what did the three slits cut by the crankpin do for you?

warmac, i'm not a newbe or a pro by any means i don't know of any mod spacific web sites, i just see pics in magazines and try them myself. when i do a motor know i will start of withe the sleeve first. motors have there own timing depending on what brand and style of motor, what i mean is you can have 2 motors different types of motors and do exactley the same mod and get different results you just do little things one at a time unless you are a pro and do everything at once and know what it will produce

german muscle, as i have said befor i am not a pro. i do these mods on theory only and what i can pick up on what other pro mod guys do. so any way those cuts help to cut through the fuel and air when it is being forced into the combustion chamber, when ever you can cut the fuel into finer particals you want this. it will burn or create a finer mor efficiant burn. a mist of fuel will burn or combust better than drops of fuel, if you can picture that.

Edwardn, thank you for that info, it's good to have someone who is willing to give ideas or facts about this stuff. i love doing this mod stuff to my motors, it intreges me to see what different things would do. i am glad i donn't know everything about modding motors, when i do it myself i learn more, learn from my mistakes. :sneaky:

Edwardn: do you know if "rifling" the crank intake has ever been tried by tuners/manufacturers? i know polishing has been done, but i've always thought that if the intake was given a proper rifling, that it could help to force air into the sleeve. just wondering. thanks.

mugenb46: thanks for the reply. I've only modded the sleeves of a few engines myself, but I've never touched the crankshaft and probably wont until I find a way to get around that 'balance issue' that's always there for crank mods.

In short, I'm not sure what I'm doing there :o ...doing more research on the timing for now.

warmac, no problem. i'm working on that my self. it's hard to find anyone that will give expierenced advice, you can change timming by port work and crank work i believe. by removing some of the top or bottom of the intake ports on the left and right sides of the sleeve, plus put the downward cut like most people do. i have also seen people make the bottom of the sleeve thinner and round of the bottom of it this will help flow. :sneaky:

warmac, also if you find any pics of a crank balencer or see what one looks like let me know. i am trying to talk a buddy into machining one out for me. then i will be stuck with trying to figure out how to actuely balance the crank with the rod and piston on the crank.

What you should do is do a search on 2-stroke engine modding... Putting pretty cuts and the like will only go so far... And keep in mind when you cut on the crank, there is a good chance of added vibration, which can lead to worn bearings and con-rods just to name a few... Unless you've seen a good Modded motor done the right way... Murnan, Motorman and Edwardn are the 3 guys I would pick there brains when it comes to true engine modding... If they are willing to share some sound info... You're lucky... What most guys do is have one of there motors modded by someone that says they know what they are doing at the local track... One of the fast guys... Then they just copy there work the best they can... When I saw the work done to the OS-Speed TZ-12, I knew I could copy the sleeve work, no problem... The crank was a different story... Most guy can cut and guess and hope for the best... The names listed above know how to figure out the hard numbers and have the right equipment/machines to do the work the right way... Shoot them a PM and see what they say... .02

RC_Alan

rc-alan
i was able to meet murnan at fernando's, ya he for sure is on top of his game on that stuff, to see his motor in his car and frank sosabee's was unreal, i can only explain them as formula 1 or F1. that is excactley what they sounded like blistering power. i have seen his work and it is flawless, very clean and you can tell there is pride and knowledge in that kind of work. i know he is a busy guy, and i know people are not always willing to give up info. i would just like to know how they balence the cranks after moding and what they use to make the cuts into the cranks. CNC machine? i used a dremel on everything and it took forever, and realy does not look as clean. crank balencer is what i'm digging for though.

What you do to balance the crank is, you weigh the sleeve/conrod assembly on a very sensitive scale. Then you take that weight and make a sleeve that fits on the crank pin. Then, you take 2 rasors, and set the crank on top of them, you remove (or add) weight until it fails to stop on the same spot everytime.

nitrodude, why do use the sleeve in that equasion, or maybe i missunderstood. thout you only weigh the conrod and piston with the crank. is there not a device that has two bearings to place the crank with the rod and piston in it like the engine is set up. I'm sorry this description is hard to picture, please explain.

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