Adding more oil is'nt going to make it run leaner, I don't no where you got that from, it's going to take longer to burn if theres more oil, that in return will make it run rich.

2000 SCRAMBLER 400 2X4

SCRAMDADDY400

 

No, he is correct. Lean or rich refers to the air/fuel mixture. Oil is not part of the equation. Oil is only there to lubricate the engine. However, since oil takes up volume, it must be compensated for in the jetting. If you add more oil to the mixture, you effectively have less gasoline in the same volume, and a 'leaner' mixture.
Bottom line, when it is colder, and in your case, very cold, you must rejet your carbs to allow more fuel, because you get more "air" when it is cold in the same volume. Remember, carbs are rated at cfm's, cubic feet per minute. They flow volume, and different conditions have more or less air in the same volume.
It sounds like someone put some performance stuff on your machine and didn't rejet (larger mains) to compensate. Now it is bitter cold and your already lean condition is very enhanced. So you are running very lean and damaging your top end. Plus you have wiseco pistons which are prone to cold siezure if you don't warm up your machine properly. Most Banshee's take 3 to 5 minutes to get up to operating temp, more if it is cold like where you are at. Since you are running lean, your engine is operating very hot.
Buy a manual, do a plug check, and go from there. Find somebody to ride with who has some knowledge and can help you with this.
Also, dragging a machine around to start it is not good for the gearbox. You are applying power in the wrong direction and eventually you could break something.

 

My '99 Banshee ran for two years, summer and winter (without rejetting) with the following specs: FMF fattys/PC2 silencers,Boyesen reeds/spacers,boost bottle,K&N filter/outerwear,and stock engine internals. I had 6-8 holes in the airbox lid, 300 main jets, the rest of the carb internals are at factory settings. In the winter, all I had to do was plug the holes in the airbox lid to prevent a too lean condition. Yamalube 32:1 With these settings the bike ran awesome and I never had to rejet. I was going on two years with the original top end, then I rolled down a hill and busted the case on a rock! Hope this helps...
Addict

 

What would the symptoms of it running lean be, in the summer when it runs really well be, other than a burnt topend?

Also, how much bigger should I go on the jets for the winter, and what jets do I change?

Over Christmas vacation from school, I think I will take a look at the carbs, and if someone tells me how I can determine the size of the jets that would be helpful, then I could post them on here and you can tell me how that sounds for where I am and what I have on it.

Thanks alot for your help. I am going to try and resist not riding it until it is straightened out, I would just love to tear my topend apart again, over a simple problem like this!!

 

Buy a manual, READ IT, do a plug check, and go from there. We really can't jet your machine for you over the net. The jets size is marked on the side of them. You really need to do some research and read up on jetting and basic carburator principles. All I can tell you is it sounds like you are lean. Ask a fellow rider, or the local shop for a baseline recomendation and they will probably help you out. Take notes. Good luck.

 

For your mods try the following:

1) Install 30 pilots with airscrews 1.5 turns out.
2) needles in middle (stock) position.
3) Start with large jets: ~340 mains for your mods and temp.
4) Warm bike thoughly. Attempt high speed runs. If it comes up on the pipe and does not burble, install the next larger size mains ( 1 size = step of 10). Repeat until it burbles.
5) Once it burbles, drop one main jet one size at a time until it stops and runs cleanly. This is the optimum jet for that temperature and altitude.

Some people will say that this is too rich. I contend that this is the SAFEST jetting method. Doing it this way will insure that you will not be too lean on top. Too rich will not hurt the motor; too lean will fry it over time.

Trying to read a plug is asking for trouble. Did you know that to read a plug you have to look where the insulator meets the shell? If you look at the insulator tip it will give you a false reading. In my experience the only time a plug shows lean is when it is VERY lean.

 

Sik_Banshee thanks for the great reply and help,

Here are my questions for you,

1.) As far as the 30 Pilot and 1.5 turns out on the airscrews. How will I know if these need to be changed, and how will I know what way they need to go. (bigger/smaller, turn out more/in more) This affects 1/4 throttle, or am I wrong?

2.) For the mains, how do these change according to temp. When Spring hits, do they go up or down and usually about how much on the average?

3.) Elevation will also affect these settings, correct? Well if it helps any, I am at about 1000ft. above sea level (according to my dad). Is there somewhere I can look this up at?

4.) Recently, (past 2 times I rode it) it has been running well. The only problem now, IS GETTING IT STARTED! Starting it cold is no problem, but once it is to opperating temp. and about 30mins of hard riding, I shut it down (park on a hill of course in case it won't start) and when I go to start it up, it won't kick over. I am catching it in gear 9 out of 10 times! It isn't overheating much at all, and if it does, only alittle will run onto to the pipes. The changes in jetting sizes and settings should straighten this right out for me, right?


My friends Banshee keep overheating today. I mean badly over heating. I was far away with my friend and saw a cloud about 30feet overhead of his banshee, pull up and this thing is spewing it like no other I've seen. It happened on more than one occation, and later tonight he ended up getting pulled home. I sure hope he gets his straightened out! It must be even leaner than mine is? But his actually kick starts up, easier than mine and only once tonight did he have to get it pulled to start. Mine, will never in this cold weather, but I'm not overheating anywhere as near as he is. I don't understand?? Do you?


Thanks for your great help, sik_banshee! I really appreciate it,

 

The pilot affects 0-1/4 throttle. The airscrew affects idle and just off idle. With pipes the 30 pilot should be OK all year and you could even go to a 35. 1 1/2 turns on the airscrew is a starting point. Adjust for best idle.

There are charts for the effects of altitude and temp. I dont have them. I usually just ballpark it. I ride at sealevel and 7000 ft. At sea level I run 300 mains and go to 280s at 7000. All other settings remain the same except slight adjustment of airscrew. For temps from 70 - 100 I keep this jetting. For 40 - 70 I go up a size on the mains ( I live in AZ so don't get to ride in much cold weather!)

If you jet now for cold weather your jets will get smaller in warm weather.

This info is for running w/o the airbox lid (using a pro-flo adapter). If you run with the lid your main jets will drop about 3 sizes.

 

I am running STOCK pipes with DG silencers (the way I bought it) Soon within a month I shold have pipes and silencers, like toomeys or ct racing. I run with the air box lid, and with a k&n.

What are your suggestions, should I go to a 340, or stay down around 300?

 

By the sounds of it it sounds like its running just like my banshee did before it blew up, would be a hard start then when you got it started it would only run in the powerband, otherwise it would bog down until you gave it the gas and got the other cylinder firing, If I were you I wouldnt be riding it at all until you get it fixed, I rode my banshee like that for about a mile and it siezed big time. If the cylinders arent firing right I wouldnt touch it, get it fixed. here are a couple pictures from the inside of the banshee when it blew up
http://www.geocities.com/yamahabanshee96/right.jpg
http://www.geocities.com/yamahabanshee96/left.jpg
http://www.geocities.com/yamahabanshee96/head.jpg
http://www.geocities.com/yamahabanshee96/cyl.jpg
If you appreciate your machine get it fixed before it ends up costing you a ton in repairs