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Discussion Starter #1
when i pulled the flywheel on my 650 it was wicked tight it came off with good bang it didn't just slide nicely, now when i tried put it back there is no way to press it on, if i try to push it on with the flywheel bolt the bolt doesn't have the strength to do it, it feels like it wants to break off in the crankshaft, the only way i can do it is to remove the engine and set the whole engine in a press, to get the flywheel on, i can't see how a flywheel can be installed on a 650 with the engine in frame
 

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Discussion Starter #2 (Edited)
when changing a starter clutch how is the flywheel installed without breaking the bolt that hold the flywheel on the crankshaft? what i just reread in manual about installing the flywheel is ridiculous, says to gently push the flywheel on then torque the bolt to spec, how do you gently push something on that's a press fit
 

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Discussion Starter #4 (Edited)
you have a 650, i've never heard of a starter clutch going out on one.the wkb instructions are for the 1100 i would ask at the delphi 650 forum.
believe me i looked at every video i could find even the 1100 video never shows the actual removal and installation of the flywheel every thing else but that, and the 1100 uses a large thick nut not a skinny bolt to push the flywheel on, i was thinking of heating the flywheel in an oven and freezing the shaft to get it to go. i feel sorry for anyone needing to remove the flywheel on 650 for any reason. they would be advised to do it when the engine is out so a press can be used
 

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This may or may not work but I use it on pulley wheels for a large printers which is belt driven. I used a piece of emery cloth to smooth out any burrs both on the shaft and the inside of the pulley. Not sure if it would help here but worth a shot. Also if the shaft and inside of the flywheel are bone dry then its metal against metal and will be harder in my opinion. As with the industrial printer I used a lite mineral oil on the shaft. Maybe something like a little motor oil out there would do the same. Just an idea.

Bill
 

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No way fly wheel should have to be pressed on. Just must be some corrosion or something like Merc said, a burr or nick. And you might try freezing both the shaft and the flywheel to get them to mate up. Heating the flywheel will only make the hole smaller. Freezing it will shrink the hole, as well as the shaft. Good luck.
 

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Discussion Starter #7
you have a 650, i've never heard of a starter clutch going out on one.the wkb instructions are for the 1100 i would ask at the delphi 650 forum.
i did emery the flywheel bore it started to press a little further than before. using the flywheel bolt the bolt started getting a bit to hard to turn again. i don't want to risk that bolt snapping off, tomorrow i'm going to spray the shaft with an air can inverted to freeze it and i'm going heat just the hub portion of the flywheel with a propane torch, i was thinking of putting the flywheel in the oven at 250 but then i changed my mind because i didn't think getting the magnets that hot was good idea, i'm afraid to use emery on the shaft because if i go to far i wouldn't want the assembly loosening when the engine gets hot
 

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Check the following as it should slide on with ease

1) check to make sure there is nothing under the cog to make it stick out more and create a tight fit
2) make sure the cog itself is not damaged, or the space for the cog on the flywheel is smooth an straight
3) check the shaft to make sure it didn't spread out when you used the puller to remove it, I have read its best to keep the nut on when removing the flywheel as it can split the shaft. It may have spread the end of the shaft

good luck
 

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Discussion Starter #10
No way fly wheel should have to be pressed on. Just must be some corrosion or something like Merc said, a burr or nick. And you might try freezing both the shaft and the flywheel to get them to mate up. Heating the flywheel will only make the hole smaller. Freezing it will shrink the hole, as well as the shaft. Good luck.
the 650 requires a 3 eared puller with 3 long bolts screwed into the 3 removed starter clutch bolts as per the manual, so yeah i would say it's definitely pressed on, also heat never shrinks metal it only expands metal, how can there be corrosion when whole assembly is bathed in engine oil, why would i want shrink the flywheel hole when it's too small to begin with
 

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Discussion Starter #11
Check the following as it should slide on with ease

