I'm getting a stock bore Venom 12.25:1 piston. Should I have the crank balanced to the new piston ??? The bike is a early 04 with lots of hours but very well maintained.I'm on the smallest valve shim & figured while I had the head off for a valve job I would install the new piston.Is there a port/polish job that works well with this piston & hotcam stage 2,stock carb? Thanks Dave.

Ride Red-

John has been busy and hasn't been able to be on here much lately, so I'll try and answer your questions for ya...

Anyways, there won't be any need to have the crank balanced for the new piston. If it's an early '04 with lots of hours though, you might consider installing new main bearings while you have it apart. Again, not necessary especially if you haven't seen any shavings in the filter, but something to think about...

Other than that, you would definately benefit from having Venom port and polish the head at the same time you do the piston. They offer a killer package price on the porting/piston combo on their website: www.venomperformance.net At that point, John could recut your valve seats. Sounds like you will need new valves also if your using the smallest shims...

Bottom line is, you would have a very respectable combo with the piston, porting, new oem valves, and the hotcams stage 2 cam, even with the stock carb. While you're in there, I would also suggest replacing the oem valvesprings if they've never been changed. Cheap insurance, and they are inexpensive from Honda.

If you then wanted more, you could consider upgrading to +1 valves. It all depends on your budget, and goes up from there!!

Hope that helps- Kris

According to the post on piston weights in the eng section the stock piston weighs 457 grams & the Venom piston weighs 377 grams.(80 grams lighter).Wouldn't that cause a balance problem???

I ran that same piston in my 05 and never had a problem or felt it needed to be balanced. You'll be fine.

80g is a big difference, if money is an issue get it balanced with a new piston and hold off on the port and polish. You will get alot more life and a little more power out of an engine that is balanced and save money in the long run.
You can't feel if a single cylinder is out of balance BTW.

JUST EPOXY 80 GRAMS OF ALUMINUM ON THE BOTTOM SIDE OF THE PISTON , TAKE THE DYE GRINDER AND TAKE AS MUCH METAL OUT OF THE HEAD AS POSSIBLE . THEN TAKE A BIG HAMMER FLATTEN OUT THEM VALVES BACK TO SPEC THAT THING WILL RIP . (LOL)
DAVEGETTHATTHINGBUILTSOICANREVITTOTHEMOON!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

try running an unbalanced 501 build for a day and tell me if you can feel if a single cylinder motor is out of balance

mixxer has stated in the past that when you have a piston that is lighter like this case it is much better than if it is heavier. the piston is what is starting and stopping several thousand times a minute. it's always better to be lighter, will be less resistance.

So if the piston is lighter I dont need to have the crank balanced????

Well I hear that nitrous is better so I'm gonna put it on and do no other mods. does this sound right???

OK so if someone were to build a 501 from parts and not balance it the effects would be obvious, unfortunately this isn't what we are discussing here.

Replacing a piston with a lighter one won't feel much different because your crank is taking the beating.

when these bikes were made the crank and piston are made as an Assembly. the heavy piston's accelerating up and down is creating forces and the crank is throwing it's weight around creating forces to counteract those made by the piston, making the engine somewhat balanced.

Now throw a lighter piston in and you reduce the forces that the piston exerts on the crankshaft (yes the lighter piston is creating less force on the crank allowing the engine to rev quicker) The crank is still throwing the same weight around but now has less weight from the piston (80g less in this case) to counter act the forces it is creating. This will not be felt by the rider, but your crank is absorbing this imbalance up to 10,000 times a minute. 80g seems small but at high speeds it creates high loads.

Everyone wants easy power, swapping a piston for a lighter on is easy power and a shortcut.

An unbalanced engine will be a liability and have less power.

You want your machine to rev quick? light piston helps, balancing the crank will make it lighter and rev quicker.

I have never heard of an engine builder who thinks you can change piston weight and not balance an engine.

Don't believe me? try reading a book. I know a good one, it's called Design of machinery: an introduction to the synthesis and analysis of mechanisms and machines , I took the class in college and know the book well. this is a pretty basic approach anyone technical can understand
heres the link to a google books preview
http://books.google.com/books?id=iepqRRbTx...ncing#PPA674,M1

everyone wonders how engines builders are so good, it's not an art it's math pure and simple. books like these will learn you on engine dynamics ( I have more references if anyone wants more).

