Ducman

I believe C-12 is 112 octane. C-12 is good stuff but pricy, and I doubt you shee will know the difference between the 110 and c-12.

(Click Here) This link will give you the cc for various strokes and piston sizes. Parts list needed: 4mm stroker crank $450 Stroker specific cylinder porting/ case match porting $300-600 stroker plate or custom stroker domes $20 or $70 wiseco 795 series piston kit $180 Cool heal if you dont already have it $200 Adjustable timing plate $40 Optional, but you'll want it 34mm Carbs/cable/twist throttle $400 Intake manifold $170 V-force reeds $200 Uni or K$N Pod filters $30 ot $70 Lighten flywheel $60 Adjustable timing plate $40 Its around $1200 bare minimum for parts and porting if you do the tear down and reassenbly work yourself. Figure a couple of monthes for build time because the shit you order and work sent out to be done definitly doesn't happen over night and there is always some type of hang-up waiting for something. I sent mine off to a shop and got it built for $1450 including shipping but it probably isn't making quite the HP of some other 4mm strokers in the HQ, but still kicks ass and was worth it. I was out well over $2K when it was all said and done with the other parts added, carbs, reeds, ect. Kicking ass on every YFZ 450 I raced up the drag hill at sand mountain - PRICELESS I'm happy with my current 4mm setup, but looking back on the whole ordeal and amount of $ spent, I wonder what my motor would be like if I would have just got the best port job money could buy, carbs, reeds, ect. and just have had my stock crank welded. Also you can sell your stock crank, carbs, reed cages, airbox, ect. for a couple $'s to help offset the cost a bit. I think I got over $450 for these items on e-bay.

Yes, thats a good description of the sound I was talking about too.

I run #280's with the slots in the lid, almost like having the lid off.

Stock jetting is almost always a #200 main which will get fairly lean at 50 deg F. I'm going to say that at -10 you should be about #230.

I would start at #340 mains cause the pods can flow some air, also, typically dune ports = top end ports are not very mild.

Your kind of in the experimental range hacking off your silencers as far as jetting. It wouldn't hurt to go up a couple sizes, go up about 3 sizes if you remove the air box lid. Dont remove the airbox lid while using the stock filter, the airbox lid holds the filter in place. Some people have screwed it to the front of the airbox so they could run lid off with the stock filter. I would recommend running an aftermarket filter and adapter plate in the stock airbox to run with the lid off.

WOT 6th gear plug checks are only for verifying the main jets ( last post sounded like you were thinking of checking the pilots that way). Anyway, if it idles better when you screw the airscrews out (leaning idle mixture out) and you get beyond 2.5 turns out then you may want to go down 1 size on the pilots. Also it sounds to me like you may want so make sure that the carb slides are in sync. If they are out of sync the cylinders will want to idle differently, one weaker than the other. To sync the carbs you look into the intake sides of the carb (air filters off) and adjust the idle so that both carb slides are at the same height at idle postion (closed throttle). Next slowly take the slack out of the throttle cable and verify that both slides begin moving at the same time. If one comes up before the other then use the nuts on the carb tops to take the slack out of the cable on the side that the slide comes up late untill both slides begin to move at the same time. You can also check by holding the trottle open so the bottom of the slide is flush with the inside top of the carb and feeleing with your finger if both slides are even with the top of the carb. On my shee if the carbs aren't perfectly sync'ed you can hear the cylinders fire diferently on deceleration, start up, and cruising at part throttle. When you can't hear a difference in the 2 cylinders, your sync'ed.

If you are going to do a litle DIY port work, get the race logic porting template and do the whole enchilada. A lot of people in the HQ have had some good results with it. Do a search imputing "Race Logic" and you will find some good DIY porting info.

If you are jeted perfectly now, when you take the lid off, go up 2 main sizes and it will basically run the same as it is now with a little better performance. It isn't a huge change at all, but definitly enough to need to rejet the mains and noticeable seat of the pants performance boost. You may also need to adjust the airscrews in about 1/2 turn or so to richen the idle back up a hair so it starts and idles the same as before.