1) check to make sure there is nothing under the cog to make it stick out more and create a tight fit
2) make sure the cog itself is not damaged, or the space for the cog on the flywheel is smooth an straight
3) check the shaft to make sure it didn't spread out when you used the puller to remove it, I have read its best to keep the nut on when removing the flywheel as it can split the shaft. It may have spread the end of the shaft

good luck
there no cogs on my flywheel and when i pulled it i left the center bolt screwed in about half way and pushed off it, the shaft is tapered the narrow end being where the center bolt is, the tough part is the last 1/2 inch where the press fit happens, some guys are saying flywheels aren't pressed, if a 3 jawed puller is required per the manual it's definitely pressed, mine popped pretty good when it released and took a lot of pressure on puller bolt to get it to let go
 

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Discussion Starter #12
i reread your first post.a tapered shaft is not a pressed fit.it only goes on so far.until it makes contact make sure its clean no burrs to interfear and torque the bolt.
a tapered shaft isn't a press fit? hummm what does a press fit shaft look like
 

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Typically a pressed fit requires being pressed on the entire way and not having a taper at the beginning. I haven't had a 650 flywheel off so I'm not much help. But with some lube, a cold shaft and warm pulley should get u damn close. Differnet application but same idea, i put pressed wheel bearings in at home all the time like that. Used to put a few timing chain pulleys on like that in cars, heat the pulley a bit hit the shaft with some freon and slip it on. Ofcourse u are not alloud to vent ac refrigerant ....i just say whoops so it makes it an accident, lol.
 

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Discussion Starter #14
finally got a callback from my friend that worked at a yamaha dealership he told me they hump the whole engine onto a hydraulic press to press the flywheel back on and they are exceptionally tight, when i told him about freezing the shaft he said go for it, it just might work, i wish i knew that a press was needed when i had the engine out i would have pressed it when the case was split and the only weight would have been 1/2 the case and the weight of the flywheel, i'm definitely going remember this episode
 

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Discussion Starter #15 (Edited)
Typically a pressed fit requires being pressed on the entire way and not having a taper at the beginning. I haven't had a 650 flywheel off so I'm not much help. But with some lube, a cold shaft and warm pulley should get u damn close. Differnet application but same idea, i put pressed wheel bearings in at home all the time like that. Used to put a few timing chain pulleys on like that in cars, heat the pulley a bit hit the shaft with some freon and slip it on. Ofcourse u are not alloud to vent ac refrigerant ....i just say whoops so it makes it an accident, lol.
i thought about using 134a refrigerant but i hoping a can of compressed air inverted will get cold enough, i bought 2 cans in case one isn't enough, the 650 rotor is the same idea as a harmonic balancer just a heck of lot tighter harmonic balancers are around a 1to2 press where this rotor seems closer to a 5 to 10 press each number equates to 1,000 pounds of pressure, not only is the shaft tapered but the flywheel hole is tapered the same just a few thousands less, it slides up the taper ok until it hits the shoulder at the last 1/2 inch of the shaft where interference fit starts happening
 

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What a great idea........ Make it so you have to pull the engine too install the flywheel and while we're at it........ let's make them remove the exhaust to change the oil!

Good luck with your attempt. I hope it works, but don't get your hopes too high.
 

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Like i say, if engineers had to fix things they would be designed very differntly. Lol
 

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the 650 requires a 3 eared puller with 3 long bolts screwed into the 3 removed starter clutch bolts as per the manual, so yeah i would say it's definitely pressed on, also heat never shrinks metal it only expands metal, how can there be corrosion when whole assembly is bathed in engine oil, why would i want shrink the flywheel hole when it's too small to begin with
I do apologize. I meant to say that the flywheel hole will expand, or get larger. You are right, metal expands when heated, and shrinks when cooled. And when parts are under pressure, and heated, they will eventually gaul, or stick together. There many forms of corrosion that can occur. Even in an oil bath.
 

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Discussion Starter #19
took a few days but yamaha finally emailed me on how they install the flywheel, they put the crankshaft through the left half of the crankcase and press the flywheel, doing it like that is easy because the whole unit only weighs about 25 lbs
 

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Like i say, if engineers had to fix things they would be designed very differntly. Lol
Don't know if anyone works on a road crew, but I run a road milling machine, converted to a surface miner. YOU talk about a pain in the but to work on. It is a huge machine, but they packed as much junk in it as they could. Oh by the way its German made, nuff said LOL!
 
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