Spark plug.

[gasgasman]

Ever since I've had my 2011 250 SD GasGas, it has had a wierd burble in the mid range.
Sometimes it would run fine. But was annoying.
The RB carb and head mod made the bike run much better. Which led me to believe it was a carb issue.

Finally I said I need to get to the root of this. So, with the help of a buddy of mine I started changing jets etc. He recommended to go to the extreme on the jetting to see what changes can be made to the way the bike ran. Jetting did not help.
Then he said, try a new plug. So I put an NGKBR8EG. The bike runs like a scalded ape now. The rain mode runs just as well. So blubbering at all.

I was talking to another member here who was having the same issues (2010 300). I called him to tell him what I found and he just happened to put the same plug in this past week and his bike runs like a top.

Moral of the story. Be sure to install a BR8EG plug in your bike if you have any running issues.

 

[noobi]

What were you running?

 

[GMP]

Girard,

Thats funny, mine (all three 250s actually) runs hard with the el cheapo BR8ES it has had in it all year. Think it was the "G" plug or just a new plug? What was in it before? Theoretically the fine wire plug should have less resistance from less electrode area to form a leakage path.

Are any other wires routed near the coil/HV wire?

 

[gasgasman]

It was the OEM plug. I'll look when I get home tonight.
I don't think I have any EMF issues. I mad sure not to disturb any wires etc. when I swapped plugs.

It is ironic that another bike here in Houston was having the same exact issues. The dealer he bought the bike from was here for the Caney Creek Enduro and he swapped CDIs,removed the map switch etc. with no change in the way the bike ran.

What threw me for a loop was how well it ran below 1/2 throttle.
Plug had a nice tan color to it.

All my other Gas Gas' would run perfect on any plug I threw in there.

Last weekend, we rode in a massive down pour. Bike ran like a top.

 

[Jakobi]

I know a few people here in Australia who have had same issues with the stock Denso BR8EG. They also find the NGK works much better across the board BR8ES/EG/EIX

 

[GMP]

The spark energy is whats left after the loss in the resistor cap and resistor plug. Perhaps the Denso plug has a higher internal resistance? Just for kicks try a new NGK BR8ES, and a new B8ES non-resistor plug. I have never had a non-resistor plug interfere with a CDI, just froze up my ICO once (on a KTM300), or at least I suspect it did.

I always go over the wiring in a new bike and reroute as neccessary to avoid chafing and to keep things as far away from the coil/HV wire as possible. The new bikes with the vertical coil mount might be a little different, I don't know.

 

[TNT Cycle]

the denso is listed with a broad heat range in most catalogs. I think most don't know how to handle the denso or have unclear info. Parts catalogs I've seen will say u can run the denso that came with my 2010 300 for BR8XX, BR9XX, BR10XX but never say what heat range it really should be. I think that has something to do with it.