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Thread: Mid-section noise

  1. #16

    Re: Mid-section noise

    So I have decided to go ahead and split the powerhead.


    The powerhead is now removed from the midsection and I have discovered that the crankshaft seal is leaking oil mixture + badly rusted.


    Let hope it is only 1 bottom bearing and couple of seals and gaskets!

    Attachment 120181
    Attachment 120182

  2. #17

    Re: Mid-section noise

    Make sure u use at lease good but cheap torque wrenches when u reassemble because a correctly torqued bolt is at 90% of its breaking strength so if u use shit ebay tools it may snap the bolts or even under torque them

    Make sure u blow out or pick out all old silicone from blind holes as it can blow the blind section off the back of the blind threaded bokt hole when u reassemble

  3. #18

    Re: Mid-section noise

    Thanks mate - I have torque wrench from supercheap auto that I have been using for years now

  4. #19

    Re: Mid-section noise

    Yeah they are petty good not cheap by any means at almost 100 bucks each my 1/4" and 1/2" are from super cheap

    "

  5. #20

    Re: Mid-section noise

    Finally managed to get some time to split the head.

    Here is the result:


    Bottom bearing is clearly shut.

    Any thoughts

  6. #21

    Re: Mid-section noise

    Wash the whole thing in a 2 stroke petrol mix using a new clean paint brush to clean the bearings than place your finger on top of the bearing and roll it slowly to see if u feel any notchyness or grinding or any side or up and down movement

    That top bearing looks like a needle roller bearing it should slide up and off there will be a bushing pressed on the shaft or a inner bearing race u need to inspect that for wear and colour

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  7. #22

    Re: Mid-section noise

    Do you think by cleaning first, it could resolve the noise?

  8. #23

    Re: Mid-section noise

    Cleaning the bearings will give a better indication on there condition, u can hold the bearing still and blow thru it with compressed air to clean it u keep repeating this untill your either happy its a clean and reusable bearing or u chuck it in the bin

    To me bearings are a cheap part to replace vs my time in pulling the powerhead apart and reassembling it

    The only bearing and bushing i see costing a bit of money is that top needle roller bearing the one under the flywheel its not usually the bearing that cost the money its the bushing or centre race that cost a lot but usually u can get away with just replacing the bearing

    When u clean the crank grab a cheap plastic tub from bunnings pour $15 worth 9f 2 stroke mix in there put the crank in give it a wash, u can spin the bearings up with compressed air if the bearing is submerged in 2 stroke fuel this is the easiest way of cleaning the bearings

    A loud bearing to spin is often an indication its no good but it may be a faulty indication if the bearing is very clean and dry as its ment to be lubed with 2 stroke mix but it is good to say if any bearing has or had had rust it will without a doubt have pitted the races

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  9. #24

    Re: Mid-section noise

    This is how i clean my 2 stroke cranks notice the bearing wasnt raced with the compressed air out of the fuel mix but this crank needed a rebuild from the salt water that filled the crankcases



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  10. #25

    Re: Mid-section noise

    Awesome! Thanks mate. The top bearing is not cheap! I'd rather clean as much as possible the top bearing and change the bottom one as it is only $40.

    The center bearings seem to be fine. I'll give it a good clean and should be good to go.

    The only problem is that I dont have any press to remove the bottom bearing and to reassemble the bearing.

    I am thinking of getting a bearing puller for removing and using heat for reassembling.

    Any thoughts?

  11. #26

    Re: Mid-section noise

    Had another look at your crankshaft, getting the bearing off is easy putting the new bearing on is not so easy

    You can use a bearing puller to remove the bearing

    To reinstall the bearing u should use a press but u may be able to get by using a steel pipe and hammer, make sure u take all measurements of where the bearing is located on the crankshaft it has to be prescise in its location u may need to check it with a vernier caliper or valve adjusting tool to check the clearance

    What u dont want to do is moving the bearing back and forth trying to align it...

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  12. #27

    Re: Mid-section noise

    some good insight into this cheers guys

  13. #28

    Re: Mid-section noise

    Quote Originally Posted by Tyfab14 View Post
    Awesome! Thanks mate. The top bearing is not cheap! I'd rather clean as much as possible the top bearing and change the bottom one as it is only $40.

    The center bearings seem to be fine. I'll give it a good clean and should be good to go.

    The only problem is that I dont have any press to remove the bottom bearing and to reassemble the bearing.

    I am thinking of getting a bearing puller for removing and using heat for reassembling.

    Any thoughts?
    with the new bearing, if its a non sealed, you can heat it up with a gas torch. obviously you don't want to heat it till changes colour, but you want it too hot to touch. using leather gloves, slide it on, should go on easy.

  14. #29

    Re: Mid-section noise

    I personally would cold press the bearing even if its the brutal method of using a piece of steel tubing and a hammer

    Heating the bearing may change its temper

    Sent from my SM-G900I using Ausfish mobile app

  15. #30

    Re: Mid-section noise

    Whilst waiting for the parts to come for rebuilding all the bearings, I've come across some rust on top of the 3rd cylinder and some pitting corrosion started to appear on top of the block surface.

    Attachment 120254Attachment 120255


    First, Do I bother honing cylinders (it's on top where the rings don't even go on the rusted surface and have to get additional tools and new OS rings..)
    Second, How can I prevent the pitted corrosion on the block surface? (I sprayed lanox for the time being)

    Cheers!


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