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were turbo cranks just snake oil ? seen people do similar stuff on the head. prettty sure it amounted to a waste of time. probly reduced power actually

it may have been better you didnt get much advice from websites. there must be 100's of 2t sites and alot of the info posted is bullshit that can lead you down the wrong road. books aint a bad way to learn a few things. atleast you know the author most likely has a pretty good back ground in how the engine works. practicing on a few engines aint a bad way to learn either

if your refering to a honda, some of them the reed cage sits in so far it blocks off most of the boyesen port so im thinking its defeating the purpose of even havin them ports. ive heard of people moving the cage back alittle but i havent tried it myself. hard to say without knowing what engine you talkin about.

honda tried rotary valve on a mx bike. they must not of liked the results

hmm i wonder who some of the other shops are that didnt pay their bill

as for the longer rod and spacer making the engine lazy. im not sure when can say that so easily. we dont know what the case compression is right now. and does the pipe not have anything to say about this extra volume ? like tfaith said earlier, i think some pipe will do much better with bigger case volume. so i dont believe its a cut and dry answer to say more volume is a bad thing. my opinion of course

sstaton said he seen a engine that had alot of material removed from the crank area. i took that to meen down in the portion of the case where the crank wheels swing. i was merely stating that it doesnt make sense to me to add the extra volume in that location because of the long distance it would need to travel to reach the trans ports and cylinder. thats why i showed the photo with the green and red lines. makes more sense to me to keep the volume up higher where its travel distance to the cylinder will be much shorter. im sure you understand

i dont understand what your saying. maybe you misunderstood what i was saying. lets leave the pipe out if it because i dont think it has any relevance at this moment when the piston is heading down wouldnt you want to give as much of your case volume as possible, the shortest route possible to reach the cylinder ? this is what i was saying in the post above which has the picture this isnt a argument about whether a particular engine runs best with X amount of case volume. but rather where the volume should be located

its hard to say but some things he wrote about are alittle outdated. he said 4000 ft/min piston speed was near the absolute limit. any modern engine of good design shouldnt have a problem well above 4000

well theres several ways you could do it. im gonna test a longer rod and spacer plate hopefully soon heres my thoughts on that. when the piston goes down the mixture has no choice but to go down also. where the mixture ends up will depend on available space. it stands to reason in my mind that the mixture will go to the area that has the most open space. so if we leave the case area (between the red lines) as small as possible, wouldnt that meen more mixtre will remain higher up (between the green lines), where it has only a short distance to travel to reach the cylinder ? this is mostly why i think creating any extra volume down low in the case area between red lines) is a bad idea. just my uneducated opinion

if you were going to increase the volume it seems like it would be best to do it up high. perhaps in the tunnels themselves or near by. in 1 transfer cycle not all the case mixture will make it to the cylinder. the tunels can only pass X amount in a very brief time. so to me it doesnt make sense to put extra volume far away, like down in the case bottom, where it has basically no chance of reaching the cylinder on that particular cycle.

not KOC. just a nobody that prefers to work on my own shit

tfaith thats great your trying to help but theres a few things you should realize and probly already have. besides the site sponsors theres probly on 2 maybe 3 guys that do their own work. everyone else has likely never touched a porting tool or know what happens in the cylinder and pipe during a running cycle. zillafag for example. sprinklerman and trickcarbine are a couple more that know only what theyve read on google. your efforts might be better spent on other forums but im sure you already realized that

thats what happens when you put a engine in a cardboard box. blame the jackass that shipped it. should of used a cooler from walmart. $10 the shipping company most likely will tell you to eat crow

less talk and more action

i wouldnt automatically put blame on the machine shop. maybe they fuked up and maybe not. the problem you have on any head that doesnt use locater pins is they have alot of slop between the stud and hole in the head where the stud goes through so it lets the head move around. thats why you normally want to make sure the diameter of the head is just slightly larger than the cylinder bore. other wise you may end up with some of the head surface sticking into the bore. now if your head used locater pins like ktm and some hondas then you could machine the head diameter exactly the same as the bore and be ok because theres no movement between the two parts also before you put the cylinders on the case, hold the cylinder with the head on and look up the bore. move the head around in all directions and notice if it protrudes into the bore at any point

aircompressor doesnt have a tuned expansion chamber. atleast the ones i seen didnt. so maybe a 2t is more than a simple air compressor

you call every shop in town now your here preaching the gospel. for fuk sakes. 180 is at 100rpm when the engine isnt even running, pipe isnt workin, scavenging is barely taking place bla bla bla. what the hell does that have to do with what happens when the engine running

i seen you have a stroke crank but you dont need to drop the exh floor. i dont see any advantage to making the exh bigger at the lower portion. normally i like to leave that area small as possible. wasnt critisizing your work, just wondering what your reason for doing it was

sweet. i can understand dropping the transfer floor to bdc but why not leave the exh where it was ?

in this thread matt shear seems to suggest kickin compression doesnt really matter. go talk with him if you still have a argument ! http://www.atvdragracers.com/forum/two-stroke-technical/5876-10-mil-cub-2.html

led does alot of honda stuff and i never heard anyone complain but i never heard him talk much about other engines. i think hes been around about as long as anybody else so im sure hes seen a banshee or two

should of asked kim what he thinks of all this crankin pressure mumbo jumbo. shit he probly doesnt even own a psi gauge thats how relevant it is

this is just my opinion but i think alot of the problem is some shops have nothing more than the school of hard knocks for credentials. if more poeple had backgrounds in engineering, gas dynamics etc etc i dont think they would be scratchin their head why the pistons keep melting a hole in the top

damn you guys get all up tight about this pressure crap. soon as the engine lights up it all goes down the toilet anyways. make the engine run good when its actually running, not when kicking the bastard in the garage showin off to the fat neighbor lady