Two Stroke Motocross

Two Stroke Motocross Forum => Technical => Topic started by: CRLover on March 13, 2011, 03:46:27 PM

Title: fouled plug
Post by: CRLover on March 13, 2011, 03:46:27 PM
Well my first ride of the season didnt go quite as planned.  I fouled a plug right off the bat.  Luckily they had an accessories shop at the track office, where I bought another plug. The bike fired right up and ran great for an hour or so, an then after a little water break, I fired it up and I rode about 100 feet and that new plug fouled. So I tried to clean it  but no go. So I gave up for the day.    Does anyone know why the plug would foul like that ?  I never had a problem B4.   Last fall the bike ran great.  I think Im gonna do a little jettingchanges to see wat happens. Any help would be appreciated.
Title: Re: fouled plug
Post by: CRLover on March 13, 2011, 03:51:59 PM
Forgot to say  I ride a 2002 cr 125    I opened up the air box with 4-  1" air vents, and a new 2006 air boot.           But I didnt think I would need to rejet for those small changes. 
Title: Re: fouled plug
Post by: TMKIWI on March 13, 2011, 04:41:46 PM
Pull the carb and check for stuck float or choke.
Seems strange if it has the standard jetting.
But it must be getting too much fuel if the plug is fouled.
Title: Re: fouled plug
Post by: SachsGS on March 13, 2011, 05:28:52 PM
"The first ride of the season" part of your query caused me concern.Do you live in an area where your bike is exposed to very cold weather?If so it might be worth it to have your ignition checked out,I've seen many a cracked stator as a result of freezing.
Title: Re: fouled plug
Post by: Coop on March 14, 2011, 04:03:29 AM
Were you using fresh gas or old stuff leftover?
Title: Re: fouled plug
Post by: MyckMcClung on March 14, 2011, 05:04:21 AM
I have had fouled plugs due to, filter rim grease, bad gas, bad crank seals.
Title: Re: fouled plug
Post by: CRLover on March 14, 2011, 04:16:42 PM
Thanks 4 all the advice  I will definately check all that stuff.  It was fresh gas  93 octane with yamalube  32:1        I usually run 40:1  but with a new top end I wanted to add a little extra oil for the first ride.  That might be why Im fouling plugs?!?!?   I should have it fixed  by the weekend
Title: Re: fouled plug
Post by: chump6784 on March 15, 2011, 03:03:35 AM
32:1 is fairly rich. its funny the manufacturers recommend that but i dont know of who person that actually runs it or at least runs it for long. the richest i have ever run a bike is 36:1, normal is 40:1 in an RM125 and RM250
Title: Re: fouled plug
Post by: ford832 on March 15, 2011, 04:20:11 AM
If the temp is much warmer now where you are than it was in the fall,it could well just be too rich.If not,other than cleaning the carb,I'd leave the jetting alone and follow some of the above advice.You don't want to generate another problem on top of what you already have.
Title: Re: fouled plug
Post by: Coop on March 15, 2011, 05:14:10 AM
32:1 is fairly rich. its funny the manufacturers recommend that but i dont know of who person that actually runs it or at least runs it for long. the richest i have ever run a bike is 36:1, normal is 40:1 in an RM125 and RM250

I run 32:1 in ALL my two strokes.

I agree with ford. (Yikes I really just said that...:) )
Title: Re: fouled plug
Post by: MyckMcClung on March 15, 2011, 05:57:59 AM
Back when I was running Klotz I would run at 40 or 50:1, but now that I'm running the Lucas I and have all these small bores, I'm running 32:1 no jetting required.
 Was the plug  black and sticky?
or just wet?
Title: Re: fouled plug
Post by: MyckMcClung on March 15, 2011, 05:58:56 AM
Also what heat range plug is it that fouled 8,9 10???
Title: Re: fouled plug
Post by: CRLover on March 15, 2011, 07:10:38 PM
plug was black and wet, dont know how sticky it was.   Running a NGK br9eg resistor
Title: Re: fouled plug
Post by: ACMX on March 16, 2011, 11:23:37 PM
I'm a budget racer. I run 32:1 to maximize the life of the bike, sacrificing a small bit of power is fine.
Title: Re: fouled plug
Post by: TotalNZ on March 16, 2011, 11:48:37 PM
32:1 is fairly rich. its funny the manufacturers recommend that but i dont know of who person that actually runs it or at least runs it for long. the richest i have ever run a bike is 36:1, normal is 40:1 in an RM125 and RM250
I run 30:1 with no problems. Plug fouling's not an oil ratio issue.
Title: Re: fouled plug
Post by: TotalNZ on March 16, 2011, 11:50:11 PM
I'm a budget racer. I run 32:1 to maximize the life of the bike, sacrificing a small bit of power is fine.
I don't believe you're sacrificing power at all. More oil more power i reckon.
Title: Re: fouled plug
Post by: MyckMcClung on March 17, 2011, 05:19:15 AM
More oil will not sacrifice power, it will not cause plug fouling, it just makes more spooge to clean up.
"Black And wet" huh?
If that was a new plug your crank seals are weeping buddy
If were sticky it would be from filter rim grease
If it were just wet, ignition problem
Title: Re: fouled plug
Post by: TotalNZ on March 17, 2011, 09:46:09 PM
I do'n't get any spooge because my jetting's good.
The oil comes out of suspension in your crankcase and more oil to the bearings is a good thing.