Ducman

If you have 18cc domes with 160-170 psi on stock porting at sea level, I think she may be worn out on the top end, sounds too low, should be 160 with 20cc domes. I would also say 30 pilots, airscews about 2 turns out, needle 3rd clip, 340 mains. 400 mains are way the hell to big on the stock port. I ran 310 - 320 mains with rockets on the stock airbox/ foam filter/ lid off, stock timing, sea level, stock ports and it was plenty rich.

I just heard on the radio today they are going to be playing in a small venue in Chico CA sometime in may, maybe I will get to see them.

This weekend (thurs, Fri, Sat) on the OR coast I used 17 gal of 110 @ $5/gal and a little over 3 bottles of 927 so the total was around $100 of fuel. Also $140 (16 mpg) in fuel to get to Oregon and back split between me and one other person.

Mill head .030, advace timing +4, lighten flywheel, mild/clean up port, If you go with a full dune port then get t-5's/CPI/ rockets. Pump gas will work fine. Adding compresion is mainly for low end, but if you don't need it then you won't need race fuel.

I know people put rockets in the drag pipe category, but I wouldn't consider them a top end only pipe and they definitely dont have a light switch effect when the power hits. They dont come on as strong and as early as the FMFs but they just build power all the way to the top and rev out soooo much higher. I went from FMF Gnarlies to Rockets on a stock port motor and I rode just about every type of terrain immagineable. About the only thing the FMFs did better was when you were just putting around and only using low end power. Any type of agressive riding and the rockets just simply outperformed the FMF by a huge margin. 5th and 6th gear were gutless with FMF's and pulled like a bitch with rockets. As far as the leg burnin thing, I wouldn't ride in a pair of shorts and do any wild manuvers, but unless your half falling off or going over the bars and doing everything you can to stay on, you wont get burnt. I don't think I've touched the rockets a hole lot more than the FMF's I had. Spark plug change is easy through the front, maybe a little difficult the first time or 2. If you have a pair of riding gloves on you can change the plug even when the pipes are hot like on a plug check with the wrench in the tool kit no problem.

Banshee motors are way more reliable, pistons and rings last longer, and have less problems than a modern 125 or 250 motocross bike. The banshee motor was taken from a street bike so it is made to run for a long time between rebuilds. A shee with stock ports and carbs will get pretty decent mileage if your just cruising trails and fire roads.

I would sort of sum up the different port types as what RPM the motor gets "On the pipe" and what RPM does it drop off the pipe. Dune or drag ports are going to make power at higher rpms an give the best acceleration but you have the RPM's higher to get on the pipe. Also the highest HP output. Typically from 6 to 10K. Also usually raise the exhaust port which lowers static compression a lot, so you need a lot of timing advance and pretty small domes to get compression back up for more low end torque to compensate for less low end HP, not necessary, but helps rideability. Then you need race fuel. This is not always true but somewhat typical. MX has the widest RPM range, best in midrange power, and best top end you can achieve without sacrafising too much botom. probably 4500 to 9K Gives you the most useable and widest power range in each gear. Woods, or trail port is more or less a mild port or clean up port. It cleans up casting flaws and opens up the ports a little. It will have a similar power range as stock but will flow more efficiently and make more power from bottom to top than stock. probably 3500 to 8K Gives the best traction and ability to be a gear too low or lug a bit and not make it as necessary to shift down or feather the clutch to get into the band when just rolling on the throttle.

I think its a combo of his lower gearing, Toomys, and v-force all giving a slight advantage. You could possibly be a size or 2 rich on the main wich could drop a couple ponnies and you could go to +4 or 5 on timing. PC pipes are all right, I think the Toomys would be better in a drag through, probably a slight top end advantage. Porting would help you the most. There are many builders to choose from, do some reading on the HQ to learn about the many names out there.

And what kind of airbox air filter configuration.

Its hard to mix toluene with pump fuel to get over 100 octane. You have to use more toluene than fuel at that point and I have heard many times not to mix over 50% although I dont know why. I have also figued out the cost of buying toluene and mixing with pump fuel and it is cheaper for me to buy 100 octane fuel, or at least it was. A month ago it was about $3.20/gal now it is about $3.70. Same as 110, it was $4.30, now it is $5.00. If you are using say 20cc domes and timing advance and need only about 95 octane, it is then cost effective to mix pump fuel and toluene. Here's the equation for figureing out the result of adding (X) gallons of fuel at (Y) octane and Z gallons of tolunene at 114 octane: ((Y*X)+(Z*114))/ (X+Z) For example to fill your 5 gallon race jug use 4 galons of 91 pump fuel + 1 gallon of toluene = ((91*4)+(114*1))/(4+1) = 95.6 octane From the research I've done on toluene, it is similar the additives that are used in gas now. It is a petrolium distilate just like gas (both are distilled from crude oil). They have a slight bit more enegy per unit than pump fuel so it has a slight performance benefit aside from being able to run higher compression. Toluene and xylene are both aeromatic hydrocarbons. Gas companies can use aeromatic hydrocarbons to increase a pump fuels octane rating and it is still considered pump fuel by the industry standard untill it gets over 40% aeromatic hydrocarbons, but it typically doesn't exceed 10%. Here is a post I did on toluene a while back Clicky clicky

I've had some moments on the banshee that were similar to that.

