Topic: CB650 Splitting Cases ..... Rotor Removal????

[CBJoe]

I'm having problem splitting the cases on my '80 CB650C and before I break something, I figured i'd ask.

Do you have to remove the rotor to split the cases on a CB650??  None of my manuals mention it but I read a comment from

http://www.myhonda650.com/cb650project.htm  that says that it's a must.

thanks... Joe

[CBJoe]

Thanks for the confirmation.

Murphy's law has struck again, in that now I cant get the $#@* rotor off 

The rear axle threads in fine, but with the motor out and on the work bench I cant seem to get enough leverage to break the rotor free from the shaft.

I got angry at the motor, so I decided to drink some beer and tackle it tomorrow. 

later... Joe

[paulages]

sorry, but i gotta disagree. you don't have to remove the rotor to split the cases, though it's much easier to do so before pulling the engine unless you have compressed air and an impact wrench. the crank seals at both ends of the case on the 550/650, and the seals can bind to the case surprisingly well. if you're sure you have every bolt removed, tap around lightly with a rubber mallet or deadblow. if it still won't come, knock upwards on the rotor a little bit with the mallet.

[InaneCathode]

I've removed a few rotors in my day, it seems the key to getting them off is to get good even pressure with a puller all the way around and straight. Then give the puller a good few smacks. You also can smack around the rotor and on the puller arms.

[cb650]

You dont need to split the cases.  I had one be verry stubborn striped the threads in the rotor not the axle. used a puller and still had to use a little heat.




                      Terry

[CBJoe]

Thanks for the info.  I think things are being complicated by the fact that the PO brush painted the motor with a really thick coat of paint.  I'm going to work at it with a wire brush to ensure that the upper/lower cases aren't being sealed together with paint.

If I don't have an impact wrench and the engine is on the bench, what is the best method to holding the crank in place so that i can put some force into threading the rotor puller/rear axle?

thanks... joe

[CBJoe]

Paul.... Are you sure that the rotor doesn't need removed??  After scrapping and brushing the seams, I got the cases to split, but I cant get them to fully separate where the rotor is   

I would remove the rotor, but with the motor on the bench and stripped down as much as it is, I cant figure out how to keep the crank from spinning.  Strap wrench??

thanks... Joe

[754]

The stock tool for the 750 is put on by hand then struck to loosen.

If you use a tool that looks like a bolt simply hold the rotor and give the wrench a whack with a soft hammer or 2x4, then strike to tool to remove.

An axle may fit, but it is not made to do that job, but people keep on using them...

[paulages]

I have one sitting on my garage floor that seems to be stuck on the rotor. it has come apart everywhere else. I'm sue it's the rotor binding mine up.

i could really be remembering wrong, as i've only split the cases on a run 650 engine once, but when mocking up the 718 i assembled and disassembled plenty of times with the rotor always attached to the crank. done several 550s though, and they all were the same: it feels like there's something binding at the crank, but it's just the seal sticking. do you have the engine upside-down?

[CBJoe]

Yep... I've got it upsidown.  I'm convinced at this point that its the rotor holding it on.  It seems that the cases are slightly inset into the backside of the rotor. I'm going to bolt them back together and take the engine to a friend that has an air impact wrench. 

Thanks for all the help... I didn't intend to start another "how do i remove the rotor" thread 

I just cant believe that got myself to stop prying at the cases .... I usually go to far and break things 

cheers.... Joe

[purf_man]

on my 550 I used a strap wrench (nylon type) and on a wild whim the bolt from a harbor freight power steering puller (same thread as a axle bolt or a purpose built puller and just as checp but comes with other goodies)  I greased up the tip of the bolt to overcome friction better and crank and it just "popped" loose.  it is a taper fit so should just let go all at once and fall out.

even with the cases protruding into the backside of the rotor I would think you could at least get them loose.

[CBJoe]

Thanks purf_man... i'll check that out at harbor freight next time i'm there. 

Then end goal is to split the cases for a rebuild, i just hadn't intended to pull the rotor so i was caught unawares.  I think the tool gods are telling me to buy a strap wrench so I must heed their word   

Cheers... Joe

[CBJoe]

on my 550 I used a strap wrench (nylon type) and on a wild whim the bolt from a harbor freight power steering puller (same thread as a axle bolt or a purpose built puller and just as checp but comes with other goodies)  I greased up the tip of the bolt to overcome friction better and crank and it just "popped" loose.  it is a taper fit so should just let go all at once and fall out.

even with the cases protruding into the backside of the rotor I would think you could at least get them loose.

Wohoo     +1 on the strap wrench.

I got a cheep strap wrench from the auto store and used it in combination with the rear axle. It worked great.  I even popped the rotors off my other two parts engines.  Took less that 2 minutes for all three. 

Once the rotor was removed, the cases pulled right apart.  Either the rotor was causing the problem or while screwing with the rotor I fixed whatever the snag was. So now its time to start making a list of things to buy from honda.

Cheers.... Joe