Remove valve guides from 650?

larrycavan wrote:

wireman wrote:

steell wrote:

I don't know about motorcycle heads, but of all (100's) of automotive heads that I have taken to machine shops to have the valves ground, not one ever lapped the valves.
Every single one said it was a waste of time to lap valves after grinding, but I never believed that so I did a test. Two identical Chevy 350's, same miles same chassis, etc, sent both sets of heads out to have the valves ground, got the heads back and I lapped the valves in one set while leaving the other set alone, installed new identical cams in both vehicles and bolted everything back together.
End result was the vehicle that I had lapped the valves in had noticeably more power.

but they were ground 1st,lapping the valves will not substitute for a good valve job if the valves and seats are already borderline in my book;)

Exactly. Lapping is the last step in the valve job process and NOT a substitute for properly cut seats and refaced or new valves. Different people have different theories on how to do a valve job.

If you've got a Serdi machine then you cut the angles all at once. I dont' have one so I use a Black & Decker seat grinder for the 45 so they're good and straight and then hand cut the inside and outside angles with hand cutters.

If you take your head to an automotive shop to have a valve job done, don't have them assemble it. Instead bring it home and thouroughly clean it. I've seen heads come back from shops full of grit and assembled.

IMO, it's good practice to have motorcycle people work on your motorcycle engine parts because they generally have the proper attitude to do the work correctly. Some automotive places treat your parts like they're going on a tractor.

I'm also not a big fan of bronze valve guides. I prefer the iron guides.

ive been arguing with people about iron and bronze guides in automotive applications for years i was always taught to use iron guides over bronze most people seem to lean the other way.pros and cons of each?

Ok, just to be clear, I was not saying that lapping will work instead of grinding (actually cutting), I was saying to make sure they are lapped after cutting. My buddy the motorcycle machinist is the only machinist I have ever met that agrees with me that valves need to be lapped after cutting new seats, I am sure that there are others, but I have not met them

My life as a mechanic started at age eight, straddling a six cylinder flathead Studebaker motor lapping the valves

I guess it kind of stuck with me

It certainly was a long strange journey today trying to find a shop that could give me a straight answer on doing the valve seats and refacing the valves.

Stop #1: Local Kaw dealer. Guys in the shop stated they did their own such work, but really didn't want to talk to me. Only told me the hourly labor rate and could not provide even a general estimate. Seems they don't do too much valve job work if they can't quote a min and max price.

Stop #2: Another local bike shop. Same thing. Told me the hourly rate.

Stop #3: Local custom bike shop. THIS guy was knowledgeable. Gave me a couple of references.

Stop #4: Bike salvage yard the guy at Stop #3 sent me to. He referred me to someone about 30 miles outside of town that I left a message for this afternoon.


UPDATE: 4:10 pm EDT: The referral at Stop #4 paid off! Machinist has a shop in the general area who is experienced with bike valve jobs. Can do the valve job and hone the cylinders for about $125, including lapping. THAT's what I thought I should find, someone with valve job experience who can give firm quotes.

Post edited by: drayman86, at: 2007/02/19 16:09

wireman wrote:

larrycavan wrote:

wireman wrote:

steell wrote:

I don't know about motorcycle heads, but of all (100's) of automotive heads that I have taken to machine shops to have the valves ground, not one ever lapped the valves.
Every single one said it was a waste of time to lap valves after grinding, but I never believed that so I did a test. Two identical Chevy 350's, same miles same chassis, etc, sent both sets of heads out to have the valves ground, got the heads back and I lapped the valves in one set while leaving the other set alone, installed new identical cams in both vehicles and bolted everything back together.
End result was the vehicle that I had lapped the valves in had noticeably more power.

but they were ground 1st,lapping the valves will not substitute for a good valve job if the valves and seats are already borderline in my book;)

Exactly. Lapping is the last step in the valve job process and NOT a substitute for properly cut seats and refaced or new valves. Different people have different theories on how to do a valve job.

If you've got a Serdi machine then you cut the angles all at once. I dont' have one so I use a Black & Decker seat grinder for the 45 so they're good and straight and then hand cut the inside and outside angles with hand cutters.

If you take your head to an automotive shop to have a valve job done, don't have them assemble it. Instead bring it home and thouroughly clean it. I've seen heads come back from shops full of grit and assembled.

IMO, it's good practice to have motorcycle people work on your motorcycle engine parts because they generally have the proper attitude to do the work correctly. Some automotive places treat your parts like they're going on a tractor.

I'm also not a big fan of bronze valve guides. I prefer the iron guides.

ive been arguing with people about iron and bronze guides in automotive applications for years i was always taught to use iron guides over bronze most people seem to lean the other way.pros and cons of each?

