hours to rebuild bottom end?

wanted to know a rough estimate(hours) for a complete bottom end rebuild including new cases,crank assem all the bearings etc. thanks!

Most rule of thumb for people is every 4 top ends they will replace the bottom also.

Some will believe this is overkill.

But! when you replace your top end measure all clearances for rod play etc. keep a booklet with all the clearances you get and you will know how fast its wearing out.

I think I would go more by service specs than hours. Everyone runs different mix ratios, changes oil at different times and riding style. The service limits are in the service manual and when your in replacing the crank you can go over all the bearings at the same time to make sure they will go another round.

I may be wrong but I think he wants to know how long it takes to replace the parts he mentioned, not when you should replace them.

correct how much time does it take to put new parts in new cases and then put the cases together...

:lol: well it took me about a day to put my 01 back together. That was also changing out a few bearings and cleaning all the parts up. This was also my first time in the bottom end of a dirt bike. When I say a day thats like 6 hours or so depends on how much cleaning and prep work has been done before you start.

well i have new cases all the new bearings for the cases new crank and all the seals for the cases and its already split....just needs new parts put in new cases...reason i ask is the shop wants to charge me 8.25 hrs.I can do the clutch and the side covers not to sure on pressing the crank in is all..i figured 8.25 hrs for assembly of a completely brand new bottom end was alot.

correct how much time does it take to put new parts in new cases and then put the cases together...
New parts in new cases isn't a rebuild, that's building a new engine from scratch.

If you know what you are doing and have the neccessary tools you can do a two-stroke bottom-end in a couple of hours. These engines are not very complicated.

1998 kx 250 what special tools do i need? i've only done top ends so this would be my first bottom...im pretty good with my hands and mind lolol just kinda could i say timid about it lol

8.25 hours is too many hours to be charged by a professional.

Give yourself a whole weekend, AFTER you get the right tools. If you have all those bearings to install in case halves, you need some sort of press. Beating on it with a hammer and socket won't cut it.

I don't see it mentioned, so I will throw it in. Do you own a service manual?? I saw you were asking if any special tools were needed. If you don't have a service manual, then I don't think that a bottom end is the best thing to be working on.

yes i always pick up a manuel lolol(manual)for the bikes i own...i thought 8 hrs was alot thanks...i watched some good videos on you tube of bottom end rebuilds...you can't do the (put the bearing in the freezer heat up the case( a lil) to the other bearings in the case besides the main bearings? also, where would one get a press for this kind of job?thanks for the info

For what the shop will charge you to put it together, you can go out buy the proper tools to do it and have money in your pocket. I think the big one that helps is having some type of press for the bearings. I just used a wrench and some shim on the crank, like what has been mentioned hear before to make sure the new crank did not bend on install. Worked like a charm. It also helps on install of the bearings to throw them in the freezer for a few hours. They will slip in with little to no effort and goes together real nice.

I would invest in the crank puller/installer and the clutch basket holding tool made by Tusk. They both work really well and you can get both of these for $75. That's about what the dealership is gonna charge you for one hour of labor.

Check the FAQ stickey. I did that including taking the pics in about 2 hours but as Chokey will tell you I didn't clean things well, lol.


kewl guys thanx! looks like i pop my bottom end cherry(so to speak) on this kx. Ill get the tools from tusk i need...do i need the kawwy crank jig?

looks like with the tusk installer i dont need the kawwy jig

... where would one get a press for this kind of job?

Where in Michigan are you? If you're at all near the D you can use the press in my garage.

Im about 2 hrs or less from the D(i play at motor city casino now and again)If you have any experience I would gladley pay you and learn.Mark

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