the bearing replacement is the easy part. the crank journal being worn down/damaged/scored/ out of round and the rod being out of round is the real problem. the crankshaft can be machined, the rods can be refitted, and over sized bearings can be installed. the cost to rebuild the engine, with all the necessary machine work (the cylinder walls and rings will also be addressed) far exceeds the cost of a used motor, not to mention the down time.

demon

 

I usually check on E Bay for parts. My bike is down too. Ran 87 octane for a test ride with wide open throttle on the freeway, during an Exit to my place the bike ran rough got it home with a backfire and poping noise. I think i burned an exhaust valve or broke a valve spring. Now thinking rebuild or just buy a used motorcycle with low miles. I have an 89 Hurricane 600cc. My problem is the cali model for the Cylinder Head hard to find parts to rebuild and some parts are no longer available. You should have no problem with your F2 plenty of parts on E Bay.

 

^^^ i do have a 93 cylindar head, valves are fine, 32xxx miles..

 

You're down below the level I play, Chris. I don't mess below the top-end/head gasket.
So I don't have much to offer in the way of advice to you.

I just wanted to remind the other folks (who actually can make intelligent comments)
giving you advice, no disrespect intended...This guy is a serious machinist, that's not
an issue for him. If he's looking to do a complete tear-down, he's got the chops.

If he's looking to re-build not replace, all he needs advice on is the steps not the alternatives.
Don't worry, he's not digging a hole without a ladder. Check out his build
thread and you'll see where he's coming from. (Sorry to talk about you in third person, lol)

And now back to your regularly-scheduled program...

Ern

 

Chris thanks you for the plug dude! =)
i have had the engine completely apart down to the crankshaft before and that is part of why i am leaning towards getting a new engine. this one should have been perfect. i measured and checked and plasti-gauges everything before buying new bearings...

but the engine was severely abused apparently. i found a guy with an low mileage engine he bought as a spare for his that has been sitting in his garage and now he just needs to get it out of the way. he was $300 for it and will meet me halfway to pick it up.

My biggest concern is not the ability to check everything or machine things down, but even if i do that and get all new bearings i may pu tit back together only to have it crap out again. better to start fresh.

i really do appreciate your help and concern and it is a good topic, i would love to have any other option, so if you have one please throw it out.

 

hey man, that's a really nice price on a motor too if it runs as well as the seller says

first though, you, me, and everyone else on here knows nothing yet about what's ACTUALLY going on in there as far as how extensive the damage is. you won't until you tear it down. and besides, there's no harm IN tearing it down considering right now, it's scrap as is.

if you tear it down, realize that the crank is done, a rod is done, or whatever - you can still sell the rest of the bad motor and buy a good motor.

or, you could realize that with a little bit of polishing, the crank can come back, you might find a CHEAP set of rods on ebay (maybe you won't need them at all), the piston/cyl wall gap might be within spec...

my point is - don't make any assumptions or decisions now. you're obviously not going to be riding it tomorrow, and it doesn't cost a thing to tear it down and see what's what. so do that first.

you'll always be able to find an f2 motor in the future... so don't stress if you miss out on this one (although like i said, that's a bitchin' good price).

 

you make a very good point, and i am most certainly going to pull the engine apart. however, i am on a self-imposed time crunch to sell the bike due some deal-making with my wife. so i get a new motor, paint it, put it in, and sell the bike, then i can sell the engine as whole or parts (depending on the damage)

but then i can investigate when i am not so manically busy and pressed for time.

these are a couple a videos of the engine, let me know what you think:

http://s2.photobucket.com/albums/y10...DSCN1638-1.mp4
http://s2.photobucket.com/albums/y10...DSCN1639-1.mp4
http://s2.photobucket.com/albums/y10...DSCN1640-1.mp4

 

That engine sounds good. I don't like that he took it up to redline with so little warm up time, but if that isn't done on a regular basis it's not a big deal. Proper oil and filter maintenance is important and what I would be concerned about.

 

Buy the motor!!! Lol then you get 2 motors like I had and get to turn 1 motor into a super Godzilla mechasarus motor that shoots mofoin lazers!!!

 

that motor sounds pretty nice man. for $300, you can't really go wrong.