520 sparkplugs

The other day I gas fouled the original sparkplug in my 520 EXE. My fault, since I didn't let the bike warm up, but it required a new plug before it would run again. Is there a better plug then the OEM version? Is this a common problem with the RFS motors?

the RFS' come with a very good plug from the factory, it's the same plug that my TL1000R and many other sportbikes come with.

My bike came stock with an NGK-R. It's a pretty good plug. I've always raced with NGK plugs, with good results!

I'm begining to wonder if there isn't something else wrong. I've dropped in two new plugs and niether has got the engine two fire more than a few seconds before I'm back to a fouled plug. I've cranked the engine with the plug out to help clear it, kept my hand off the throttle, etc. I've done this with and without the tank on (since it a pain to get plug access when mounted) thinking the float bowl might be running dry. The bike ran fine until it sat overnight at a race site. It couldn't be someone fooled with it?

?? And you're fouling plugs?

I ran my bike accidentally for almost 2 minutes, under load, COLD, with the choke on. She stalled on me when I stopped (I was riding up to claim the TTR-90 that I won, and I was so amazed, that I left the choke on). BUT, she re-fired with a few kicks. I've also stood there, with my throttle wide open, engine cold, and not running, only to have her fire up after 2 kicks. My Accel Pump is shooting a continuous jet too.

Perhaps you have a weak igniton, or something electrical wrong? Is the gap OK? Too far, and it could act like a weak ignition I think. I can't believe you should load plugs up, really, at all, on a 4 stroke.

My stock plug was an NGK as well, and it was dual tipped, ends opposing (i assume everyone else's is the same!). I only replaced it when I did a valve adjust (after 5 months) because I noticed the center electrode was actually worn away.

But, if the plug is fouled, it's either getting too much fuel, not enough air, or a crappy spark.

[ November 21, 2001: Message edited by: Chris Slade ]

I am getting out the tow rope today. will keep you posted.

Never thought about it but I'm on my same stock plug whatever it is. I have about 1500 miles on it.

Well, after about a 100 meter tow, the bike started and throughout the day started and ran fine (warm). Tomorrow I'll try a cold start (temps in the 30 degree F)and see how it goes. I rode at the ISDT reunion ride in Missouri last month. Malclam Smith's (yeah, Mr. MSR)520 EXC needed help to start after cranking the battery dead on the line. Temps were in the high 20's and they finally got it started after 15 min. Fortunatly I rode my '74 YZ-250 (three kicks max. hot or cold).

Turkey day, low 30's, choke on, pushed the button, and it fired right up. I wonder if while the bike was sitting over night at the race site if people were walking up/talking, twisting the throttle and flooding the engine? Hmmm.

If you question if the bike is flooded or not...do this routine (recommended on a warm day only, as the engine will most likely be starved for cold oil )

For flooding -

1) Pull compression release in the whole way.

2) Hold throttle WIDE OPEN. WIDE OPEN!!!

3) Kick HARD (yes kick, sorry fellas) approximately 10 times. The bike will fire around the 7th kick or so, under most circumstances.

Now mind you, back off the gas and release the comp. release lever as soon as she fires, because with the gas wide open, she'll rev out before you can blink, and if the oil is cold...well, you know all about high rpm with no oil, right?

Worked for me the time at Elsinore I had my clutch cover gasket go leaking...we layed her on her side for over 15 minutes, gas on and all. SHe wouldn't fire. My uncle (the same one that owned a shop) told me to do that technique. He uses it on his Husky's. It worked no problem.

Recommend the kicking, in case the valve is going to hit the piston, you'd feel it and hear it kicking, whereas if you use the e-button, you could smack it into it without realizing it!

[ November 22, 2001: Message edited by: Chris Slade ]

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