Harleydavidson 222 Posted October 27, 2022 (edited) learned i gotta split the cases on my kx250 to replace crank seals was wonderin best way to get them to split got another kx250 engine that threw a rod in 2020 still in the junk pile cause the cases would not split broke 2 pullers on it took it to a shop and then they couldn't was told kx250s are hard to split and technique to get em apart also doing crank bearings while i'm in there i know put the case in the oven and bearing in the feezer to get then in, but what about out, just beat them? EDIT: just noticed should've put this in motorcycles but technically is a quad since the frame Edited October 27, 2022 by Harleydavidson Share this post Link to post Share on other sites
SlammedRanger 1,504 Posted October 28, 2022 I use a case serperation tool like this one. Screws into the holes in the case halves and pushes against the end of the crank. Share this post Link to post Share on other sites
Harleydavidson 222 Posted October 28, 2022 1 hour ago, SlammedRanger said: I use a case serperation tool like this one. Screws into the holes in the case halves and pushes against the end of the crank. I’ll try again that’s one I broke Share this post Link to post Share on other sites
SlammedRanger 1,504 Posted October 28, 2022 22 minutes ago, Harleydavidson said: I’ll try again that’s one I broke You can add alittle heat to the casting around the bearings. But dont go crazy. The cast should expand at a way faster rate than the hardened material the bearings are made of. I would put some pressure on it with the seperator and heat it gently. It will probably start popping and moving little by little. 2 Share this post Link to post Share on other sites
oldmxrider 71 Posted October 29, 2022 On most cases there are hollow steel dowels at the very rear and possibly front, Heat that area with some pressure on the seperator tool and with right side down crack the counter shaft with a plastic dead blow hammer. They all come apart just did a KX250 last week new main bearings and seals and rebuilt the crankshaft with new rod, pin, bearing and spacers! Good Luck ! 3 Share this post Link to post Share on other sites
Harleydavidson 222 Posted October 29, 2022 (edited) About to take the cylinder off and split them wish me luck Edited October 29, 2022 by Harleydavidson Share this post Link to post Share on other sites
Harleydavidson 222 Posted October 29, 2022 (edited) Well after the catastrophe the cylinder was now some idiot put JB WELD on the cases update: it’s only in one little spot so not as bad Edited October 29, 2022 by Harleydavidson Share this post Link to post Share on other sites
Harleydavidson 222 Posted October 29, 2022 (edited) Victory folks I got it apart now I just gotta get the parts ordered Edited October 29, 2022 by Harleydavidson 7 Share this post Link to post Share on other sites
Harleydavidson 222 Posted November 3, 2022 parts came in today got the right side seal and bearing in gotta go pick my left case up from the shop had to get the stator off to get the bearing out and the screws were stuck pretty good in a few days she should be running 1 Share this post Link to post Share on other sites
Harleydavidson 222 Posted November 4, 2022 Can’t get the gears to go onto the end of the crank same gears that came off what happened? Share this post Link to post Share on other sites
oldmxrider 71 Posted November 4, 2022 Should go on with no problem. Sometimes the seal is a bit tight a little lube and a tap or two should do it. Share this post Link to post Share on other sites
Harleydavidson 222 Posted November 4, 2022 Got that stuff back on now the left bearing gets really tight if I put the case back together if I leave probably 4mm of space it’s fine but tighten it the crank barely moves Share this post Link to post Share on other sites
toodeep 1,733 Posted November 4, 2022 4mm is a lot of gap, did you replace/get the correct bearings? If it was 1mm or less I would just say a bearing wasn't completely seated and usually a couple taps on the crankshaft (protecting it of course) will get everything in place and moving freely. That much gap I would double check stuff. Share this post Link to post Share on other sites
oldmxrider 71 Posted November 5, 2022 Is the crankshaft centered in the case ? I take a feeler gauge to both sides and center them. I do have a press. Though as to deep said are You sure the main bearings were completely seated ? Share this post Link to post Share on other sites
Harleydavidson 222 Posted November 11, 2022 Been a hot minute since an update but I figured out why it got tight the right bearing wasn’t seated all the way got it fixed now just gotta wait in parts Share this post Link to post Share on other sites
oldmxrider 71 Posted November 12, 2022 I was just going to ask for an update! Hope it goes well! Share this post Link to post Share on other sites
Harleydavidson 222 Posted November 18, 2022 Got the new parts in and the cases back together it’s late so I’m gonna continue tomorrow Share this post Link to post Share on other sites
Harleydavidson 222 Posted November 19, 2022 On a scale of 1-10 how bad is this it ran fine before but how much longer will it run Share this post Link to post Share on other sites
oldmxrider 71 Posted November 20, 2022 Looks like You have some gouges and worn nikasil on the exhaust port and some aluminum stuck to the nikasil on the intake side. Does not look pretty. What does the piston look like ? Muriatic acid removes aluminum from nikasil plating. Share this post Link to post Share on other sites
shadetree 5,543 Posted November 21, 2022 i'd say its toast, i would not run it. 1 Share this post Link to post Share on other sites
oldmxrider 71 Posted December 2, 2022 What did You end up doing with it? Share this post Link to post Share on other sites
Harleydavidson 222 Posted December 3, 2022 1 hour ago, oldmxrider said: What did You end up doing with it? Bought a new cylinder for $150 haven’t had time to put the engine back in but I got it together 1 Share this post Link to post Share on other sites
