Hi. I am not sure if my advice will be helpfull, but this what I found on the web (actualy long time ago and posted before here). here is link to very valueble info some guys from Germany collected http://www.control-line-team.de/moto.../index_en.html. If you will be able to figure out in the gfaph then you will know what to do. Just keep in mind, those graphs are for engines with no tuned pipes. With tuned pipes we have ability to make extra charge while wave comming out from cilinder it creates etra vacuum and it helps to make extra induction. So if keep this in mind then you will know that up to sirtain limit you can open induction on closing side further. But be very carefull it helps when pipe kicks in, untill that moment it will work against you-it will not be build up enough vacuum in the crankcase.
Man, it is friking disaster these 2 strock engines. I sugest you drop everything, go to the web, look for any articles about 2 strock engines, regardless if it is for snowmobile, go kart, motorcycle etc. Read everything and try to understand and I ma pretty sure if you want to know you will within 2-3 month. Go to boating and air modeling web sites-those guys put a lot of info on the web. There is actualy whole history of evolution nitro engines with all explanations and details. Just keep reading and understanding.
Good luck.

Get the weight of piston, conrod, wrist pin, G-clips take about 51% (make bobe out of heavy materila lead or something) attached to cranck and follow the rest from Nitrodude balancing procedure and if you will be able to go as close as possible-then you will be right on the money.

edwardn, i will look all this up thanks so much, i'm also looking to find how they balance the cranks after modding, nitrodude gave a way at first i didn't understand i think i may have it know. be cool :sneaky:

In my understanding rifling will work against flow (fuel rushing to the crancase by vacum creating by upward movement of piston-NOTHING ELSE, moving inside case by pressure created by downward movement of piston and negative vawe from tuned pipe-nothing else), so any restriction on the way of fuel will work against flow. I have never hird anybody try to do that. It doesn't mean that channel needs to be polished as mirror, just smoth finish will be enough. Polishing will not give you any advantage don't waist your time and money

is work to the crank done with a dremel or am i looking at some very expensive machinery here

Dremel is enough if you want to make engines for yourself or for friends (small quantities). Use diamond bits-they work just great. You can get them practicly in any hardware store. You can get made in Chine cheaper, but they don't last, Dremmel original last way more, but costs is higher. If you ar eplaning to get to moding seriously, then you will need to invest $$$$ to right machines. Not neccessarely CNC, may be conventional but will be high precision grade and pretty expencive.

can you help me understand timing on these motors we use for racing,port timming and crank timming, what modding the intake channel on the crank does and making the side ports bigger and the boost port. i also see guys reducing the thickness of the bottom of the sleeve and rounding of the bottom of the sleeve, this must inprove flow of gas and air charge to the cylender yes.

LOL My bad, I meant the Piston.

I remember now. Another way to do it without the razors. Just get an old crankcase that goes with the crankshaft, and you can use that too. If you go the crankcase way, make sure the theres no oil or grease on the bearings, make sure they're dry.

By the way, i didnt give anything away, I got all that info from EdwardN, there was an old tread where that was discussed, and more. :sneaky:

Ed, YGPM

nitrodude,edwardn you guys are top notch thanks so much look forward to talkin more

AND MORE :sneaky:

Thanks, but really, Edward is the one that told me how to do it, he deserves all the credit.

you cant fully balance a single cylinder engine. Just a FYI

Thanks guys, this info is great. Looking forward to anymore you might have to share.

Yeah, one cannot fully balance these engines, but isn't the trick trying to get it as close as possible to reduce vibrations and increase efficiency?

So we would need some kind of setup (I'm liking the crankcase method) to help us see/measure the amount of balance in the crankshaft, especially since one of it's main functions is to act as a counterweight/counter balance for the conrod & piston.

If I said anything wrong will someone please correct me.

nitrodude, do you have a pic of this method?

nope, im sorry

surprisingly most of the engines the factory guys use are not modded. they are all hand matched at the factory. i guess this would mean matching the piston and rod to the crank and also the piston to the sleve.
you would be surprised to see how much extra power you can get :sneaky:
although not everyone is a factory driver :sweat:

warmac....... of coarse he doesn't lol ;)

ya.. what the hell you would be suprised how many companies SAY they do that anyway. i bet if i went to novarossi and so did...i don't know josh cyral and both got motors, mine on monday and his on tuesday from the time i pick mine up when i leave the door they are bustin but to make the very best motor for him, not to say novarossi does this because they are bad ass, but i'm sure those pro guys have something done. i bet more do than not. war mac i'm going to build a balencer and i will post it when i'm done. maybe someone can tell me if i did it right, after i spend 20 hours on it lol :sneaky:

it's more so the piston to the sleeve :sneaky:

I repeated this until I get hasted of saying it... now, simply I promised to myself to not repeat this phrase. The unique advice I say is to not leave any engine on the hands of someone he's capable of balancing a 1 cilinder engine. because is impossible.

