Bottom Cylinder Stuck...like REALLY stuck.

[Red Fthr]

After ruining every pair of shoes and pants I own via leaky oil I decided to replace all the gaskets in my engine. I'm following the manual and was cruising through the procedure until I got to the bottom cylinder. It seems to be stuck...like really stuck...like cemented on kinda stuck. I've dumped PB Blaster all down in it as well as break cleaner in hopes of loosening any possible adhesives. No luck. I've broken two screw drivers trying to pry it off and chipped a fin or two trying to knock it loose. I've also put a 2x4 under the #13 screw hole (the last screw to unscrew in the manual on the back side where the cam chain tensor would be) and whacked it with a hammer. It split the 2x4 and knocked the engine off it's resting place and the cylinder didn't budge.

Can someone lay some wisdom on me? Any other chemical reactions I can try or any physics tricks I don't know about?

oh, and yes, every nut and bolt that can be undone is.

 

[AlphaDogChoppers]

I'd bet a dollar to donuts that you still have a fastener that you missed somewhere holding it on.

 

[Red Fthr]

@Alphadog I hope you're not a bettin man because I didn't. I just went back to the garage though and tried out the whole heat thing and that with some light tapping around the seam with a flat head got it loose .

While I have your attention though, the other bike I'm playing with, the one with the hanging idle, is still having the same issues after doing everything everyone suggested. I've heard F-ed up valves will cause similar problems, is that true? I know from reading these threads you're quite the valve guy. Also should I lap my valves while I have my top end apart, everyone says I should but I recall you saying it isn't really necessary unless they've been cut or something like that? I already have them out and ready to go if I need to though.

Good talking to you. You're a life/ bike saver.

 

[CafeDawg]

Some things I did to free up mine.... ATF/Acetone mixture, suspend motor with straps run under the jugs using the weight of motor to do the work, heat, Air with a large socket plugging the cylinder. I ended up having to beat on the socket and ruin the piston to free mine up. Process can take weeks.
http://forums.sohc4.net/index.php?topic=106235.0

Respect
CD

 

[Sonreir]

Over time, the cylinder jugs can get "welded" to the engine case due to the heat cycling of the engine. The base gasket sort of turns into a very stuff glue.
I've found the best way to remove the cylinder when this occurs is to apply more heat.

If you live by yourself (or don't mind asking for forgiveness) you put the engine into your oven at 300°F for an hour and tap on the jugs with a mallet (avoid hitting the fins, they break easily).

If that's not an option, a heat gun or blow torch around the back or front of the seam for several minutes should generate the amount of heat necessary. Again, follow this up with some tapping of the mallet while everything is still hot.

Once you have just a little gap showing, you should be able to GENTLY pry is the rest of the way apart.

 

[Sonreir]

I'd bet a dollar to donuts that you still have a fastener that you missed somewhere holding it on.

Pretty sure the jugs are only held in place by the head studs on a CB500.

 

[AlphaDogChoppers]

Won't hurt to do a very light lap job. Do it no more than necessary. The biggest mistake novice wrenchers do is to "lap them real gud." The service manual says what the contact area between valve and seat should be. Example: the cx500 I am doing right now is 1.1 mm to 1.3 mm with a service limit of 2 mm. After you lap it a little, wipe clean and look at how much "satin" area you have on the valve. That is the area that the valve grinding compound was cutting. Measure the width of that band. Use a dry erase marker to ink the seat, then push the valve into it. It will show you if you are getting good contact all around.

Be VERY careful that you don't get any valve grinding compound in the valve guides. After you are done, wash very thoroughly with detergent and water. Not with solvent. Valve grinding compound is in an aqueous slurry. Even the tiniest bit of valve grinding compound in an engine is very, very bad. It can embed itself in parts and cause damage over a very long time.

I generally advocate not disturbing the valves if they are sealing OK. Not everyone agrees with that philosophy, and those who disagree with me could be right. <G> You already have them out. Lap them a little.

Lapping has a technique. Here is an excellent video on proper technique. Be sure to buy the lapping tool. I bought a small one this week at NAPA for only $7. Makes the job much easier.

http://youtu.be/fhXsH12Rg6s

 

[Red Fthr]

Thanks for the advice guys, top end work will be much easier in the future.

@alphadog I'll give it a go and thanks for the heads up, I could see myself making sure they're lapped "real good." Can't wait to put this baby back together and hopefully there will be no more oil on the ground every time I ride it.