Ducman

Big Blue So am I reading the dyno right, it shows your A/F was about between 11 to 13 above 7K rpm and then the next run it was between 13 and 14 and it made about 7 more HP? Did they change the jetting a lot or do you know how many jet sizes, needle clips they changed? That looks like a pretty sucessful dyno tune. Making almost 70 HP at 93 to 95 degrees, thats impressive. Could you feel the difference and did it run better afterwards. Did it seem to make a lot of color difference on your plugs from going leaner? Sorry for all the questions but I'm curious and it is all good info to know. Thanks Bro!

For all you new YFZ 450 owners, don't be a dumbass like me and jump right into jetting the YFZ carb thinking that you know what your doing since you did it already so many times on the banshee. It is way easier than the banshee. Seriously, you can change the needle, pilot, and main easily in 15 minutes, but it's not completely intuitive, at least not for me. If you haven;t pulled the air box lid off, the spark arrestor baffle out, and rejetted with the needle out of the YZ dirtbike, do it know! It is so easy, like I said, it takes 15 min on your first try if you read the directions and know the correct way to do it, and you'll shit your pants when your feel the power difference! Best of all if you order or get all the jets from the dealer individually it's only about $20 at the most. First of all, dont try to take off the carb, you just loosen the boots on both sides and rotate the carb sideways. When I went to change the pilot and main I was a dumbass and tried to unscrew the small screws than hold on the bowl, every one I tried stripped the philips screw head because they were on so damb tight. I finally figured out you can access the main and pilot by taking off the large hex nut on the bottom of the carb. Unfortunately, I didn't see the pilot (in front of main but hard to see, deeper in the hole) the first time so after finding some instructions on the net I had to go back in and do that step again for the pilot. The instructions are in the link below. The needle is also super easy to change because the slide isn't connected to the throttle cable. Just remove the cover on top of the carb and unscrew the allen scerw on top of the slide that holds in the needle, pull out the old needle and drop in the new one. Jetting for the YFZ 450 has been figured out for each particular combo of mods probably down to more of a science than the banshee, ie. with these mods (x,y,z) your jetting should be this (#xx pilot, abcd needle, and #xxx main) On my wifes YFZ 450 I got a slip-on Yoshimura pipe, airbox lid off - jetting is #45 pilot, NCVQ needle (same needle that comes stock on the YZ 450F dirt bike and in the GYTR jet kit), and #170 main (one size bigger for colder weather). Holy shit the Yosh pipe is loud when you "get it on" and it friggin rips. If my 140 lb wife gets good at riding the YFZ I might be in trouble! changing pilot and main jet Grinding the fat end of the NCVQ needle isn't typically necessary for most mods, ignore that part Replacing the Needle Propper Jetting according to mods Main Page - The DADDOG DOGRIDERS YAMAHA YFZ-450 FREE INFORMATION PAGE.

That's good shit! I started getting pissed off cause some of those signs of the bitch cheating sparked off an old nerve or synapse in my brain from the past that i thought had gone perminantly dormant.

Yeah, I definitly have a complicated review comming up. I really think the dyno will help alot to figure out the jetting if there is a mechanic at the shop that is a good tuner and knows what to look for as far as air fuel mixtures. I have done so many changes all at once that it was very hard to even know where to start with the new carbs. It is also sending me some mixed signals as far as plug color. After it was first broke in I threw in a set of new plugs, went out and rode it for 10-15 minutes, did a WOT plug check and it was pretty black. I did this again a couple days ago and it came out pretty light colored. I know the needle was rich because it bogged real bad so I dropped the needles all the way down and it improved a lot but still seemed a bit sluggish going into the band with a slow throtle roll on and reacted better just going straight WOT. I think the case was getting loaded up with oil from break-in heat cycles at an idle and slow put put riding and now after doing a buch of agressive riding at WOT the system had dried up alot and stabilized. The silencers were wet and oily and now they are getting pretty drying and looking normal. This motor seems to have needed a bit of time to "come in" to a stable operating range. It is running a lot better know at the same carb settings than it was originally. I think when I put the pod filters on this weekend it will lean out the needle enough, and if not I will install the leaner dump tubes (needle jets) that I ordered. I will also go up 2 sizes on the main. With any luck at the dyno it wont need any major jeting changes and might be able to get it spot on with only one minor change. I still would like to know what air fuel ratios to look for on the banshee, pilot, needle, and mains at WOT. For example on a supercharged car you want A/F = 14.0 :1 under normal driving which is a perfectly balanced (stoichiometric SP?) fuel air mix for optimum combustion but under WOT you need more like a maximum of 11.5 : 1 so it is rich enough to supress detonation and a minimum of 10:1 or else you are loosing a lot of HP due to a too rich of a tune. Anybody know? Banchetta?

Here Here Long live the HQ!

