Front Bearing Leak

  • I have a leaking front bearing. When the engine is cold it is fine,has no or so small of a leak you can't tell and has tons of compression. However, when it gets warmed up it loses compression and gets extremely hard to crank. You may ask how I know it's leaking from the front bearing, I keep my rig super clean and could see where it leaked there.

    My question is what can I do to stop this leak? I ordered a front bearing this week, my LHS told me that the Sportwerks 26v2 front bearing could be problematic. Anyone got any tips or suggestions?
  • Usually a front bearing leak is caused by an engine running too rich and dumping excess oil through the bearing. How's your tune? It might be work checking.
  • I think my tune was at least close, but I will check it
  • Its not even worth messing with just put a new one in. I use cheaper ofna/japan bearings(front only) and replace them every gallon. Keep both seals in the bearing and pre-oil the bearing with a good synthetic oil.
  • I would like to be able to order my own choose of bearing but am not able due to my lack of knowledge. I don't know what size bearing my engine takes and I couldn't find a part number. My LHS ordered me one but like I said, I would like to order my own.
  • Most engines use a 7x19x6...check it when you get the one from the LHS. Our ceramic uses 2 seals to eliminate leaks.
  • Quote: However, when it gets warmed up it loses compression and gets extremely hard to crank.
    I think we may need some more information on the condition/age etc. of your engine. Isn't the partial quote above some kind of evidence of a worn piston/sleeve? It explains the fuel pumping out after it is warmed up.
  • Two gallons through it never had any probs till last week and I pulled my engine out and saw where it had been leaking from the front bearing. I pull my engines pretty reg. to clean and have never seen any evidence of a leak before. I wiped everything clean before tearing it down, after run oil leaked out of bearing. Tell me if there are any other conditions you need to know of to diagnose. Thanks

    Oh yeah the losing compression and not wanting to crank. Piston and sleeve are fine.
  • I am replacing the front bearing with a good quality ceramic? Since I am two gallons in should I replace the rod?
  • Is the engine running OK? If so do not bother. Many motors will have slightly leaky front bearings after they become worn. IF it gets bad enough that you cannot get your motor to tune then replace it. I have had motors run fine for a couple of gallon after I start seeing damp dirt stuck around the front bearing & behind the fly wheel. Peter Martin has given you the standard front bearing size & their TKO bearings are a good choice for aftermarket bearing replacement. Also as he stated, double sheilded is always best for off-road. Oh ya, the leak in your front bearing has nothing to do with your compression issue.
  • Yes the engine runs great it's just hell to crak afterwards. I finally got enough time last night to finish tearing my engine down and measured the bearing. It was the standard 7x19x6 and I ordered their TKO Ceramic last night. Thanks for the info
  • I like to check my pinch, not compression.if you take out the glowplug and turn over the crank with your fingers and you dont feal any pinch, the piston and liner are probably gone. it only takes a lean mix for a good days racing, or suck some dirt in to junk the piston & sleeve. all im saying is...compression means little to nothing on this kind of motor.

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