoyable. 35,000 miles later and those performance parts still put a shit eatin' grin on my ugly mug every time I ride it.