Have an understanding of what you are talking about before you go posting what you read on the net and have no real knowledge of.

Balance your crank with a new piston and write the weight down, your next one will need to be adjusted. It will save you money and headaches in the long run as well as maximize power.

Engine balancing is grossly overlooked, many of the sob stories of engines blowing up would not be if it were for properly balanced engines.
take your eyes off the dyno charts for a min. and think about the day ruined by you motor blowing up. 60HP is no good if the engine lasts 20 hours

MIXXER where are you

x2

RIDE RED take this question to KBR I think he uses a lot of VENOM STUFF and KAM should be able to answer this for you .

porting would add power and torque across the entire powerband... if your valves have pulled in enough to use the smallest shim, you will get a boost by just getting fresh valves and seats cut..!

balancing the stock crank wouldn't be necessary.... on hot rods strokers its a good thing to do, but the stock crank wont need it...

Would I be compleetly nuts to remove a-bit of weight from my crank webs myself since we know the venom is so much lighter.
Is anyone running the 12.25-1 venom on the stock 06-up crank and for how long.
If im understanding corectly, when the piston is not the proper weight to match the crank than the extra stress should be transferd into the crank main bearings not the rod ends at all.
If this is correct??? when comparing some of the engine combos people are running on stock crank bearing sizes... I should be safe to run this piston right? If someone has some input on the best piston for the stock crank not ballanced, that would help. thanks!

You'd be nuts to say the least BEAKER. My advise would be to keep away from modifing your own crank.

Two options: Send it to a professional crank servicing company like Crankworks in AZ. or run it as is.

Im sure you would be fine to run it as is.

thanks for the input... Ill vere away from screwen with my crank. Just sounded like fun! With what ive read I think I feel fairly safe running this piston for the rest of the time I keep the stock crank. I plan on changing it on the next tear down anyway. I will just plan on a ballance when I do it.
Any suggestions on a different piston or should I stick with the venom 12.25-1 at 5000 ft elev.
thanks again.

higher elevation means less cylinder pressure from less cylinder fill in the thinner atmosphere.....

everything depends on tuning \ mods \ available gas...etc...etc...

bust some people run premium pump gas with 14.25:1 compression ratios with high altitudes... the cylinder pressures would be comparable to a pump gas setup running at sea level ...

So would I be o/k getting the higher comp piston at my elev. I was thinking about touching up the head squish slightly. I am just guessing here but the slight gain in squish, and the slight loss in comp from elev should compensate for the 14-1 piston right? Im no master builder here so Im hoping for some advice. Dont wory... I wouldnt remove much at all. I saw the pistons on sale so Im waitin till pay day to place the order. I think I got 2 friends to get em with me.what should I do? I am o/k with running 50/50 race fuel mix in winter but I cant do it when Im riding every weekend. Thanks.

that all sounds pretty correct...

the best \ least expensive way to get high octane availability is to use Kemco Oils tetraethyl lead additive with good pump gas...

our testing has proved it to be 100% reliable up to 15:1 compression

ok.....well i just ordered a 12.25:1 94mm piston for my 04, it has the hrc kit and nothing else, i'd estimate that the motor MAY have up to 200 hrs on it, but less is likely. i intend on stripping the head, possibly replacing the valves if neccesary and doing a mild cleanup of the ports myself.
My question is that of a jetting nature, I intend in having the bike dynoed after reassbly, not for bragging rights, but to proper tyning. What is a decent place to start, ie.- main, needle setting, pilot for so that i dont get charged out the wazzoo when it comes time to tune? Elevation 1150ft @ nearest airport.

by far the biggest influences on jetting are the combination of the intake and exhaust systems....

the HRC kit you have should have jetting that will be a very good place to start you tuning from... your next planned step, an A\FR equipped dyno, will be the way to get it perfect from there...

Thanks. Im pretty sure that the shop im going to hs a dyno that is A/FR equiped. he's one of two guys i know of in western new york that have a chassis dyno.

Sorry to hijack your thread Beaker. but my question really wasnt worthy of its own.

Thanks again Mixxer