Fullthrottle02 Posted August 23, 2010 Report Share Posted August 23, 2010 I noticed a small leak where the cases meet near the front mount. I will be pulling the motor out this week to fix. My question is can i just flip the motor upside down, remove what needs to be removed in order to split the cases and just pull the boottm case half off? Keep the cylinders, etc. bolted up, the crank and tranny will stay it the top half wont it? I think I have done this once before, but can't remember for sure. Thanks - Quote Link to comment Share on other sites More sharing options...
Larry's Shee Posted August 23, 2010 Report Share Posted August 23, 2010 Yes Quote Link to comment Share on other sites More sharing options...
bbcmudtruck Posted August 23, 2010 Report Share Posted August 23, 2010 Yep, it can get a little tricky putting it back together though. Every time I've done it like that I've had to fight with the transmission lining up correctly putting it back together. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 23, 2010 Report Share Posted August 23, 2010 Yes it can be done. The ONLY time I'd do that is if I were stuck on a trip or at the track and had to get it back together to ride. You're home, make it easy on yourself and split it the normal way. You're only saving a few bucks on gaskets, etc., to do it right. Quote Link to comment Share on other sites More sharing options...
Fullthrottle02 Posted August 23, 2010 Author Report Share Posted August 23, 2010 Yes it can be done. The ONLY time I'd do that is if I were stuck on a trip or at the track and had to get it back together to ride. You're home, make it easy on yourself and split it the normal way. You're only saving a few bucks on gaskets, etc., to do it right. Removing the head and cylinders off is nothing, but if it was all the same whether you remove the top or bottom, I would prefer to remove the one that requires less tear down. But there again, Ryan said it can be a bit tricky putting it together. 6 in one hand 1/2 dozen in the other. Thanks for your guy's input. Quote Link to comment Share on other sites More sharing options...
dajogejr Posted August 23, 2010 Report Share Posted August 23, 2010 Like anything else...disassembly is the easy part. Getting everything to line up (trans, clips, etc.) is a real PITA.... When you're hours from home and/or money is on the line, you gotta do what you gotta do...but the traditional by all means is much easier... Quote Link to comment Share on other sites More sharing options...
NYUK Posted August 23, 2010 Report Share Posted August 23, 2010 take the time to do it right the 1 st time. because you will most definitely make enough time to do it right the 2 nd. Quote Link to comment Share on other sites More sharing options...
RagunCajun Posted August 23, 2010 Report Share Posted August 23, 2010 Getting everything to line up (trans, clips, etc.) is a real PITA.... very true. Last year i did it and the shift forks were in the wrong spot. I didnt think to spin the sprocket over to make sure it spun freely. Well the entire bike was assembled when i figured it out. I called it quits till the next day haha. Quote Link to comment Share on other sites More sharing options...
TIM LUTZ Posted August 24, 2010 Report Share Posted August 24, 2010 First time I split my cases I did it bottoms up. Ran er a little low on trans oil flying across a frozen lake in 6 gear. The thing sounded like an old craftsman drill. Flipped it up side down on the bench and replaced the whole transmission without even taking the head off. Try doing that with YZ,CR,KX or RM. Remember this motor started life on the street and the cases split like a street bike. Just be as careful as you would doing the EZ way and you should be fine. Quote Link to comment Share on other sites More sharing options...
J-Madd Posted August 24, 2010 Report Share Posted August 24, 2010 I'd say it's a no brainer to not take the top end off. Sit the trans in the bottom case half and hold the crank while lower the top down onto the bottom half upon reassembly. Done it a dozen times. BUT - what kind of leak are you talking about? It's not leaking between the case halves, that's just about impossible for a leak to develop there as long as yamabond was used during assembly. You sure it's not oil from the exhaust - leaking around the pipe o-ring? I'd wanna be 100% sure that the cases were the problem before even pulling the motor. Quote Link to comment Share on other sites More sharing options...
Fullthrottle02 Posted August 24, 2010 Author Report Share Posted August 24, 2010 I'd say it's a no brainer to not take the top end off. Sit the trans in the bottom case half and hold the crank while lower the top down onto the bottom half upon reassembly. Done it a dozen times. BUT - what kind of leak are you talking about? It's not leaking between the case halves, that's just about impossible for a leak to develop there as long as yamabond was used during assembly. You sure it's not oil from the exhaust - leaking around the pipe o-ring? I'd wanna be 100% sure that the cases were the problem before even pulling the motor. 100% sure its coming from the case halves. I noticed some fluid leaking, and my first thought was exhaust, but after further examination you can see it bubbling out in a very very small spot when it was hot. Its been fine since July09 when it was rebuilt. I did just change domes from 21's to 18's. Quote Link to comment Share on other sites More sharing options...
S-oregon Posted August 25, 2010 Report Share Posted August 25, 2010 100% sure its coming from the case halves. I noticed some fluid leaking, and my first thought was exhaust, but after further examination you can see it bubbling out in a very very small spot when it was hot. Its been fine since July09 when it was rebuilt. I did just change domes from 21's to 18's. I've split the cases both ways and I have to say, if you are just working on the bottom end, turning the case upside down is the easiest. A little trick is to tightly zip tie each end of the crank up and around the same side spark plug first, before splitting the cases. This will keep the crank in the cylinders nice and tight so you don't have to worry about it coming out. When you put it back together just set the tranny in the lower case, pick up the upper case, which will have the cylinder and crank secured and set in down in the lower case. This way you don't have to worry about lining up the tranny and shift forks. Real easy to do. Quote Link to comment Share on other sites More sharing options...
spurdy Posted August 26, 2010 Report Share Posted August 26, 2010 Removing the head and cylinders off is nothing, but if it was all the same whether you remove the top or bottom, I would prefer to remove the one that requires less tear down. But there again, Ryan said it can be a bit tricky putting it together. 6 in one hand 1/2 dozen in the other. Thanks for your guy's input. I've done it twice recently when my override shelled. Ryan and Tyler helped with the first one. The only tricky part was the tranny. An extra set of hands and it isn't bad at all. On the second go around I found an air leak under one of the cylinders. Had to take the jugs off anyway. Even doing that, I didn't take the head off. Just removed the 8 nuts and took off the head and both cylinders. Going back together was a little tricky but my 10 year old held the rings while I slid the jugs on, we did it first try (some of the guys on here know my boy, he's gonna be a hell of a mechanic! Lol!). SP Quote Link to comment Share on other sites More sharing options...
J-Madd Posted August 27, 2010 Report Share Posted August 27, 2010 100% sure its coming from the case halves. I noticed some fluid leaking, and my first thought was exhaust, but after further examination you can see it bubbling out in a very very small spot when it was hot. Its been fine since July09 when it was rebuilt. I did just change domes from 21's to 18's. You could just epoxy the outside of the case if you know exactly where the crack is.. Quote Link to comment Share on other sites More sharing options...
Fullthrottle02 Posted August 27, 2010 Author Report Share Posted August 27, 2010 You could just epoxy the outside of the case if you know exactly where the crack is.. Na, it too easy just to split them. S-oregon and your first recommendation worked like a charm. Flipped it over and took the bottom off, transfered the tranny into the bottom half, secured the crank in the top half, and set the top half down. Piece of cake. Will test tonight Quote Link to comment Share on other sites More sharing options...
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