Newbie Engine Rebuild Questions (Part II)

[sultan]

'83 GS650GLD, 22K miles. This is a follow-up to:
http://www.thegsresources.com/_forum/showthread.php?t=124056

I have replacement piston rings, a flex hone tool, and some other gaskets and things on order. Once I get these, I believe I have everything I need to proceed except a bit more knowledge on what I'm doing. If anyone can answer the questions below, it would be appreciated.

It seems that there are flexhones for different materials. My cylinder bore is 62mm, so a 2.5" hone would be just right, correct? But I'm seeing "Aluminum Oxide" and "Silicon Carbide" hones. I assume that I need the Silicon Carbide hone? Or does it really matter?

Valves:
I searched the forums and found this post, among others:
http://www.thegsresources.com/_forum/showthread.php?t=84587
It seems the forum user camps are split on valve lapping. My manual says not to lap as well, but it also mentions using prussian blue to check valve seating. Is it worth it to do this? ie, is it accurate enough to tell me if I have a problem, at which point I should lap, or should I just lap anyway? (I'm referring to hand-lapping/resurfacing, not re-cutting the seat or anything.)

In some of the posts I saw recommendations in regards to replacing the "valve seal". I'm assuming this is the oil seal? About as round as a dime with a cup-like metal outer housing, rubber inside gasket, and a small spring around the top?

Gaskets:
Is it better to use the gaskets "naked"/as-is, or add some high-temp gasket compound to them to get a better seal? (I had an oil leak from one of the engine gaskets previously, thus my paranoia.)

From other posts, some people recommended putting silicone on the half-moon inserts in the cam cover. Should this actually be silicone, or high-temp gasket compound, or does it matter?

In cleaning things up, i went ahead and took off the pistons. The manual recommended replacing the piston pin retaining rings. Is this really necessary? (I didn't order these, and would have to wait to get them.)

FYI, the kerosene flush of the crankcase seemed to go pretty well. I got some grit/sand in the catch pan. I've got all the gasket seats cleaned up and now I'm just waiting on parts. Thank you to all those that replied to my previous post. I greatly appreciate the help.

 

[hampshirehog]

I would always lap the valves in - fine paste only, not grinding with the coarse stuff.

You've identified the valve stem oil seals correctly - don't be too rough when taking the old ones off as you can snap the valve guide. Put a touch of Molyslip in the valve guides when you rebuild.

I always smear a touch of grease on my gaskets - makes a better seal and stops them sticking too much if you ever have to remove them again. Caution when doing this on the base gasket; it can take a bit of fiddling to drop the cylinders on and if the gasket is smeared in grease it could catch bits of grit on it which will mess with your seal. Don't grease your head gasket, or smear any sealant or anything else on it.

I suspect that silicon will be the best sealant around the half moons and others will have their favourite brands. Having said that, when I haven't had any in the garage I've used other types of gasket sealant and I've never had a leak.

Definitely replace those piston pin retaining rings ( gudgeon pin C clips in the UK). Once you've pinged them out they will have lost some of their tension and there is an increased risk of them coming out with the motor spinning. I've only not replaced these once - and guess what happened? A few pennies for the clips or a lot of pennies for a whole load of new internals.

Someone else will have to answer the Q about the hones - I don't know if there is any difference but then I didn't know there were 2 types.

 

[Suzuki_Don]

Forget the hones. Just take your cylinders to a machine shop and they will do it for a few bucks. My machine shop did mine at no cost, cos I was getting the cylinder head done there as well. Valve seats recut.

 

[waterman]

I am in same boat as you except maybe a step ahead. I have just honed cylinders, and have valves out of head. I will probably lap valves, need to get a tool (or use my sons toothbrush with the suction cup end!). As for flexhone, I used a 180 silicon carbide? It was this one

http://cgi.ebay.com/ebaymotors/2-1-...oryZ6755QQihZ024QQitemZ370046022282QQtcZphoto

This same seller has two 240 grit flexhones, but they didn't sound like the right tool for the job. I did mine in about 5 minutes or less and look great. Check youtube for a video. Real easy.

If you can find a machine shop to do it reasonable, great. I was quoted $90 which I thought was outrageous.

Valve seals are pretty easy, just turn and pull out old, set new ones on guide and gently tap into position with 10mm socket and soft hammer. Use a little assembly lube on valve stems.

Have to agree, put nothing but grease on gaskets. Head gasket is dry. I have had good luck with yamabond for half moon and cases. Pay attention to torque values for head and go easy on cam shaft hold down bolts. Tighten them down evenly, you don't want to break one or strip it out after all this work. Somewhere I read about using a clamp on cam to hold down while tightening holders. Good luck.

 

[Suzuki_Don]

Pay attention to torque values for head and go easy on cam shaft hold down bolts. Tighten them down evenly, you don't want to break one or strip it out after all this work. Somewhere I read about using a clamp on cam to hold down while tightening holders. Good luck.[/quote]

That would have been in the Suzuki Factory Manual.