I have a theory on all this plug fouling...
Posted November 07, 2000 - 05:51 PM
Anyway, here is my theory...
I've noticed I would foul plugs shortly after starting the engine. The last time it happened I just got all suited up and started to head out and on came the snarling and poping. My theory is these carbs shoot an unbelievable amount of fuel once the throttle is opened, and could it be this stream of fuel are heading into a cold cylinder and plug with no hope of vaporizing. I was quite impressed with the distance that stream shot when I had my carb off to do my changes.
So, lately I have been going with a new procedure by starting it and letting it idle just long enough on choke until it will idle on its own with the choke off. I then let it sit and idle until the cylinder head is quite warm to the touch and only then get into the accelerator pump. Maybe we're getting a bit anxious with these "squirter" carbs (never had one before!)
So far, no fouled plugs! Any thoughts???
Posted November 07, 2000 - 05:55 PM
Posted November 07, 2000 - 06:15 PM
Posted November 07, 2000 - 09:31 PM
I aggree with all of your ideas - getting the choke off early, warming it up good, and not over-twisting to warm it up which squirts raw gas in.
Your switch from DTM#4 to DVP#4 has broad effects some readers may not realize. DVP#4 is larger and leaner all accross the range and is an appropriate size step to make. Thank Clark for that one.
Posted November 08, 2000 - 09:27 AM
Posted November 08, 2000 - 12:28 PM
Measure your carb needle to confirm your sanity .
Get some calipers and measure your DVP needle diameter, the straight portion should be 2.735mm (.1077in). Then set the calipers to 2.50mm and hold it horizontal. Compare DVP and your stock needle together by letting them rest gently in the slot. Look at the relative clip height.
A stock '99 DTM needle will rest EXACTLY 1 clip position further down than DVP.
A stock '00 DRS needle will rest EXACTLY 2 clips down, it is 2 clips richer at mid throttle.
If your needle rests 5 clips lower, it is actually a DKP needle!! and is mis-marked. This would force you to the leanest possible clip position.
--We can hold weekly meetings for those interested in "jetters anonymous". ... Hi I'm James, and haven't fouled a plug in 5 weeks... .... Now I can enjoy riding again.
Posted November 08, 2000 - 02:45 PM
thanks to clark i changed to a 48 pilot 3/4-1 turn out and now she starts much better and stalling is almost gone completely, i noticed that the nipondenso plugs dont seam to self clean as well as the ngk's after being flooded just my 2 cents worth.....
Posted November 08, 2000 - 05:50 PM
Then again, maybe I won't have to worry about our favorite topic anymore. One can hope!
Posted November 08, 2000 - 08:29 PM
Posted November 09, 2000 - 03:45 PM
2000 Yamaha WR400F
1988 Honda NT650 Hawk
1977 Suzuki RM250B
1974 Honda XR75K1
Posted November 09, 2000 - 04:44 PM