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Valve job advice please

  • Thread starter Thread starter snyderman
  • Start date Start date
S

snyderman

Guest
I pulled my valves with the PVC spring compressor (aweaome tool!). It looks like the PO was not into shimming.

View attachment 13620.

After this pic was taken, I used some brake cleaner and a green nylon scrubbie to clean it up. It worked on the "bowl", but I cant get to the aluminum on on the exhaust seats. Any suggestions for getting this clean? Also, I am thinking about my next step. Is there anything I can do myself as far as a valve job is concerned? I have a pic of the valves, but it appears that one file upload a day is my limit. I will post a pic of the valves asap.

thanks!
 
That head needs some serious cleaning before you can tell what you have. To be honest, it's not looking good from what that first photo shows.

When faced with similar issues on a few different bike rebuilds I was able to find decent used parts off ebay for cheaper than it would have cost to have them rebuilt. In fact, it was WAY cheaper.

Good luck
 
Thanks, although that's not what I was hoping to hear! I wish I had a pic of it after I cleaned it up, it really desn't look bad. there is still carbon in the exhaust valve seats and down by the valve guides, but the rest looks good. It looks like all the aluminun is there, if I could get the carbon off. Is there a good way to remove that carbon?
 
snyderman said:
Thanks, although that's not what I was hoping to hear! I wish I had a pic of it after I cleaned it up, it really desn't look bad. there is still carbon in the exhaust valve seats and down by the valve guides, but the rest looks good. It looks like all the aluminun is there, if I could get the carbon off. Is there a good way to remove that carbon?
Click to expand...

Soak the parts in Seafoam. Works very well. Also you can chuck them up in a drill motor and use an abrasive on faces and stems. Stay away from seats with this method. Ray
 
I've been there, done that on worse. Bead blasting was how I did it. Followed by sandpaper drum rolls in a Dremel, followed by conventional valve lapping.

This particular head is off a Honda SL125 and the motor is back in service today. :)

Kirk

03-ChamberDirty.jpg


01-IntakeDirty.jpg


02-ExhaustDirty.jpg



06-Chamberclean.jpg


04-IntakeClean.jpg


05-ExhaustClean.jpg


Copyof008.jpg


09-FinalIntakework.jpg


Copyof006-2.jpg
 
The important part is the valve seat, which is of a hardened material. If it needs to be replaced you would be better served just finding another one.
If you can clean them up, as well as the valves, then you can most likely lap them in and be good to go. The lapping material and the lapping tool are fairly inexpensive.
 
As koolaid kid says, the seat is the critical thing, and the valve guide but lets leave that out for now. In particular, the seat where the valve contacts. There should not be any pitting in the seat, or the valve, where the two parts contact each other. If there is, you need to have the valve seats and valves machined - commonly denoted as performing a "valve job". Minor pitting can be removed by lapping, but not deep pits. The problem comes in regarding cost. A proper "valve job" will cost you a pretty goodly bit of money, way more than buying a clean used head.

As for how to clean that mess, I suggest soaking in carb dip. If you set the head in a large tub and keep it wet with carb dip for a day or so most of that grudge will hose off.
 
As an example, I had the head on my GPz redone by a professional race motor shop. They did a great job, check the valve guides, shimmed it, checked out valve heights and verified they would not hit my Wiseco pistons, etc. etc. They also replaced all my valves. But it set me back ~$500 to get it done.
Unless you are building a race motor, your better choice would be to find a replacement if the seats or valves are damaged.
 
snyderman said:
I have a pic of the valves, but it appears that one file upload a day is my limit. I will post a pic of the valves asap.
Click to expand...
The trick is to not "upload it". Not sure where you are uploading it to, but put all the photes you want on PhotoBucket, then post the IMG links for the pictures in your message, like kirkn did. You can post up to 10 pictures per message that way. If you have more than 10, just start another message in the same thread.

.
 
Thanks for all the advice. I will clean things up the best I can and post pics. Is bead blasting something that I can have done (bring my head somewhere)?

Ryonker - I live in Stacy, about 15 miles north of Forest Lake.
 
I cleaned up my valve seats with a Dremel and a brass wire brush. seemed to remove the black and leave the silver. There is some pitting. #1 cylinder is the worst, and they get better from 2-4. 4 looks great. Any idea why that would be?






Can these be lapped? The #1 exhaust valve itself looks great.
 
You can try lapping and then see how it looks. Many people tend to ignore some random pitting but personally, I like to see clean metal.
 
I picked up a suction cup lapping tool and a package of VersaChem metal grinding compound. It has a coarse and a fine grit. I thought I would start on the worst seat with the fine just to see what I get, then use the coarse only if I need to. This is my first time lapping. Any advice?
 
Don't know if the fine will remove enough to get you there, but you won't get into any trouble that way either. Go for it and see what you have. Should clean up enough to run again I'll bet. Good luck with it. Ray
 
what grit is the fine I used 600 grit on mine and it worked ok it was a little slow but you wont take too much off. Look on you tube for some tips.
 
I took my first shot at lapping the worst seat (#1 exhaust) and got a nice silver ring on the valve, but the seat still had pits. I put the springs back in and poured some brake cleaner (the only liquid I had handy) in and it leaked right through. I am starting to think that I need the seats re-cut. If I do this, do I need to have the valve re-ground? what else needs to be done? the guides seem good and tight. If I can lap the intakes, can I have just the exhaust seats cut? I talked to a machine shop but they wanted to do a full valve job. They charge $162 for a standard 8 valve job.I need to know what my options are, and at what point it would make more sense to get a different head. I guess I am worried about buying a used head with bad seats as well. any advice on how to shop would also be appreciated!
 
If the pits are at all deep, it will take forever to lap them out by hand. (Remember you're not cutting the pits, you're cutting everything except the pits to get down evenly to the deepest part of the pits.) I would deliver the head and valves to the shop so that they can check for leakage before delivering it back to you - for that money, there should be none. I would also check references on the shop unless you already know and trust them for quality work.
 
Thanks, I am going to bring the head and valves in and let them go at it. I talked to them on the phone and they tell me that that price includes bead blasting, cutting seats, grinding valves, lapping and reassembly. The only thing not included in the price is for seals, which will be replaced ($3.50 ea.). I will ask for references. Anything else I shouild be asking, or aware of?
 
I strongly recommend you find a motorcycle specific machine shop or head guy. Car guys may be okay but I wouldn't trust them with my bike unless you find someone that has a personal reference to the quality of their work.
 
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