Wireman...you and I should open a shop together because we are so on the same page with most things it blow my mind!

I don't like bronze guides for 2 reasons.

1. IMO, they tighten up too much when they get hot.
2. Iron holds up better.

I have seen bronze guides sieze valve when clearanced to dimensions that iron guides can run and not sieze valves. That's not been just my expereince either. I've received the same feed back from other engine builders. I suppose someone would argue contrary but what I see with my eyes...I believe.

drayman86 wrote:

It certainly was a long strange journey today trying to find a shop that could give me a straight answer on doing the valve seats and refacing the valves.

Stop #1: Local Kaw dealer. Guys in the shop stated they did their own such work, but really didn't want to talk to me. Only told me the hourly labor rate and could not provide even a general estimate. Seems they don't do too much valve job work if they can't quote a min and max price.

Stop #2: Another local bike shop. Same thing. Told me the hourly rate.

Stop #3: Local custom bike shop. THIS guy was knowledgeable. Gave me a couple of references.

Stop #4: Bike salvage yard the guy at Stop #3 sent me to. He referred me to someone about 30 miles outside of town that I left a message for this afternoon.


UPDATE: 4:10 pm EDT: The referral at Stop #4 paid off! Machinist has a shop in the general area who is experienced with bike valve jobs. Can do the valve job and hone the cylinders for about $125, including lapping. THAT's what I thought I should find, someone with valve job experience who can give firm quotes.<br><br>Post edited by: drayman86, at: 2007/02/19 16:09

When you get the head back, turn out the shop lights, put your eye right up to the rubber intake boot and wick a flashlight around the valve while looking into the port runner. You should not see any light.

NOTE: If your head is not assembled, a good seating valve will have a nice ring to it. That's how I know the seat is straight when I'm cutting them, before I check them with light.

Support the head off the work bench or let it hang over the end of the bench. With the chamber facing up, push the valve open with your finger from the bucket bore side, lift it about .5" and let it drop to the seat. You'll hear the ring I'm talking about. It's very noticable with 2V heads. The intakes more than the exhausts.

Thanks larrycavan.

Should I bead-blast the valves and the head prior to machining? Thinking it would be a good idea to give the shop a nice clean head and valves.

drayman86 wrote:

Thanks larrycavan.

Should I bead-blast the valves and the head prior to machining? Thinking it would be a good idea to give the shop a nice clean head and valves.

I'll bet they'd really appreciate it.

drayman86 wrote:

It certainly was a long strange journey today trying to find a shop that could give me a straight answer on doing the valve seats and refacing the valves.

Stop #1: Local Kaw dealer. Guys in the shop stated they did their own such work, but really didn't want to talk to me. Only told me the hourly labor rate and could not provide even a general estimate. Seems they don't do too much valve job work if they can't quote a min and max price.

Stop #2: Another local bike shop. Same thing. Told me the hourly rate.

Stop #3: Local custom bike shop. THIS guy was knowledgeable. Gave me a couple of references.

Stop #4: Bike salvage yard the guy at Stop #3 sent me to. He referred me to someone about 30 miles outside of town that I left a message for this afternoon.


UPDATE: 4:10 pm EDT: The referral at Stop #4 paid off! Machinist has a shop in the general area who is experienced with bike valve jobs. Can do the valve job and hone the cylinders for about $125, including lapping. THAT's what I thought I should find, someone with valve job experience who can give firm quotes.<br><br>Post edited by: drayman86, at: 2007/02/19 16:09

Or you could just look it up on some neat website;
www.aperaceparts.com/headwork.html

Jay

APE Jay wrote:

drayman86 wrote:

It certainly was a long strange journey today trying to find a shop that could give me a straight answer on doing the valve seats and refacing the valves.

Stop #1: Local Kaw dealer. Guys in the shop stated they did their own such work, but really didn't want to talk to me. Only told me the hourly labor rate and could not provide even a general estimate. Seems they don't do too much valve job work if they can't quote a min and max price.

Stop #2: Another local bike shop. Same thing. Told me the hourly rate.

Stop #3: Local custom bike shop. THIS guy was knowledgeable. Gave me a couple of references.

Stop #4: Bike salvage yard the guy at Stop #3 sent me to. He referred me to someone about 30 miles outside of town that I left a message for this afternoon.


UPDATE: 4:10 pm EDT: The referral at Stop #4 paid off! Machinist has a shop in the general area who is experienced with bike valve jobs. Can do the valve job and hone the cylinders for about $125, including lapping. THAT's what I thought I should find, someone with valve job experience who can give firm quotes.<br><br>Post edited by: drayman86, at: 2007/02/19 16:09

Or you could just look it up on some neat website;
www.aperaceparts.com/headwork.html

Jay