The piped TRX's were getting spanked really bad up the drag hill at Sand Mountain. I could give them a 150ft head start and pass them like they were standing still, and be to the top of the hill when they were about 2/3rds of the way up. I never saw one even come close to any stock YFZ. Now a piped YFZ could give me a decent run for the money at least off the line and it would take me a while to real them back in. IMO you cant make the Honda as fast as the stock YFZ with the $1500 you saved. Spend $300 more on the YFZ for a pipe and the TRX will never even come close to the YFZ performance. For just playing around it is probably a nice quad but for anything serious it lacks the motor.

I'm getting some more parts in this week to try to get the jettng dialed in on my new stroker w/ 34mm carb setup. I called a local dealer that has a dyno with a sniffer and asked how much it would be to do a dyno run and they said that the standard dyno map was $75, they said that if I wanted jetting done it would be 1/2 hour of labor which would put it at approx. $120. My reaction was: damb that sounds like a sweet deal! They said they have the necessary parts in stock for jetting the Mikuni TM 34mm too. At first I was planning to do all the labor myself and just use the dyno as a check but for 1/2 hour of labor, I might just get lazy and say do it. Also I have decided to go with K&N clamp ons since taking the carbs off is such a bitch now that I have like 1/2" between the carbs and the stock air box and the carb intake bell is as big as the airbox opening. This may throw off all the jetting work I have done to date anyway. I think the stock air box and foam filter may be holding up a lot of performance. My main question is what air fuel ratio's at which RPMs and throttle postions should I be looking for? I haven't had any experience with this shops service department but their parts dept. always pisses me off so I don't go through them and I have good experience dealing with my local Yamaha shop anyway. Any other dyno advice, things to look for and make sure the shop is doing corectly would be apprediated as I am a dyno virgin.

Your jeting is good, your problem must be a mistake somewhere in the reassembly of the carbs or something that is incorrectly functioning with the carbs. You wont notice much difference going from a 290 to a 280 main. I doubt it would actually bog really bad like you mentioned untill you went up to a 340 main and raised the needle all the way up with your set up. I would start trouble shooting rather than tuning.

If you have pipes and mods you may need to go up a size or 2 on the main jets to compensate for cold air temps which can cause your motor to run lean. On a all stock bike it may not be as noticeable or as necessary but still should be considered.

The only bad thing I can think of is if you garage caught on fire, and the drum helps torch the garage or the rest of the house your home owners insureance would probably not want to cover the damage, but I don't think it is much worse than having 10 gallons of fuel in plastic race jugs in the garage like most of us do.

I have a 4mm dune port stroker that I've recently broke in and I'm working on the process of getting the jetting dialed in. I'm running the Mikuni TM 34mm Flat slides, stock airbox lid off/ foam filter. I started with #35 pilots (air screws 2.5 turns out) needle middle clip and 280 mains. The carbs came with #50 pilot and #280 mains. The needle that comes on the TMs seems to be way to rich. I droped it to its lowest setting and it helped a lot. It was bogging prety bad on the needle in the middle clip position and now its runs decent, just seems kind of week and when you go to wide open throttle it hits the band real light switchy. The plugs are also dark black and oily. The mains seem like they are not too far off, maybe a little rich, same with the pilots. I am geting a 2 steps leaner needle jet (orifice that the neelde goes into) to lean out the needle alot more. This is what moto carerra told me to do first before messing with the needle taper, length and leaner/richer needles. I would recommend to start with a 30 or 32.5 pilot, needle middle clip, or if you got a new set of the TM 34mms like I have go straight to 1 or 2 steps leaner on the needle jet orifice, and run the 270 main that it came with. That should get you close to where you need to be and it'll run half decent.

I have both and I think the Banshee is a lot faster and more exciting in the sand when ported and stroked. I didn't have one YFZ 450 that I couldn't beat racing up thunder hill at sand mountain last weekend, although they did often get the jump on me off the line. The 450 has some pretty nice qualities and kick ass as well, jumping, wheelies ect. the 450 is better than the Banshee. But I would choose the Banshee in the end. I say get both or keep the Banshee.

Some more pics taken with the digital camera from the day before when it was clear.

Here are some pics of Sand Mountain from our trip. Most of the pics are pretty dark because of smoke from wild fires in CA made it almost like an overcast cloudy day. One pic is of my new ride and the snow that almost caused it to go of the road! I'll post a couple more tonight of the drag hill taken on the day before when it was clear. Looking south along the ridge from the North end Looking up a hill on the North end Looking down that hill on the North end 2 wheeler jumping about a 60ft gap My wife and me on her YFZ Me and shee Sand mountain in the distance from the North East looking South West Snow that almost ended the Lightning

Which Boysen reeds are you talking about. My experience with the boysen power reeds (ported/dual stage type) is that they didn't need any jetting changes. If you got reeds, same design as stock, that are a lot stiffer, what you may be feeling is the reed making the power feel weak or slow to respond on bottom but hard hitting and much stronger on top and that is what it is designed to do. Some reeds are designed for better top end response, some for bottom, or all around. Thats just a guess, I would try some different needle positions to see if jeting could smooth the power delivery out.

