Hey guys..kinda new here. but i've got a problem with my 86cr250 that was running good for a while after i rebuilt and broke it in. and it was smoking a little bit but i did mix the fuel rich so it was during the break in. but now its smoking (seems to be worse) and i've never fouled a plug on this bike and it went through 2 within 2 days and its losing power. Oh and it also "chokes" when it hits higher rpms. it'll hit powerband when it wants to it seems. Thanks for the help guys.
CR250 excesivly smoking + fouling
- Thread starter Eddels509
- Start date
- Mar 8, 2000
- 1,993
- 7
Sounds like the primary gear bolt has loosened up allowing primary gear to back out of the seal.
BraapBraap214
Member
- Nov 10, 2009
- 6
- 0
you have a broken crank seal, there is nothing else that will produce smoke, gas doesn't burn blue and you can't burn oil rich if you don't mix it rich, so the oil is coming from somewhere else. It's more common for the clutch-side seal to go first, but since you have to get in there anyway you might as well replace them both. Good luck!
Float valve or right crank seal. A leak down test can solve the seal issue. The valve, well it is a yearly replacement item. It can puke fuel into the motor when least expected, and not onto the ground, till the pipe fills up, or leaks. Vintage Bob
Brandon H.
Member
- Mar 26, 2009
- 199
- 0
Just wondering, since I don't own a leak down tester, if I wanted to check for bad seals, then could I screw in a fitting in the spark plug hole and add very little air (like 5-10psi) and then spray soap water on the seals and look for bubbles??? Just wondering?
I suppose, but, do not go over 5~6 psi. I do not recall the amount of time for leakage, its in the directions! If it will not even hold pressure at all, you found 1 major issue. Fleabay has a smoking deal on a wiseco bottom end rebuild kit. Vintage Bob
- Thread starter
- #8
thanks guys. i'm going to try to get the crank seals replaced tomorrow :) we'll see if it fixes the problem. if not. what should i look to next? also any good performance plugs anyone live by? i know about ngk's and such but i'm looking for a real real good plug. and if anyone's in the spokane, spokane valley washington area and know of any good spots to ride.
The best plug is the ngk that belongs to the bike. BR8EG is the cheap plug, you can use the br8es to jet with, then there is the meteor plug BR8EIX?, http://www.ngk.com/results_appOther.asp?otherMotiveID=225027&mfid=1 . Vintage Bob
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