Hotter Spark Plug?
 

Running a 2002 ec 300 with a full Dep system, powervalve spacer, 0-500ft.

In normal operation the bike runs strong with no bogging and hesitation, and very rarely fouls a plug, however did a enduro at the weekend and was running in 2nd 3rd most of the time rarely getting into the powerband, and i must of gone through 8 plugs in the 3hr race! Spoke to my mate after who is rides a rm 250 and he didnt have a problem at all , but mentioned that he was running a hotter plug just for that race as he knew it would be rutty and slow.

So my question is can we run a hotter plug in our bikes or is it not an option? would it be better to change the jetting for the race?

For the past few months I have been running a BR7ES which is 1 step hotter than the standard BR8ES. I tried this to see if I could get rid of the slight fouling/hesitation that occurred when winding open the throttle after a patch of slow running. The result is some improvement but the hesitation is not entirely gone. I have not had any bad effects.

I started now run enduro after one summer of mx on my Gasser.
First times I opened wide and to the powerband, it started bogging and didn't take rpm. So I opened the air screw from carburetor for 1/2 turns and it helped pretty much. I've also thouht about a iridium plug. It should maybe help bogging.

A hotter plug is fine unless you run wide open throttle alot.

Thanks for the answers guys going to buy some Br7's and some Br6's and have a bit of a play to see what the difference is.
Will let you know how i get on.:)

plug
 

I switched to a 6es after a plug foul about 2 years ago, I still run on the same plug. About 4000 km without a problem. Hope this helps

So if I run mx, I would be able to go for a BR9 plug to run engine cooler?

I have no problem with a BR8EIX,in my 08 and I ride tech stuff with a lot of bogging around. plug has good tan color
I think your jetting is off and a hotter plug is not the way to remedy that.
You may try a different needle like a cck, or start by dropping the needle that's in there see if it cleans up some....if so and you run out of clip positions then a leaner main jet may next.

I just tried a BR8EIX for this season. We will see if it's worth the $. I only use one a year so it's not really an issue.

I agree with above though, a different plug is not the way to address jetting issues. Work on your jetting to solve the issue.

Check your float level, these bikes are known to foul plugs if it gets off just a bit. I think part of the problem is the carb is hard to keep level as the tank wants to twist it to one side. Drop your float level just a tad and see what happens before you change plugs. My sons 250 would foul his plug every time he went down a long hill. No problems at all now. Whatever you do I wouldn't go past a 7, starts getting risky. If its jetted right it won't need anything but an 8. Don't compensate one problem and create another. :D

Does not make your engine cooler, it means your plug doesn't get as hot. If you run wide open all the time like in an open MX or desert race you may want to run a colder plug to prevent pre-ignition.

Think everyones getting the wrong idea here..

nothing wrong with my jetting, bike pulls cleanly at any rev, with no hesitation or bogging, dosent foul a plug.

what i was asking was on the very few occasions that i race in tight woods where you are not getting into the power, i asked if it would harm the engine to run a hotter plug for that race rather than go to the hassle of changing my jetting.

Im in the UK where we havent got lots of space to ride so tracks tend to be very tight and twisty, and being as i dont race that often my bike is not set up for that particluar enviroment, mine is set for trail riding.

What did you mean when you said you went through 8 plugs if it doesn't foul a plug?

Dosent foul a plug in normal operation.. Had the same plug in the bike for 6 months no problems, the problem came from one particular race in a wood with very deep ruts where you couldnt get into the power.

And my question originated from a riding friend, who suggested changing to a hotter plug just for that particular race.
I was just wondering if it could be done with out harming the engine, as i dont particulary wish to mess with my jetting for one 2hr race.

You can go one stop hotter and be fine, but I still bet you have a jetting issue somewhere around 1/4 throttle. It shouldn't foul 8 plugs in 2 hours. Start here-http://www.keihin-us.com/am/_media/pdf/slide_valve.pdf

so if you ride mostly tech stuff where you are hardly off the pilot jet you could go for an 8 or 7? I have noticed that often on the riding i do i come out of a long tech stuff onto a track and open up the gas and the bike splutters a bit (like a cold engine) before it kicks into powerband

This caused me to flip at the last race because i cam out of a tight section to a v steep climb with a short run-up so i opened it up at the bottom but the first few meters of run-up were used up by splutter and i was trying to get going on the slope. second attempt was fine :)

Also GG recommends a BR9EG for my bike, I cannot get these at the moment as the bike shop is out of stock, what would be the implication of running a BR9ES? or BR8Es if i decide to go slightly hotter

Hot plug is a bandaid for bad jetting. I run the basic cheap BR8ES with good jetting and 36;1 mix, in very technical stuff, and have no issues. I could run the plug for an entire season if I want, I just pull it occasionally to check.

If you want to run the correct heat range but want a plug that is less prone to loading up, consider running a projector nose plug. NGK BPR8. It will tolerate poor jetting and low speed fouling much better than semi shrouded types.

yes i did that too on my 300 i see you leave in a hot country like me and i was so fed up with the jetting around problem and went for a hot plug 6 but strange enough i could not get high rev power.i have 35 pilot and 168 main with cck needle.i think i will try the float level.my 250 never had an isssue like this.