2nd Crank seal in 1 year?

[sangheraent]

I was installing my timing adjuster today and when I drained the oil I noticed it was fairly low. I did my job poured new oil in up to the drain hole and then my bike started smoking more then normal. the more gas I gave the worse it got and after about 10 minutes it got really bad.

What causes my crank seals to go bad? this is my 2nd crank seal in a year I have about 20 hours on the bike since that seal change I don't understand what would cause it my bike runs perfectly.

[Deadly]

Well they are man made and bound to fail sooner or later and this might just be dumb luck. However you could also have bad crank bearings and/or there comes a time when the bearings don't quite sit in their seat tight due to age or incorrectly putting in a bearing and they will slop around. Any slop and it will prematurely wear that crank seal out. Pretty easy to find the slop if you grab onto the end of the crank and see if you have any up/down or side/side movement.

There's was a reason why Honda went to an 8 ball bearing instead of reusing the same old design (7 ball bearing). If you are unfortunate to have slop i the bearing seat your pretty well screwed.

Let me also ask, do your inner casings match? I had heard there was a small difference that makes things not quite lineup properly.

[Grande Huevos]

if you push your seal in too deep during the install it will rub on the bearing which will destroy a seal in no time. just one possibility

[KM250R-BDTM]

Make sure the crankshaft 'shaft' is clean and smoth with no corrosion. Also make sure the bottom end has no foreign matter floating around. Assemble the seals with grease on the ID lip area, and always use OEM seals.

The Left side seal sits 6MM deep and the Right side sits flush.

BDTM

[fearlessfred]

the collar that the seal rides on can get groved and a new seal wont last long and as allready stated ,bad bearings