3.5 to 4 in back 4.5 to 5 in front, banshee and YFZ

You may be a tad lean, couldn't hurt to go to 320 or 330 if it is 50 deg or less. 310 might be about what you need for summer jetting. However when you are dialed in right on the money it will take a while for new plugs to put on some color. Tan is dialed, medium brown is slightly rich/ safer.

My 34mm TM Mikunis fit using the stock airbox with about 1/2" between the airbox and the carbs. I had to loosten the airbox and move it back to get enough room to get the carbs in. It was a real PITA though and I went to pods for ease of changing jets because I had to do a lot of tuning to get the carbs dialed in. I never put the stock box back on. I got K&N's for the sand and uni's for dirt. You may want to get some uni pods ($25) while your doing your tuning and put the box back on when its dialed, zip tie the coolant overflow to something in the meantime. You can get another 1/2" of space by trimming the stock airbox runners. I have some silicon carb boost for the stock box and 34mm carbs that are buggered up on one edge (had to trim a small spot off the edge to get to the air screw). You can have them for $5 shipping fee if you want to try trimming them down. The boots are a rip off new and it sucks to be carving them up for as much as they cost.

I would think for low end grunt and for the motor to come on the pipe early (power band comes on at low RPM), boost ports in the intake side as with the 12 port and an MX style port would be hard to beat. But is the extra $ for the boost ports worth it to you? I didn't vote because I could go either way.

Get pipes and some good porting that should give you the advantage. Its pretty tough to beat a piped YFZ with a piped shee. The shee has more overall HP potential, but it is hard to beat the piped YFZ with just bolt-ons. Your best bet is on a surface with good traction and the banshee will walk the yfz on the top end. YFZ top speed is much lower than the shee too, mainly due to not having a 6th gear.

The rim ofset may be different. I know the stock YFZ rims are about a +2.5 total width on a banshee. I'm not sure about the raptor. But they will fit.

You should be able to find a rim and stock throttle for cheap on e-bay, or post what you want in the wanted section on the BHQ. I am very skeptical about letting my friends that are good riders, ride my shee of YFZ , much less a girl friend of a friend. You should have got the blow job up front before shee even rode your shee. As for the steering as far off as it looks in the pic there has to be a majorly and obviously bent part somewhere.

Is that plug from a WOT plug check, 5+ seconds in 6th gear using a new plug? The 5mm band looks real light in color. Your main size sounds about right.

Your going to want about the same size main as with stock carbs.

I just want to make sure you know not to take off the air lid box with the stock filter, the lid holds the filter in. An air box adapter plate w/ filter that clamps on to the plate is a good first mod and cheap insurance. Then you can take the lid off. With all mods effecting exhaust, intake, or ignition you must rejet to maximise power and so you dont run too lean and melt stuff. I'd probably get a couple more hours on the motor and wait to take the lid off when you put on pipes. If you plan to do pipes soon, might as well not mess with the jetting only to change it again a short while later. Pipes are a huge improvement and the lid is minor. I had 20cc domes and rockets on a stock port motor and I liked it very well. If you ride sand at all then I would highly recommend Rockets, if you ride 100% technical trails them probably FMF or PTR.

Thanks extreme. I figured some company would probably make them, I just haven't ever heard about them on here or listed for sale on any site. You hear all about monster bigbore strokers in adds and such, but you dont get all the nuts and bolts info on what all parts are involved if you wanted to DIY. I know about needing to cut the domes. I have stroker domes now, I'll have to ask Noss if there would be enough room for a O-ring groove if the domes if are cut wider. It seems like there is not a lot of meat on either side of the o-ring groove now. Might have to have an o-ring on the outside edge of the dome and not in a groove. I know big bore domes are common but I think they aren't typically cut to allow the piston to go into the head like stroker domes.

At first it sounded like the choke tube was off but you said you checked that. Sounds like an air leak to me. Do you have gaskets on either side of the spacer? I personally wouldn't run a spacer unless I needed it for carb clearance (not an issue for you since you have stock carbs) or I did a before and after run on the dyno and it showed more HP or a smoother curve with the spacer. I got money on an air leak.

Like JJ said, are you doing this to correct a problem in how it is running or just want to check that the carbs are in synk? The space under the slide when it is down is so it can get enough air to idle. This is normal. You want this space to be even on both carbs. Make this space even with the idle screws. When you just start to crack the throttle and the slides begin to move, you want them to move at the same time. Make the slides move evenly by adjusting the the nut on top of the carb cap to add or remove slack from the cable on either side. The needle is not supposed to come all the way out of the dump tube, stock or aftermarket.

I'm wondering about the long rod +4mm stroke crank bigbore starts at 68mm, blaster pistons only go up to 67.5mm standad bigbore piston sizes are 68mm 68.25mm and 68.5mm Bigbore blaster pistons starts at 72mm