You probably wont pull 6th very well but may pull 5th faster than you pulled 6th with the 14 tooth anyway. I have seen gearing tricks for particular situations that work better using smaller or larger countershaft sprockets. I think the best all around gearing is stock or a 15 tooth front. One thing to consider, something I learned on the dyno, is that you will get your best HP output in a specific gear. My banshee dynos about 4 hp higher in 4th than any other gear and 6th gear was about 10 HP down from 4th, and this wont change by putting a smaller or larger countershaft sproket. On a stock shee the best output is probably 3rd, maybe 4th so you should try to gear it so that 3rd or 4th is in the speed range that you want your best power. Some guys that race say 100 yards or a hill climb with a highly modded motor with the best power output in 5th gear might use a 12 or 13 tooth front and start in 3rd gear so they are getting the best power output using 3rd 4th and 5th gears in the race. If you are MX racing then being taller geared might be beter so you are not shifting as often using mostly gears 1-3, and lets say you are hitting the top of 4th gear in a straight away so you are maximizing acceleration in that area of the track as well. Climbing the drag hill at sand mountain I can rev out in 4th gear but cant pull a strong 5th so 4th would actually go faster than 5th. If I had a 15 tooth vs 14 then I could still pull a strong 4th and be a couple mph faster. But in a 100 yd race in the sand I want a 14 or even 13 so I am reving out in 4th gear just before I cross the finish.

A lot of banshees make a knocking rattle noise from the clutch at idle and then it seems to dissapear when moving. When it first starts making the noise it scares you because the noise is at the same frequency as the crank rotation and exhaust rythem. My Ducati has a dry clutch with a vented clutch cover which makes a similar noise that goes away when moving. I think it is from a worn clutch basket and/or disks. I'm not saying that this is for sure your noise source, so be cautious, but I have heard similar stories and this conslusion before. Mine started doing it not too long after building the motor to a 4mm stroker. I think it is also common to get this noise when you get porting or mods that raise the HP output a hole shit load.

Choke tube fell off? Massive air leak? Did you look into the intake to verify that both carb slides are actually comming down?

Run the same plugs. I might suggest going up 3 sizes depending where your at now for removing the lid and timing advance. V-force are nice but they aren't going to add a huge amount of power, mostly make the power and throttle responce snappier and more responsive. If it runs good now (starts, idle, throttle response is good) on your pilots you should be able to keep the same pilots and just adjust the air screws a little if needed, may need to turn the screws in 1/2 or 1 turn to richen the idle back up, might lean it out a hair when you take the lid off. Adjust needle to what setting feels the best. As far as highly modded z-400s, you have to sink a fortune in them to get 45 hp. Figure the stock banshee starts with 36hp and the stock Z-400 is about 30. If you port your banshee you should be able to easily hit 50 hp, I think it would be tough to get much over 45-47 on stock ports.

Start with # 340 mains, # 30 pilots (cause Banchetta would probably even run 25 pilots on a Chevy 454 J/K) air screws 1.5 turns out, needle on the middle or 4th clip from the blunt end, that is about where you should end up anyway and should be most likely rich enough to be safe at 340 but probably pretty close, not so rich that it wont run strong orl bog at WOT. Don't try to diagnose the jetting untill the motor is good and broke in because it will seem to run rich and bog more at first especially on the needle. Do a couple of heat cycles before riding it. Then do a couple of easy 15 min rides with a good 1 hr cool down. At the end of the first tank do some spirited riding to get it good and hot and clear out the excess oil from the case and cylinders. Install new plugs, ride it for 20 minutes to get some color on the new plugs. Now you are ready to start making jeting changes. Your motor will change a lot in the first couple hrs of break in, it will seam rich at first and then start to come in when the rings are set and the excess oil is cleared out.

Did you try setting the air screws to 2.5 turns out to lean the pilots out, I would think with K&N pods you might flow enough air to use 27.5's and stock pipes. Put the needle back to the middle clip, thats probably what is making the slight bog your feeling. When I went from stock to boysen reeds on my stock motor with FMF's it ran best with the needle in the middle clip before and after adding the reeds. I think some reeds might like a change in the needle, some don't.

I'm pretty sure that is for the Lt and Rt pipe, expansion chambers only - does not include silencers.

