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One of our forum members asked me this question, and since it's similar to something I hope to be doing later this year, I thought I'd ask the question here.

He has two motors.
1. Has damaged valves because of mistake made when changing timing chain tensioner, bent valves etc.
2. Second motor is fine but damaged in lowside, suffers from the damage to lower casings which is so common.

Question.
1. Is it possible to swap bottom ends.
Rip the clutch and gearbox out, spin motor upside down, pull the bottom casing and fit the good one.
2. Rather swap heads.

I would rather just swap the heads but is it possible to swap bottom casings also if he wanted to do that.
New crank bearing shells? How would you do it, Noel.. Ed.. Balz.

Thanks for your time guys.
 

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Old Wing Nut
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Big issue here is the cases are line bored and a mismatched bottom case has possibility the bearing bores will not be concentric and possibly/probably not the same ID.
Not recommended, which is exactly why you can't buy one half of a crankcase for any modern plain bearing crank engine.
Bottom line, swap the heads.....
 

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Same with Laverda Jota engines, Line bored and the chances of matching two halves of the crankcase are remote.

I have a F4 1000R cylinder head spare if of use ?

joe
 

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Dons, thank you for the help. I was hoping to see if anyone knew of problems associated with trying to do that job. Luckily you guys did and now I won't break in to the motor for no reason. I picked up the engine on ebay and it showed damage in the pictures but didn't show that it was leaking oil. When I replaced the cam chain tensioner, that didn't go in smoothly I took the bike out for a ride and lost the valves on cylinder 1 and 3 on the intake side. Bike sat while I recovered from shoulder surgery. I ordered the one from ebay, noticed it was leaking on both sides. On the left side where the F4 cover is the location where a bolt goes is broken off, so it doesn't seal well. The right side has a similar issue. Other than that the motor was from an 08 low miles and runs great. Again thank you for the advice and time saved!

JCC
 

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Donsy;
the cases are as Ed said line bored as a pair..... you can't replace one half.......that isn't saying it can't work

just the probability is about zero......

most engine main bearing saddles are marked AFTER boring with a size code for fitting main bearings from a chart
 

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JCC, Donsy......

me I'd weld or epoxy the damaged cases as long as it didn't get into the oil gallery.....

then I'd split the cases and weld it......:naughty:

:drummer:
 
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