I am having problems with my 1999 Banshee fouling out plugs as fast as I can put them in. Actually it is only fouling the right side plug. I mix Yamaha oil 32:1 with NGK B8ES or BR8ES plugs. Does anyone have any suggestions on what might be the cause of this?
Thanks
David

 

1st I would check your compression. Then I would look into a carburation problem, float level, jetting. How does it run otherwise? Does it smoke bad?

 

I can tell you this , if you putt around alot like on the trails , you will foul alot of plugs the banshee wants to be wide open and going fast, when you go slow alot and are not winding up the throttle it will foul plugs left and right. Next put in a new plug and ride around for about 5 minutes take the plug out if it is black your to rich , check your jetting. Just my 2 cents .

 

Must be running rich on the right side. As blaster said before, do a plug check. Are u gapping the plugs? I know a few people who just leave the gap normal, and that is a BIG mistake. The gap that comes on it is 50% smaller than what the gap should be. A normal B8eg comes with a 15 gap, and your supposed to have anything from 28-32.

What color is the plug on the right? I am almost thinking it could be an air leak. Was it a white color, or dark brown/black?

You are going to want a honey brown color. Just rejet a bit leaner until u get the right colors.

-nick

 

First of all, the Banshee should virtually never foul a plug. I fouled 1 plug in 3-1/2 years on my Banshee and that was last week. Don't know why I fouled it - it just started up like normal then 1 cylinder started backfiring and not running right - I replaced the plugs and it was fine.

Anyway, it is a good idea to check the gap. Otherwise way too much oil or too rich a mixture would do it. You can try a slightly hotter plug (I forget if hotter is b9es or b7es???). You can try swapping the plug wires and see if the problem moves to the left cylinder.

Sometimes I just putt around at idle in first gear taking my son around the yard or something and it is fine. Again, fouling plugs is not a normal occurance. I run a set of plugs for 1 year then buy new ones.

 

Thanks for all the input. I will try some of the advise here.
Compression check
Visual Check of the plug when not fouled
Gap setting
Hotter plug
The bike runs great when the plug isn't fouled. Both sides smoke a bit until it get warmed up. Does anyone run a leaner mixture than 32:1?
David

 

32:1 with Yamalube is perfect. I wouldn't go leaner than that - it's what I run and my compresison is good and cylinders are smooth after over 3 years.

 

Do a leak down test to be sure your transmission seal isn't going bad. I have run Yamalube 2R at 40:1 and Belray MC-1 at 50:1 with no problems and after 4 years the cross hatch marks are still on the cylinder. I've run from day one with these two oils. As Wyoduner said I never foul plugs. I had my stock plugs in mine until the beginning of this year and I changed them out finally because I wanted to, not because I had to. I still have the stock plugs as spares. You have other problems if your fouling plugs as fast as you can put them in. I've even let my girlfriend ride my Banshee with the throttle limited fully and she putted that thing around for half an hour or so and when I got back on it not one problem starting it.

 

The bike is leaking transmission fluid. So if the transmission seal is bad it will cause plugs to foul? Could you be more specific about what a leak down test is or provide a link that explains it?
Thanks
David

 

Ok to do a leak down test you need to seal the intake and exhaust as well as the spark plug hole where you normally have a pressure guage. You then pressurize the motor to about 5-6 psi. After a period of time (10-30 mins) you come back and you check the pressure and see if it has dropped. If it has dropped you have an air leak and one sign of a leaking transmission seal is the right side plug fouls. Guess what side the transmission seal is on? Makes you wonder why the right side is fouling but not the left.... because the left side houses the stator which isn't bathed in oil like the right side case. Check out www.macdizzy.com for more info on the leak down test and a kit so you can do a leak down test.