I would use stroker domes before using the spacer plate on top of the cylinders. Way more reliable and simple. Of coarse I am not a performance shop but I believe that is the way almost all of them do it.

I think both bikes will be evenly matched in every department except the Yamaha motor is more powerful.

Screw the whole playing games B.S. When I was first living with my wife (girlfriend at the time) she tried the whole mind controll shit on me and when it didn't work she'd act like we were over and she was moving out. I'd say fine, get the F*** out and ignor her. It was always a bluff and she never actually made it out of the door for more than 5 minutes. I never actually wanted her to go but had to put my foot down. She grew out of that phase and learned to let go of the reins and give me my space and freedom and is a really fun, cool and understanding woman now. My case was a bit different because we both were confident that the other wasn't and wouldn't cheat, but seriously if my wife would have kept acting like a friggin prison warden and pulling B.S. mind games, I would have locked the door behind her one day. The girl friend before my wife got kicked to the curb for playing the same shit your girl is and later on I found out she was bangin other dudes even before I suspected it.

Typically if your carbs aren't overflowing/leaking or running out of fuel/ running the bowls dry or just not letting any fuel in, then dont touch the float adjustment. On the carb syncing, hook up the throttle cable, take off the air cleaner and look into the intake to see if the slides appear to be the same height at idle (zero throttle), if not adjust idle so they are the same, then start it and adjust both idle screws evenly to get the desired idle RPM. Also the slides need to begin to move together at the same exact time when you begin pressing/twisting the throttle. Usually when your cable adjustment is out of sink you can hear the slides make 2 clunking noises when they close instead of one. Use the cable adjustment at the top of the carb to take the slack out of the cable on the carb slide that comes up late. Typically on my stock carbs with TORS I never had to sync the carbs in slide idle height or cable pull even after taking the carb tops and slides off many times. They went back together the same as they came off, in sync. But, if you just put a new cable on then you will need to sync the carbs.

I got a complete stock set for sale, pretty inexpensive, bored to 28mm if buying or fixing slides is too expensive or doesn't work out.

I liked the rockets on my stock port motor. Unbeleavable top end difference over FMF's and only slight loss on the bottom end. On my 4mm stroker I've still got a way to rich needle and slightly rich main with TM 34mm carbs to get a good feel for the mid range. It doesn't really bog now that I droped the needle (that came stock on the carbs made for something like a RM 250) to the leanest setting but not as peppy as it should be kinda causing a somewhat more light switchy power delivery. It also could be somewhat due to porting also, I've only had her running for a little over 2 weeks now so I've only have time to due minimal tuning after break in. The mid/bottom end was good when stock and I think it will be better with some more tuning, but it frigging rips on the top end. There were no piped YFZ 450s that could hang with me on the top end up thunder hill at Sand Mountain this weekend and only a couple of ported banshee's and I was running really friggin rich due to going up 3500 ft in elevation from sea level with no jetting change and running rich to begin with. I'd say that I'm pretty satisfied. I like CPI's silencers fit and finish better though.

With the Air box lid on, stock or foam filter, stock cylenders, FMF fatties , sea level, approx. 80 deg temp, with no other mods effecting air flow use a #27.5 or #30 pilot approx 2 turns out on the air screws, needle middle clip and #260 mains. Air box lid off use #280 mains. Main size will increase with other mods like K&N filter, timing advance, colder temps, porting ect. Try to error slightly on the rich side to be safe.

2nd the SST's

Parts are still for sale. I'm leaving Thursday for Sand Mountain so I won't reply to questions after Thurs morning until Sunday evening.

There are some 2 strokes out there that are fairly high maintenance like the 2 wheel MX bikes that only have 1 ring on the piston and needs to be re-ringed regularly, but the banshee pistons and cylenders will last for years as long as you don't do stupid things like adding mods that require jetting changes and don't rejet it. When I was from age 16 to 18, I had a Husqvarna 510 mx bike, 4 stroke, that sucked a valve and destroyed the head and piston. It was going to be over $1000 in parts to fix it so I ended up practically giving it away because I couldn't afford to fix it. A banshee will typically never cost anywhere that much to repare the motor if it does blow up and if you look at the maintenance costs below, re-building the top end on a banshee every few years might seem cheap. I just spent $185 to get the first service/tune up on my wifes 4 stroke quad, YFZ 450. I'm thinking the maintenance on it is more expensive than the banshee unless I learn how to shim some valves. My 4 stroke Ducati street bike is up for it's 12K mile tune up and thats going to cost me about $600. If you get a 4 stroke that can match the performance of a banshee then it won't be cheap or maintenance free either.