KJWaters217 Posted August 23, 2009 Report Posted August 23, 2009 I have a 96 motor with a broken upper crankcase that i want to replace. Can i replace just the upper case or do i need to find a whole new set? I wouldnt imagine that there would be fitup issues with mix and matching but wanted to ask first. Quote
mopar1rules Posted August 23, 2009 Report Posted August 23, 2009 i believe you need to get a whole new or used crankcase, as the cases are line bored i believe. not a good idea to use the top half of "X-guys" crankcase, w/the bottom half of "Y-guys" crankcase. someone, please correct me if i'm wrong. Quote
KJWaters217 Posted August 23, 2009 Author Report Posted August 23, 2009 Thanks. I was hoping to find a cost conservative way around the issue but i think i am just going to have to find a new set of cases. I thought about just living with the broken ones but i want to do it right the first time that way i dont have any regrets with the finished product Quote
fastbanshee8 Posted August 23, 2009 Report Posted August 23, 2009 If the damage isn't really bad, there are places that can weld them. Then you can use a die grinder on the welds, to clean them up. Quote
Onesickcrewcab Posted August 23, 2009 Report Posted August 23, 2009 If you look on the back of a set of cases. They are actually marked with engravings on the top and bottom halves. The numbers should match. The cases are machined as one. So if you miss match cases they could actually be off enough to create problems. Quote
KJWaters217 Posted August 23, 2009 Author Report Posted August 23, 2009 This is my first picture upload so we'll see if this works...here is my case. Do you think this is beyond repair? Quote
Larry's Shee Posted August 23, 2009 Report Posted August 23, 2009 Don't look to bad. I'd get it welded if you have the chunk that came out. I'd take clutch arm and seal out because of heat. Get it welded both sides, grind/sand down top side. Should be golden. Quote
locogato11283 Posted August 23, 2009 Report Posted August 23, 2009 whats wrong with it? just the little piece missing? mines been like that for 2 years now with no issues. Quote
spurdy Posted August 23, 2009 Report Posted August 23, 2009 Yeah, what's wrong with it? Does it leak? Is it cracked through? If it's just missing the piece from the chain break I would square it up with a die grinder and paint away! I have 2 sets of cases like that. One has been running on my 4 mil for 2 seasons. I have another motor I am putting together for a friend just like it. No worries here. SP Quote
KJWaters217 Posted August 23, 2009 Author Report Posted August 23, 2009 Thanks for your advice guys. It doesnt leak or anything its just purely cosmetic. I dont have the chunk that came out. I'll prolly just square it out like spurdy said and call it a day. Why do Banshees have such a problem with kicking their chain off and breaking the cases? And is their anything to do to help prevent it? Quote
spurdy Posted August 23, 2009 Report Posted August 23, 2009 Thanks for your advice guys. It doesnt leak or anything its just purely cosmetic. I dont have the chunk that came out. I'll prolly just square it out like spurdy said and call it a day. Why do Banshees have such a problem with kicking their chain off and breaking the cases? And is their anything to do to help prevent it? Mostly this is due to poor maintenance. Chain too loose, loose axle nut, worn sprockets, engine seizure, etc. A case saver is the way to go. It mounts around the primary drive sprocket and helps to protect your case if the chain comes off or breaks. I run the TM Design but there are several out there. I think the TM Design is best because it is supported by tabs that butt up against the cases itself for support while others are just bolted on and all the stress is absorbed by the M3 bolts that hold it in place. SP Quote
bansheesandrider Posted August 23, 2009 Report Posted August 23, 2009 (edited) Yamaha only sells them as a set, what's that tell you. After they are cast and initial machining is done they are bolted together and the crank and trans. shaft holes are line bored to their final dimension. So in every set the parting line is slightly different. Some guys mix and match cases and it works OK, but I wouldn't. Banshees dont throw chains if the chain and sprockets are in good shape, all the rollers and guides are in place and the chain is properly adjusted. Replace the stupid roller around the swingarm with a slider from Cascade, TM Designworks, or UPP. Also, make sure your axle bearings are good, the only chain I ever had come off was from bad axle bearings. I would just clean up the breakage and run it. Edited August 23, 2009 by bansheesandrider Quote
KJWaters217 Posted August 23, 2009 Author Report Posted August 23, 2009 Since its already broke is it worth buying the case saver. The break is already close to the clutch arm so if it happened again it could screw that up right? Quote
spurdy Posted August 23, 2009 Report Posted August 23, 2009 Since its already broke is it worth buying the case saver. The break is already close to the clutch arm so if it happened again it could screw that up right? Absolutely! If the chain breaks again it could bust a hole in the case and then you are buying a new set of cases! I broke a tooth off of a gear one time high in 3rd and locked the tranny up and snapped the chain. That case already had been bitten once before I got it. The case saver prevented further damage. The TM Design is more expensive then the others but I think in this case you get what you pay for. SP Quote
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