Topic: Cylinder assembly questions

[gary p.]

Time to tackle a long postponed assembly of my cb500 engine.  The cylinders are bored .5mm over.  Do I need different gaskets because the bore is larger or are standard 500 gaskets for the cylinders okay?   Should I use new cylinder studs or are the original studs okay?  (When replacing the head on my MGB it was advised to use new studs.) I haven’t seen either question discussed in any manual I’ve found. 

[MauiK3]

The gasket should be fine.
The studs should be fine as long as you can see that they weren't damaged.
Use a torque wrench.

[calj737]

Any time you replace the cylinders, you will need to re-torque the head studs after running the engine. So the question I would ask you is: “With everything you’ve done/you’re doing, would you kick yourself later if a head stud failed?

Replace them now while they’re very accessible. All too often they can strip or shear off later. Prevent problems later by doing things like this now before you reassemble the motor.

[Don R]

 I like to use a good inch pounds torque wrench on the smaller studs and bolts. I have a couple and often compare them to check accuracy. I wouldn't be afraid to re-use the studs. I have not seen aftermarket heavy duty cb500 studs anyway.

[Little_Phil]

Any time you replace the cylinders, you will need to re-torque the head studs after running the engine.

Really! This is a 500, but that would be even more interesting on the 750.
The studs will be likely be fine.

[calj737]

I like to use a good inch pounds torque wrench on the smaller studs and bolts. I have a couple and often compare them to check accuracy. I wouldn't be afraid to re-use the studs. I have not seen aftermarket heavy duty cb500 studs anyway.

http://www.dynoman.net/engine/studs.html

The stud has a specific torque value, then the nuts a different torque value. Both are less than 20ft/#, but the 50 year old cast aluminum case is the weak link. Plus, any erosion of the stud over time.

[calj737]

Any time you replace the cylinders, you will need to re-torque the head studs after running the engine.

Really! This is a 500, but that would be even more interesting on the 750.
The studs will be likely be fine.

Yes, really. Any time the head is replaced and the gaskets are swapped, a re-torque is appropriate.

They may “likely” be fine. But why not swap them now while they’re completely accessible? Save the hassle later.

[Don R]

 CMSNL has studs for $8 each, Honda does not. 

[gary p.]

Thanks gents.  It seems prudent to put in fresh studs now while I can.  Thinking back, my son had the bike while in college and may have had the head off back then.  So I’m not sure how many times they may have been loosened and re-torqued and if they were torqued correctly.  When in doubt…
When I drove to Buffalo to pick him up, the bike was in their apartment living room, on the third floor!   

[scottly]

Should I use new cylinder studs or are the original studs okay? 

As Maui said, the stock studs are fine, as long as they are not damaged. In fact, most failures with the stock studs and the threads in the block are the results of removing the studs: leave them be. Also, it is a myth that a head needs to be re-torqued after running it. I've never done it, and the factory certainly didn't.

[Don R]

 I've removed factory studs and they don't like to come out. I'd let the sleeping dog lie.

[gary p.]

Again, thanks for the advice.  I asked because part of me though it would be a good idea to put in new studs.  That likely comes from my experience with the MGB head replacement where replacing the studs is a recommended practice.  The difference, however, is the MGB has a CI block and the CB Aluminum.  As some have pointed out, the risk of doing harm is greater.  So I will go forward with the original studs, which all look to be straight and undamaged   
I greatly appreciate the help and wealth of information available here. 

[MauiK3]

I do a next day torque check just to be sure I didn't miss any and to see if the gaskets settled. Sometimes I get a bit of movement on a few.
Gives peace of mind.

[HondaMan]

When I do these, I look closely at the 2 rear inner studs closely: they seem to be the ones that deteriorate (corrosion) the most often. Once in a while (rarely) I have seen the next 2 (between cylinders 1-2 and 3-4, at the back) in poor shape. Moisture can get trapped in them if the bike spent lots of time in car washes or humid (Florida) places. But, removing them in the 500/550 is much more tricky than in the 750: the cases are not as dense a metal as in the 750, and when corrosion does happen it seems to REALLY grab the studs. This usually happens from the crankcase end because they are thru-holes (i.e., "wet" oil left inside a long time, or water vapor condensation from sitting 20-30 years with old oil) of the stud, so they end up getting bored out and Helicoiled then. Not much fun.

[Don R]

 Rock on brother!