I can sugest you take one of old crancase which you are not going to use, cut it I showed on attached pic, then install new bearings, make sure you don't lubricate them while you balance your work ( then for storage better to lubricate), now you can do your balancing work easier.

Alfonso, it is impossible to do perfect balancing, but it is possible to come pretty close, specialy when we know our usefull range of RPM (when motor is loaded) is pretty narow-between 26K RPM and 42 K RPM. Yes there is very good balancing numbers which make big difference. Just look any of performace 21 engines-they have tungsten inserts on counter weight-this is done to improve balancing. There are many different ways to improve balancing just need to get hands on it.

thanks dude, cool to see that

EdwardN: nice idea, limited machining, good precision.


mugenb46: I guess we are one step closer now.

when you balance these motors for an RPM its balanced.....for that RPM. So if you balance it at 38,000 RPM then it will only be in blance there and out of balance everywhere else, you cant balance these motors for a RPM Spectrum. Its a set RPM area as in 1-2K RPM, not 20K. You absolutely can not balance these engines any further than that. Ive seen modders engines vibrate worse on a dyno than stock....and they claimed to fully balance the crankshaft, ive also seen other modders engines act like stock, no one is balancing them, they may put it on a machine that spins it and say the balance it, but its a big BS fest as far as that goes. Trying to balance these engines is a waste of time and money as you cant do it.

that makes all the sence in the world to me, dammit i'm pissed thats it i quit lol. but how does it get out of balence from one rpm to another, or is it a harmonic balence, that i know some shit about. when you run 30,000 dollar motors in cup and arca cars they have a range were they perform in the perfect balence around 9000 to 9800 rpm this is short track rpm 6500 to 7500 rpm talledaga or daytona the motor is not in it's harmonic balence range. because of the gear they make us pull :sneaky:

yes im pretty sure its harmonic balancing done at the factory, EB Mods claims to balance his this way but its a flat out lie.

I am not going to argue with you. You might be right-I don't know on what info you base. I know what we are doing and how we are checking if it is pretty much balanced. On RC cars you can't really feel it-you are far away from thr car and it is moving fast, so there is no way to check it, but I will get back to where I came from, when you fly control line airplane and engine is not balanced then you feel itching on the control line handle. If somebody fly control line airplanes they will know what I am talking about. So we do make design, try it on airplanes, on different range of RPM (Please don't ask how we mesure it-we have way up to 10 RPM accuracy), Then change design and fly again, and agian and again, after couple of tens samles collected, just make analizes and it is pretty much fit to certain system, which just use common sence can be converted to formula.. Then, just one more time control test and it is ready to go. This is the way how we came to the cut on the pic. Sorry for quality of pic, but this the best I could do.
I am leaiving this up to you to make judjemnt-if we are doing balancing right or no-you can call it BS, or whatever, it is not really bothering me. I know what we are doing and I know phisical results. Balancing can be done very good and averaged to very wide RPM range. We fly on from 25 K to 42 K and it makes a lot of difference compare to regularly static balanced. We tryed all kind of engines, with all kind of modding. No how much difference it is on performance-this is triky question_ i will leav it up to you to decide. :rolleyes: :rolleyes: :rolleyes: If you want to know more obout this talk to Matkemiers brothers-they are really know balancing and they are the mentors on balancing for a lot of engine designers.

Who are you? someone from Axial? All of my information was from Brian Kenny @ Nitrodyne Systems AKA mxwrench on here.

I am just the guy, who is messing with nitro engines since 1976. Learn here, there, you know how it is happened. I know Brian Kinney very well-he is one of my best friends.
And brian info is absolutly correct we did discause with him this many times, but the difference is that our aplication is slightly different to what you try to bring as sample-motorcycle, so it is different leverages on cranck, diffrent RPM, different ratio HP/capacity etc. In motorsport they develope a lot of really good thing, actauly most o it, but all of them just simply can't be transfered to niro engines.So if any time something is taking from motrsport-there is defenetly need corection to fit our needs in RC

LOL, he is the Designer of Axial engine..

BTW, how u going Ed? drop me a PM or Email if you have time

Tommy

figures, i dunno why he couldnt say that tho.

He should'nt have too... :tire:

RC_Alan

ED ygPM :sneaky:

why shouldnt he?

does ED have any motors running at the truck nat's

its nice to hear that people that really works on glow engine gives us information about glow engines.

Edvard has helped me many times when i have asked him and he is very very good at what he is doing.

He does not wan`t to brag of what he is doing and there should be of no difference to you what he does or don`t do. There are a lot of guys out there that know consideral amount of theese engines and they do not come here and talk abaout it bacause thay are alway questioned of what they know.