Engine Rebuild: Valvetrain Components Available?

[Bill__Woods]

As with most thing hes says, i agree with TopCat.

I am an auto mechanic, every cyclinder head I pull goes straight to the machine shop. I have them milled flat, checked for cracks, and cleaned/ They almost Never replace valves that are not Burnt or Bent.
Valves are made to be ground again if needed. You just have to make Certain that after grinding them that you measure the Margin.
Here is a tip.
take valve grindiing compond, but it on the valve & seat. Insert valve into guide. Attach a pice of vacuum lhose to a drill bit, and instet valve stem into vacuum hose. Pull toward you and Slowly rotate the drill. This will remove small pits, scrathed & carbon from the valve & seat. Clean all parts with brake cleaner. Turn head upside down, and SLam the valve into the seat Hard a few times with your index finger. Remove the valve and you should be able to see a small ring on the valve when it contacted the seat. This shows where they meet. That way you can check your margin. I have done this a few times while doing head gasket on jap cars with high mileage. Works like a charm That is my CBMMA advice.
My professinal advice is take the head to a Machine Shop, and let the pros do it. If you take it to an automotive machine shop, the price should be much better than most motorcycle machists. They both do the same job, but the auto shop will win on price. From a machists standpoint, they don't care what the head came off of. All they need is the specs, tolerances, and the valve stem seals. If you do a overhaul you do not need a machinst most likely. if you are going to Rebuild it, you will Need a machinst. Installing ring & lapping valves is NOT a Engine Rebuild.
you may not Need a rebuild though, which is the great part!
Hope this helps you, go visit your machinist.

[Shuriken]

Thanks for the advice, guys.

I'm not crazy, just haven't had enough time lately. So I haven't pulled the head just yet. I've just been kind of thinking of the worst so I would have the parts if necessary.

I'm not sure who I can take the head to around here. The last job I had at the machine shop was a bore and hone on a single cylinder 2-stroke dirtbike. I installed a new piston and had to have the cylinder bored. They charged me $68 dollars. I had expected to pay $40. I will have to ask around because I will probably have to have the valve seats worked on and a bore/hone. $68 bucks a hole is a lot to pay for a bore/hone. Maybe not, I'm no machinist. But it all adds up.

I hope to get into the head sometime next week. I'll be keeping everyone informed the whole time. I have a digital camera and will be asking advice!

Thanks guys.
Ben

[TopCatGr58]

Thanks Bill,

Ben, almost 3 years ago when I did my Big Bore, I had a racing bike machine shop do my boring, and it was $40.00 a hole. I live in Va. but the southeast where the cost of living isn't as high as in the D.C. /MD area! With inflation and labor costs, I would expect it to be a little bit higher, but not $68.00??

And IIRC, Geezer said that the machine shop must have tapered the cylinders to make it easier for me to put the pistons back in with only using my fingers to compress the rings instead a fancy ring compressor!? I could have sworn that the cylinder bottoms were tapered when I pulled them out before the bore!?!?

Good luck, we'll be here when you need us!!!

T.C.

[Shuriken]

Yeah, $68 bucks. I'm sure you guys can feel my pain!

I think there is another way. I will ask the Yamaha shop to give me a price quote and hold them to it. I think when they take parts to the local machine shop it's cheaper.

I think I heard one of the shops tell me once that the machine shop charges more for customers and less for the bike shop. I will have to double check on that but there is no way I can afford to pay $68 x 4. It would be more cost effective to ship it somewhere. Especially if the valve seats need work.

Ben

[Shuriken]

I just received the valves I ordered.

Just in case I find something bad when I get into the top end I ordered 4 intake and 4 exhaust valves. They are aftermarket Vesrah valves. They came in the packages and look like old stock.

Does anyone have any advice for the newbie when inspecting the cylinder head? I am particularly intersted in knowing your tips on how to check the valve seats, existing valves, carbon cleaning, etc.

I hope when I get into the head and cyls I could get away with a bore/hone and a simple valve job.

Ben

[MartyA]

Where'd you get the Vesrah valves?

I took my head off last summer. It was the timing chain, though, not a valve issue. I never touched the valves, just cleaned the surfaces for the new gasket, and chipped a lot of carbon off the head and pistons. Be very careful if you chip the carbon off, don't use a sharp edge, use something like a small dull screw driver. Don't make any sharp gouges in the aluminum, this could later cause pre-ignition.
I actually dampened small pieces of rag with ammonia, then packed them into each chamber, covered it with a flat piece of wood overnight and them wiped most of the carbon out the next day. Ammonia will soften the carbon. Buy the $0.89 bottle of household ammonia from the grocery store, and do it OUTSIDE. Oven cleaner will work but I don't know what additives are in them and what they might do to aluminum.
For the pistons, bring each up to TDC, carefully scrape - try not to 'chip' as flying parts of hard carbon could get into the oil pathways - the carbon off, again don't gouge. If you are not doing the rings, then be careful not to disturb the carbon ring around the top of the cylinder.

Check the head mating surfaces with a straight edge. I had full compressions when I did my cleaning so I just put the new head gasket on and bolted the head back on. Everything worked fine for me.

[Shuriken]

Thanks for the replies.

It looks like the Vesrah valves I got are years old - like they have been sitting on the shelf for a long time. I don't think it hurt to buy them. I tried Dennis Kirk and they didn't stock them anymore. I tried other sources and they were out and couldn't get more or were more expensive.

The guys that hooked me up are at:
http://www.cyclewareables.com/

Not a pretty site but I think they can get a lot of things.

Ben