CR250 LH Crank Seal question

[XXX Adrenaline Spo]

Has anyone ever seen a LH Crank seal leak and everything under the mag cover be clean and dry? I mean spotlessly clean No residue or anything at all. I have not removed the flywheel or plate to take a closer look but the entire area is spotless. Ive been under the understanding that if this seal were leaking that things would be kinda wet & nasty am I right? I DO have a problem with a Lean condition way down low and way up high (Powerband wise) but midrange is always about right, I have rejetted and rejetted and rejetted and.......well you get the point. Can anyone give me any ideas on this? Id hate to change this seal for no reason. If I "lug" the bike and check the plug its black, If I give it a little Braaap its tan (Almost perfect), If I let it scream its white, White like WAY too lean, If I ride a Harescamble (Where I cant check the plug every 5 min) it goes ying ying ying when I let off the gas in the woods but only after about an hr into the race does it start doing this.

BTW, Everything around the cylinder, reeds, intake and carb are clean and dry as well (I have had a leaking reed block before and know how dirt accumulates around the leaking area)

Someone please help

:bang:

Thanks,

Stuart

 

[aaronnaland]

I have never seen one spotless but it might be possible for it to do it. How do you know you have a bad seal.

 

[XXX Adrenaline Spo]

I dont know I have a bad seal. Im trying to figure out the lean conditions. was wondering if anyone has seen a lh seal leak and the area still be clean.

 

[aaronnaland]

I would say you dont have a leak.

 

[Matt90GT]

What is your jetting on the bike right now? The 01s are not the easiest bikes to jet.

 

[XXX Adrenaline Spo]

I just put a JD Jetting kit in it with their "Special" red needle, 400 main, s-4 nozzle and 32.5 pilot, Well now it has PLENTY of power (More than b4) but still lean on top and bottom

 

[_JOE_]

Spend a couple bucks and have a leakdown test done. Leave the igintion cover off so you can listen for air if there's a leak. If that's not it I might look up through the needle tube that the main jet threads into. I guess it's possible some junk could be accumulated in there restricting the flow above the main jet. That's probly a shot in the dark.

My JD warm temp needle is pretty lean. I've not yet tried the cold temp needle, but think I might this season. I'm now at the full rich clip position with a definate difference in response and pull from the next one up. How far from stock are you on the main and pilot?

If I "lug" the bike and check the plug its black, If I give it a little Braaap its tan (Almost perfect), If I let it scream its white, White like WAY too lean,

Why do you think the pilot is lean?

 

[XXX Adrenaline Spo]

I think the pilot is lean because it "Ying-Ying's" when I let off the gas in the woods after getting fully warmed up

 

[_JOE_]

Make sure all the exhaust joints are tight. Have you swapped brass for something a few steps different?

You should see some residue around a leaky left crank seal. The crankcase is also pressurized so if it's leaking it should let some oil out.

 

[XXX Adrenaline Spo]

Everything Everywhere is clean, dry & tight. This thing beats me. Maybe the noise was just..............I dunno
:bang: :yikes: