Triad Posted yesterday at 08:12 PM Report Share Posted yesterday at 08:12 PM (edited) Hello guys, last year I've got a 1973 Explorer with a semi-seized engine. Managed to find another one that should be in working conditions but the owner doesn't know which model it's from. I tried putting the engine in, it looks the same when it comes to frame brackets but it doesn't fit... it's like it's slightly thicker than the stock one where the engine meets the frame in the swingarm/filter area. Also noticed the right side sprocket cover is different (longer)... any idea? Is it better to slightly file the engine bracket or the frame? Edited 23 hours ago by Triad added pictures Quote Link to comment Share on other sites More sharing options...
konrad Posted 9 hours ago Report Share Posted 9 hours ago (edited) 16 hours ago, Triad said: Is it better to slightly file the engine bracket or the frame? Those engine brackets already look pretty insubstantial by modern standards. I would not want to thin them. How much material do you think needs to be removed? Make some measurements. P.S. It may be preferable to heat and bend the frame mounting points. In general, I try not to make modifications that can't readily be undone. Edited 8 hours ago by konrad Quote Link to comment Share on other sites More sharing options...
Triad Posted 9 hours ago Author Report Share Posted 9 hours ago Yeah, I plan to measure the old engine "brackets" with a caliper and compare them to the ones of the "new" engine. I didn't pay attention to it before buying, silly me, but from the shape of the right side cover I'd say it comes from the enduro version... who knows what other differences there are. The carb inlet is bigger, can only hope the exhaust flange is the same. Quote Link to comment Share on other sites More sharing options...
konrad Posted 8 hours ago Report Share Posted 8 hours ago What is "semi-seized" on your old engine? Can you make one good engine out of old and new parts? Quote Link to comment Share on other sites More sharing options...
Triad Posted 8 hours ago Author Report Share Posted 8 hours ago Well, the original Explorer engine turns but it takes a lot of force... probably a seized bearing on the bottom? Also not sure the Motoplat works, as it requires 500rpm to make a spark and there's no way to make it turn that fast as is. It's been outside for years, I think, so rust might be the issue... and the reason for being there might have been a broken Motoplat unit (no spark)? No way to know for sure. The "new" engine was stored on a shelf with the inlet taped, and the guy told me it was bought from a reputable seller, so IN THEORY it should run. I plan to make the engine brackets slightly thinner as they're massive, while the frame brackets are already thin. I'll have to measure them, but as I said I'm now worried other parts might be different and I might find out the hard way. Quote Link to comment Share on other sites More sharing options...
woody Posted 58 minutes ago Report Share Posted 58 minutes ago The centre cases are all the same casting so are interchangeable. The reason the ignition cover might look different is because the rear most part sometimes gets cut off or modified, either to stop a build up of mud or they simply get broken by derailed chains The replacement engine is an enduro engine, the Explorer is a trials engine. The enduro motor will have a different state of tune/porting and different gear ratios. They also use an expansion chamber motocross type exhaust although your Exporer exhaust should still fit into the cylinder. They use a 32mm carb as they're basically a race engine It's not an uncommon problem to find a different engine won't slide into the rear frame mounts. You might find that the mounting brackets have been squashed inwards slightly with repeated tightening over the years. You can try puting a piece of solid bar against the inside face of one and putting a solid bar through the hole in the other and tapping outwards, then repeat on the other side to try and open them out a bit. Or just take a bit off the engine to enable it to slide in Quote Link to comment Share on other sites More sharing options...
Triad Posted 51 minutes ago Author Report Share Posted 51 minutes ago Thanks a lot! Yeah, I tried to "open" the mounting brackets a bit by hammering a round piece in but still won't go in freely. I think I'll remove some material from the casing as the frame side brackets aren't exactly ultra-thick... So I'll need a different intake manifold? Might probably find a silicone one on Amazon, maybe... but my priority is to see if it has spark and runs. If it works I'll gladly put some work into it, but due to my previous bad luck I'm a bit skeptical Quote Link to comment Share on other sites More sharing options...
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