main bearing removal


7 replies to this topic
  • new_rider3436

Posted March 14, 2007 - 06:24 PM

#1

alright i have the crankshaft out(used the tusk case splitter:thumbsup: now i need to get the main bearings out....can i do that w/o a press?
thanks

  • KDXGarage

Posted March 15, 2007 - 10:25 AM

#2

You may need a bearing puller.

  • scot_douglas

Posted March 17, 2007 - 08:43 AM

#3

alright i have the crankshaft out(used the tusk case splitter:thumbsup: now i need to get the main bearings out....can i do that w/o a press?
thanks


You can use a bench vise and a socket to press out the bearing. Make sure yo have some wood between your case-half and the vice jaws on the back side.

Also, you can take a heat gun and heat the case area around the bearing before pressing it out.

Since I've just done this on a kx100 myself, here are a few more tips:
-freeze your new crank bearings, crank seals and crankshaft overnight.
-thoroughly clean your case halves and bake them at 250f in your oven for 30 minutes.
-use your old crank seals to find a socket that will fit over the seal lip, but inside the outer "race" (the part that will hold it in the case).
-use the socket to press in your (frozen) seals by hand. They should easily seat in the hot case. (dont forget to wipe a thin layer of grease on the seal surface to initially lube the crankshaft install
-the (frozen) crank bearings should drop right in the case. One side I had to help along with a plastic mallet.

I think you also sent away for the tusk crank press (like me :lol: ) -- well, it works on the output/generator side of the crank, but it does not work on the clutch side. :eek:
It needs to be able to thread into the end of the crank - the KX crank is too small to have a threaded hole for a bolt to hold on the gear (remember the circlip we had to remove to get the gear off the shaft?).

Here's what I did to get my cases back together:

after the seals/bearings were installed, I test fit the transmission and made darned sure I could install it quickly.
Then, I took a tapered impact socket (craftsman 12mm) that fit snug touching the inner race of the clutch side crank bearing. I heated the socket in the bearing for about five minutes with a propane torch - being very careful to keep stray heat away from the crank seals.

I took the (frozen) crankshaft and used the puller tool to seat the crank in the lefthand/ignition side of the cases. I then set the case on its side and installed the transmission. The crank still fell really cold, so I spent a few minutes reheating the clutch-side crankshaft bearing inner race via the socket and torch.

I then set down a quick bead of kawibond on the (ignition side) case sealing surfaces and started lowering the other case half down (after double and triple checking the alignment dowels were there :lol: ) It got down to a point where there was about a 1/4" gap all the way around the cases all on its own. I was able to use my plastic mallet (normally reserved for stubborn tent stakes) to tap the cases together from the top (clutch side, facing up at me).

Torqued everything together, and it now sits waiting in my basement for the rest of the peripherals to be bolted back on place. :applause:

  • scot_douglas

Posted March 17, 2007 - 08:49 AM

#4

Whoops- just saw you have a 125, not a 100. My mistake. :applause:

  • new_rider3436

Posted March 18, 2007 - 08:07 AM

#5

great info scott douglas, thank you:)
ill print that out to help me along the way

  • new_rider3436

Posted March 20, 2007 - 05:17 PM

#6

:applause: the heating cases and freezing bearings method didn't work for me.....i baked them on 250 but for 10 minutes hmm maybey that could be why...anyways im leaving for florida for vacation tomorrow morning so i can't work on anything for a week....anyways when i get back im going to my grandpa's shop and using his hydrolic press....also i didn't record which way the labels on the right case half's main bearing went(i recorded the left's but not the right's for some reason lol) which way should it face or does it matter? thanks

  • scot_douglas

Posted March 21, 2007 - 04:00 AM

#7

I would highly recommend buying THIS tool to get the crankshaft back in.

  • Polar_Bus

Posted March 23, 2007 - 10:53 AM

#8

alright i have the crankshaft out(used the tusk case splitter:thumbsup: now i need to get the main bearings out....can i do that w/o a press?
thanks


Throw the whole crank assembly in the freezer overnight. Next quickly heat the bearing with propane torch, and slam the stub (hot bearing facing down) of the crank on a wood block, the bearing should slide off. They can be stubborn, so it make take a few tries.





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