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Kawboy's restoration/conversion of a 1980 KZ13 7 years 3 months ago #15089

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hillsy wrote: Now that you have a lathe, it might be easier to weld / relocate the collet grooves on the valve stems so you can tip them back to spec.

Just a thought - seems to me this would be an easier task than welding / grinding the cams.


Not out of the question but it would require different lock collars and the tipping procees is typically done on not hardened valve stems although capping could be done. The spring pressures will go up substantially and then there could be coil bound issues.
Another possibility could be to have custom valves ground at probably $ 60 a pop. Grinding the cam will accomodate the issue and open up new experimental opportunities. also, there will be no issues with piston valve interferrence. although the deeper sunk in of the valves will have reduced the compression slightly. The whole "experimenting idea provokes all kinds of thoughts.

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Last edit: by Kawboy.

Kawboy's restoration/conversion of a 1980 KZ13 7 years 3 months ago #15095

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Kawboy wrote: The spring pressures will go up substantially and then there could be coil bound issues.


They wont go up if the valve stems go back to the same "original" length - remember the valves have recessed in the seats so the valve stem length has "grown" with wear and the valve spring pressure has reduced.

Ideally new valves and seats would be the fix but replacing the seats is not really a DIY option.

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Kawboy's restoration/conversion of a 1980 KZ13 6 years 5 months ago #17479

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It's been a long time since I posted anything regarding this bike of mine.
A quick recap-
I had a set of camshafts ground and the shop that ground them really bitched them up. Now they're garbage.
I'm now in possession of 6 sets of camshafts and plan on building a camshaft grinder to profile my own.
In the meantime I had a machine shop grind a set of valves and cut the valve seats and after trying to fit them together found either the valves are overground or the seats are cut too deep and even the minimum shim at 2.00mm is too big to get the clearance. So, I've spent countless time and effort trying to get custom valves made to accomodate the head with the overcut seats. Best price I could find was from Ferrea Valves at $65 U.S. a piece. By the time I got them up to Canada we're just shy of $1,000 Canadian for a complete set of 12 valves . Well, that ain't happening. I just ordered a complete set of valves from Germany. God only knows who manufactures them and I swore I wouldn't buy valves unless I knew who made them and what material they were made from. Let's hope I didn't get screwed again !!!
The plan will be to fit the new valves and see where we are at as far as shims go. I do want to grind the cams and then send them out for nitriding. I've formulated a plan to build the camshaft grinder and will start posting as that comes together. Lots of really neat Youtube videos from guys who have built machines to do this. Gave me some really good ideas and I've adapted those ideas into a slight mod to this small metal lathe. Looking forward to getting at this. Unfortunately, a lot of my time is devoted to "other : things and leaves me short of "Me Time"

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Kawboy's restoration/conversion of a 1980 KZ13 6 years 5 months ago #17480

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The valves, the rings.. haha Actually nothing to laugh about. These are the basic but crucial components, and its like hitting a wall. That set of valves you mentioned would cost more than what I paid for the whole bike.
I purchased these intake valves , and these exhaust valves .
First are sourced from Germany, second are Vesrah. Not sure exactly what the intake are. They look good and solid. But the profile is a bit different - the curve leading to the stem is not as steep. Says 'Racing (High - Performance) Valve. 12004-1004 SUH3HT Which points to Germany.
I need to change only a few valves, but I will probably just install the whole set of six intake. I need just two exhaust, so I bought just two. Looking at the profiles, I think these are lighter than stock, and it makes me wonder a bit if having a mix is not desirable.
So I am wondering if it's ok to just replace the 2 exhaust and leave the four original. All the seats will need some machining as well. And two guides replaced(bought oem from Kawasaki)

I am on the same boat! I think we bought the same valves. I will let you know what's happening, although it's a very long road for me before I will fire up the engine.

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Kawboy's restoration/conversion of a 1980 KZ13 6 years 5 months ago #17481

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The company who supplied your intake valves in Germany also offered a complete set of valves for $263 U.S. plus $9 for shipping. That's what I bought. It will be interesting to see what they look like and how they perform.
Next on the shopping list will be a 4 or 5" silicon carbide grinding wheel for the camshaft grinder Then I'll be looking for an electric motor around 3" in diameter that can spin the stone at 3500-4000 rpm.

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Kawboy's restoration/conversion of a 1980 KZ13 6 years 5 months ago #17482

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The company who supplied your intake valves in Germany also offered a complete set of valves for $263 U.S.


Yes, I know. Kind of regretting not getting the whole set instead of getting just those two Vesrah exhaust valves separate. Basically 5 of my exhaust valves are fine, so I was just trying to save funds for endless list of other things... Will see how they look and what happens. Good thing is those German sourced valves are available.

Are original seats still available? The valve guides are, just in case.

Probably all of my seats need some light machining. I feel a bit scared now, haha One shop specializes in motorcycles here and has a great reputation but big dollars. Another also very good reputation, cheaper, but majority of their work is all sorts of car and truck engines. I'd do it by hand if I could source the right set of valve seat cutters.

It seems like you have a real big custom job on your hands, to custom fit each valve.. I wish you success and hope to see a couple of photos!

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