Your symtoms sound lean, but I can't see needing mains larger than 340 for your setup unless you have port work or something we don't know. I have had a bad plug act almost like a lean condition pop or misfire on the top end but you said you already changed the plugs. Is the plug boots making a good conection with the plug electrode? How long does it take to get color on the porcelin (SP?) part of your plug. My shees dialed perfectly, backed up by the dyno sniffer, and it takes 20 minutes of hard riding to make the porcelin turn light tan and it doesn't get much more than a medium brown after hours and hours of riding. However when I do a WOT plug chop with a new plug it makes the 2mm dark band at the top of the porcelin. I have seen slightly too rich and slightly too lean to get a perfect 2mm ring. Do a WOT plug check with new plugs, cut out a section of the threads, and look for the 2mm band. If its real dark and more than 2mm your too rich, if its not quite 2mm then lean. It's accurate, i.e. if its 1.5mm then your lean, 2.5mm then your rich. I like this method. It gives you something you can measure and takes the guess work out of looking at shades of brown. Pluss I'm slightly color blind. I think the color on the porcelin throws a lot of people off. Or do a WOT check with old plugs and look at the color on the strap and the bottom ring (flat metal edge) of the plug.

I would definitly not put it past a shop, even a good one to F-up the jetting on a banshee unless they have a person in the shop that knows what they are doing. A service manager/ mechanic for a local shop once told me that he has never, and would never put main jets larger than 290 in a highly modded stock stroke banshee. Thats why I told him that I he would never be working on my banshee. They will often say "dont listen to any jetting advice on the internet." Most of the advice I hear on the HQ is way more accurate than what a lot of dealers will give, except for about 1 salesman that I have met at the stealership that actually owns, rides and wrenches on his banshee. Give the complete list of mods and air box settup and we can recommend jeting close enough so we can get you dialed in or at worst it will at least run good and safe. Ask the shop what was the old jetting, what changes were made, whats the curent settings. You might just check it over, spray some w-D 40 in the spark plug boots, look for a mistake, because it sounds like something has been put back together wrong, not like the jetting is just simply off.

I think that a set of Rockets might be pretty awsome for and all around motor with portwork that is intended for good botom end power. Of coarse the bottom would be beter with something like fatties but the mid to top would be way better with the Rockets and still with decent bottom. Rockets are going to have a bit of lag on any motor but the power comes on smoother than Toomys, at least typically.

You will gain a litle bottom end and loose a lot of top end.

There are always good deals on E-bay for mass produced pipes like FMF or PC. Check first in the for sale section. Don't be afraid to buy a slightly used set with some blueing on the head pipe part of the expansion chamber. You'll get a better price on a used set. FMF's nickel coating turns blue real fast, not like good show chrome. I can't believe my rockets haven't even turned the slightest shade of blue anywhere yet (some small chrome chips on the weld though ) Not many good deals on CPI and harder to find pipes.

I wouldn't install the reed spacers, they will make the carbs a litle closer to the air box and make it harder to remove your carbs. They may also add some lag to throttle response. I would only use the spacers when needed for larger carbs to clear the clutch arm or if you want to try them for shits and giggles while trying to dyno-tune every last ounce of HP out of your bike. They are hit and miss weither they help or hurt performance varying between different motor setups. They typically only smooth out power delivery by lengthening the intake to help sync pressure waves in the intake and exhaust earlier and help reduce the dead spot at 5-6k rpm. Somewhat similar effect with the boost bottle. Both may or may not improve performance a slight bit, but will both be in the way to work on your quad.

Any added stroke more than +4mm and you have to have the stock cases trenched so they crank wont come in contact with the case. This adds a decent amout of $ to build a stroker motor. If you have to trench the cases, might as well go with a +7mm crank. Also you'll find the best deals (around $450) on the wiseco +4mm stroke +5mm long rod crank. Thats why most people run the +4mm crank. The only place I have seen a +5mm stroke crank in on banshee superstore.com. Theres a lot of other expenses that go with a 4mm strolker, ie stroker specific porting, domes, ect. Theres a decent amount of stroker info on past threads in the HQ.

If you want top end HP to run with the decent banshees up the drag hill at Sand Mtn then you need to get some port work. I had pipes (FMF), head (20cc domes), airbox lid off and I got smoked bad going up the drag hill, I also weigh 250 which doesn't help. I got smoked by stock YFZ's. Now with my built motor I don't get beat by YFZ's and very few ported stock stroke banshees. For the trails your going to like the head, timing and flywheel a lot though.