440 Output bearing, used engine, compression?

Hey all. I have a problem with my 82 440 D.

I recently bought it and it had high idle troubles so I cleaned the carbs and replaced the boots and the bike runs excellent now.

But about 3 weeks had a situation where the front drive sprocket nut came loose and the sprocket ended up off the shaft splines and riding on the threads. After this the seal started pouring oil. So I replaced the seal and put the sprocket back with a new nut, lock washer and some loctite for good measure. All was well for about 2 weeks.

Then I started noticing a ticking noise and since it has progressively gotten worse. It turned into a light grinding noise on deceleration. I pulled the clutch cover thinking i may have a loose bolt or uneven tightening on the clutch. The noise had me thinking it could be that, but no. And nothing I do with the clutch lever takes the noise away.

So I got to thinking if the oil seal got damaged from that sprocket failure, it must also have damaged the output shaft bearing. So I rode it to test it for a week and sure enough the noise is worse and I am pretty sure I've eliminated it to that.

My trouble is, even having a service manual to guide me, it seems like a treacherous job to replace the bearing. But I may be able to hold my nose and tough it out. Then I checked my options and the reputable local shop quoted me about $400 + parts...if I bring in just the engine. I figure if I pull the engine I might as well take a stab at cracking the case and replacing the bearing myself.

Then I got to looking at eBay for used engines and I have found a couple for right around $500, which would make life easier, but also cost money, all the while bugging me that I would be ditching my original 4,500 mile engine for an unknown. One from an 81, with 120/150 cold compression with oil in the cylinders and 90 without and an 82 engine with 14,000 miles that I haven't gotten a test result for yet.

Would it be best just to have the shop fix it? I hate to ditch my low mileage engine or mess it up by trying to fix it myself. Especially getting into removing the stator and oil drive gear and getting into the transmission or is it really that tough? Would I need a puller for that particular bearing or does it slide right off? Would i have to remove the stator etc or can i just remove each side cover and crack the bottom while leaving everything in place? Would getting a used engine be a good way to go? If so what compression numbers would help me choose a good engine?

Any help is appreciated. I'm kind of stuck in a rut on what to do. Spend $500 either way or fix it myself if possible. Thanks all. I value your opinions.

Just figured I would throw this out there. I think you can use the bottom end of a 400 motor as well. Its a modification I have thought about making because the 400 bottoms have a kickstart. In my opinion a parts bike would be cheaper than ebaying a motor. I have picked up all my twin kzs under $400 and they were in good shape. If your inclined you could probably part out and make some money back on the rest you don't keep for parts. Just my 2c

Fix what you have. That way you know what you have.
You might regret the lock tight thou.


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