I going to be splitting the crankcase on my 91' lt250r pretty soon. Probably in a week and a half when I get back from wyoming snowmobiling. I was wondering if anyone had any tips for splitting them to make it a little easier for me. I have a manual. I will be replacing the crank bearings, seals, and anything else that needs to be replace when I open it up. I hope just those bearings and seals though. It already has a new crank which was put in about a year or so ago.

Does anyone know of any tips or things I should check for when I open It up?

Chuck

 

I just did mine a few months ago for the first time. It's really easy if you take your time. When splitting the cases just make sure you don't try to pry the two halve apart. My came apart really easy, but if yours don't you can give it a few light taps with a rubber mallet. I would have a good munual when putting it back together, because there are a few parts that may just fall out of place when the cases are split. There is a ton of info on the web you may want to read if this is your first rebuild. Here is one that I used: http://www.off-road.com/atv/2stroke.htm Good luck.....

 

Splitting cases is easy. After you get all of the bolts out of it and are ready to split them, put a flat blade screwdriver between the crank journal and the case. Tap the screwdriver with a hammer. As it starts to split, move the screwdriver backward and put it in the gap that is now between the cases. Open the gap up a little more then move back to the front. Turn the engine on its side. Continue until it is split. Remove the top half then put the screwdriver between the other journal and the other case half. Tap the screwdriver until the crank pulls out.

I have split probably a dozen cases. This is the easiest and best way to do it.

Make sure not to let the case with the tranny on it fall over, otherwise you have to reassemble the tranny.

 

Thanks for all the info. I hope it goes as easy as you guys say it does. I already have everything off but the stator and the gears on the other side of the crank. Are the crank bearings hard to get out? any tips on that? Is there anything else I should check out closer than normal once it is split? thanks for the help.

chuck

 

Sometimes the bearings come out with the crank and sometimes they stay in the cases. If they stay in the cases, you can press them out with a shop press, drive them out with a slide hammer, or knock them out with a hammer. If they stay on the crank, they will usually have to be pressed off or you have to use a bearing seperator.

 

I would be very careful about using a screw driver to split the cases. If you pry juist a little two much you can leave a mark on the cases that can cause an air leak. Also before you put the cases back together make sure that all the old sealer is removed from the case, because your new sealer will not bond well to old sealer.

 

87 is right about being careful. I should have said that it shouldn't have to be forced. You will have to use the hammer at first when the screwdriver is in between the journal and case, but you shouldn't have to use much force when splitting the back part of the case.

Let us know how it goes. I give out a lot of info and never hear back. I like knowing any problems that people run into.

87, does the LT use a gasket between the halves? Some bikes do, but I have never split a later model LT case and I can't remember if my 85 used one or not.
If it doesn't, go to your local dealer and buy a tube of Threebond's gasket sealer or go to a yamaha dealer and buy their Yamabond. It works great for all of those places that need to be sealed but can't use a gasket. Such as rocker covers and case halves.

 

The LT does not use a gasket between the case halves. When using the sealant make sure the halves are really clean and only use a thin coat on both halves. You don't want that stuff dripping into your gears. Any of the sealants Alky mentioned are good, I think I used Hondabond or something like that. Now for the rest of the gaskets you only need to use the paper gaskets. Some people put a sealant on those, but I don't recommend doing that. You don't need it and it's just one more think to muck up your motor. Hope this helps. Alky is right..let us know how it goes. I got a ton of help when I started rebuilding my quad and I always came back and thanked people. There is info in this forum that you will never find in a book!!! I'm kinda a newbie...there are people in here that know it all, so keep asking.

 

I just got back from wyoming today. I will probably do it this week sometime. It was real fun snowmobiling in the mountains. I only bent the a-arms on one side of the sled (02' zr800) a little bit. I'll be replacing them this week too. I hope it goes good when I split it. I will post after I split it.

chuck

 

have fun with it chuck, I just split mine last week and am awaiting parts. If you need seals and gaskets, I suggest ebay, I got a complete gasket set, and seal kit for 58.49 shipped. If ya need any step by step help, email me at Holygoalie13@aol.com .

Dink