4stroker

while the pro-design and noss head shells might be the same, the actual domes are not, and this is where any difference in power and reliability is made. from my experience noss domes have a far superior combustion chamber design. they have been designed in 2 stroke simulation software, specifically for the banshee, and have the proper squish depth, width and angle to achieve optimum MSV, and the bowl is a perfect hemisphere, where as on the pro design ones you can see that the bowl flattens out alot more around the spark plug. 2 of my buddies have nearly identical set up banshees, only difference was one had a PD head with 19cc domes, and the other a noss head with 19cc domes. both ran on the same pump gas, same oil:fuel ratio, and jetted fairly similar too. the PD headed bike had constant issues with over heating and detonation. he swapped the 19s for PD 20s and it cured the problem. once he found out about my mates bike with noss 19s and how reliable it was, he put noss 19s back in his PD head, and it never deto'd or blew up again.

the stock cranks are better quality than the generic aftermarket ones such as hot rods. you should get at least 3 top ends out of a crank before you have to worry about it.

if you advance the timing 3-4 degrees the engine will have more bottom and mid range power, while sacrificing a little top end. buy the timing plate and have a play with it. its not hard and you'll learn something. its only like $35 us on ebay. 112 psi sounds slightly low to me, how many hours do you think the bike has? have you had it since new? if i were you i would whack the noss head with 20cc domes on, comp test it again, and then keep an eye on the compression every couple of weeks, when it starts to go down, i would go with the first or second oversize wisecos.

i forgot about that! depending on how much you remove you might be able to get away with using a thicker washer on the spark plug to space it back up. but yeah like you said Dave its gonna be a whole nicer to start from scratch! could you make domes for this guys trinity head?

yeah leave it there for a happy compromise more timing will give better bottom end but take away from the top end.

you will benefit hugely from a bigger set of carbs what brand/type carb you choose is up to you but as long as its around 35mm, and you team them up with a new intake and vf3 reeds, you will probably gain 7-10hp. i would upgrade the carbs before you resort to an aftermarket top end, if you still want more power at least you can use the same intake/carb set up on the new top end (if its a cub) also something to think about is ignition timing.

i know nothing about the chariot heads, however; i know that the noss heads, well, the noss domes in particular, have a proper combustion chamber design that was designed by someone with decades of banshee knowledge and a cylinder head design software simulator.

haha as if you can tell by lookin at that... bud get us these measurements and we will be able to tell you what type of port job it is: distances from: top of deck to bottom of deck top of deck to roof of exhaust port top of deck to floor of exhaust port top of deck to roof of transfers top of deck to bottom of transfers also need to know your stroke, rod length and piston type.

hmmm take the other plug out when you do it. what brand is ur compression tester? isnt this bike only a couple hours old? also if you use BP98 fuel you can run 19cc noss domes if you are on top of your jetting. you having just started out in the banshee game though i would get 20cc domes and advance the timing 3-4 degrees. there are 801,025,103 posts on this subject in this forum, i just counted

at a quick glance it looks like 50 thou off them domes is gonna reduce your dome size by about 2.2cc!! unless you take some material outa the hemisphere i think itll be too high on compression.

you are making perfect sense. i went to blaster pistons in my rz motor, but i machined 33 thou off the bottom of the jugs at the same time, otherwise my transfers woulda had too much duration. (they were already ported) to do it 100% right i would send your domes to jim smart at passion and have him do them. he has all the simulation software and the years of experience to know the exact squish width, angle and height that the domes have to be to achieve the proper MSV for your setup. if however, you just want the cheapest and quickest way out, machine them 50 thou deeper and set the angle at 3 degrees relative to the piston. you also have pm. mark

ah ok, its a trinity head. when i said he can cut whatever you want, i meant on the combustion chamber side. if the trinity head wont take the generic pro-design/noss domes, im sure noss will still machine your old ones for you if you send them to him. youd have to call and ask though. http://www.nossmachine.com/ if you dont have any luck there call Jim at passion racing, he will definitely be able to sort you out. www.passionracingengines.com

like what? iron bore.. conventional pistons & bearings, large clearances... the banshee engine design is nearly 30-35 years old. if your bike is close to stock i reckon you can run whatever 2 stroke oil you want

noss should be able to cut you some brand new domes to what ever specs you want, for $65 a pair...

yeah i have bought 2 sets of pipes now off frogger he is awesome to deal with. just sell your trinity's as is and make some new flanges, anyone with a lathe should be able to do it in an hour flat!

was the big flange something trinity offered or did you mod the pipes yourself? thanks, mark

hey mate are you on ozatv.com at all? get a noss head with 20cc domes, and a cheap timing plate and set it at +4. rejet to suit and use BP 98 fuel. with your pipes this will put you at about 42-45hp. if you want another 4-5hp, add vf3s and bigger carbs. if you still want more power, get a stroker crank, pistons, a port job and new domes. how much horsepower you have then will depened on the port job/type of riding you do, but would be at least 60hp, and at the most probably 80hp!! oh yeah even with the first few mods you will need a heavy duty clutch. good luck, mark.

can anyone tell me how long all the studs are that bolt the barrels to the top case? i think there are like 2 or 3 different lengths? Ie the rear inner studs are longer than the others.. also what thread type are they? Thanks, mark

haha, thats so not true! they can ride em on the road there, i was in manchester and about to cross the road and nearly got run over by a piped raptor 700! scared the shit outta me!

yeah not trying to bag him or anything, just thought it was funny it looks like he was using a template from another ad and editing it, and forgot that bit!

yeah alky is slow burning so the +8 is probly what it needs. maybe it would be worth experimenting with something like +10 through the mid range down to +6 or +4 up top.

check this out, about half way down the page under "description" it says: "This is a aftermarket clutch set up that fits your Yamaha Banshee carburetors" http://cgi.ebay.com/ebaymotors/Boss-ATV-Ra...tZ1218491074510 ??

has anyone else written their own curve?

air leak

the curve in red is what i would like to try, and if it slowed the upper/mid too much (eg from 5500 onwards) i would modify it with the blue line. the curve in green is what a +4 timing plate would look like. what do yooz think? mark