Rebuilding top end on a 74 z1 900?

im going to take the z1 all apart over the winter, my question is how hard is it to put new valves in? The old girl just turned over 18,100 origanol miles. But she did sit from 1983 to 2004. When i put the 4 into 2 pipes on i realized the ezhaust valve on the 1st cylender had a whitish color to it, but there was no performence loss, so i didnt really think anything of it. I was also wondering if there was any were i can get an OEM cam chain adjuster, becouse i really dont like the manual one on here, it seems like i can never get her quite right.

Ii hope you get some answers cause after i get the eliminator going im' gonna pull the 73' Z off the shelves.

probably just needs a valve job while its apart,no need to replace valves if they are still grindable;)

While I don't know the history of the bike, 18000 original miles is barely broken in...so what is probably required is to lap the valves, replace valve stem seals, and all those rubber bits that have to do with cam chain adjustment...some of those can be pricey but all cam chain adjustable bits are still available though www.z1Enterprises.com The big killer of these old, but low mileage motors is time, as the rubber tends to deteriorate.

Ya,You'll want to for SURE,at the very least,replace the valve-guide seals.
Get ahold of a spring compressor ahead of time(Jeff at Z1 has them),so You can get going on taking it all apart.It's not too bad of a job,and just keep track of all parts You remove.Keep all cylinder #1 components together,#2 components together,etc. etc.
Drill a hole in a length of lumber to hold the valves as well.
You really should plan on spending some money in there too(while You're going through all that trouble)...don't cheap out or it'll bite Ya where it counts.
Doing it Yourself will justify You purchasing some specialty tools for the job,and You'll STILL be money ahead for SURE!...WIN WIN!:woohoo:

I doubt you will need to replace the valves with that kind of milage. Probably just guides and a valve job.

One of the good things about doing seat work on these old heads is todays state of the art seat machines can do seat cuts that couldn't be done in the 70s,. Besides redoing the valve seal, better flow results past the seats, increasing the performance.

Jay

How much flow increase are we talking about here?

As posted above, all you probably will need is to lap the valves and seats and replace the valve stem oil seals. I doubt if your valve guides will need replacing with that many miles on the bike. Z1 sells a great valve spring compressor kit for 40 some bucks. Well worth it. Makes removing the valve springs easy. You might want to replace the rubber carb manifolds while you have the head off. It is easier that way and in case you break off a bolt, it is easier to fix. You will have carbon buildup on your cylinder head. Pick up a Dremel tool and some wire brushes. Makes removing the carbon easier and the surface will be smoother too.....chris3

yea ill do that all this winter, thanks for the sugestions. I just replaced the carb manifold bots about a month ago, because the old ones were stiff and had cracks everywere.

I know if I had the engine apart I would replace everything I question myself about. I would hate to put it back together saying shoulda woulda coulda:sick: . Expecially whan it comes to heads. I would at LEAST do the valve grind on intake, replace the exhaust valve, and seat, new valve stem seals, and new springs, and cam chain.

For performance part and longevity I would replace valve guides, Stainless valves, titanium retainers, along with the list above.

Hey oldkaws4ever... No one actually gave you the advice you need... DO YOU NEED NEW VALVES? To figure this out, you can do it WITHOUT removing the cylinder head. Check your valve clearances. If you need a bunch of the skinniest shims, the seats are worn and if I were installing new seats, I would replace the valves at the same time as the valves are likely tired as well. As has already been noted, this is unlikely at 18K miles but check your valve clearances and if you need a bunch of 200 shims or can get the correct clearance at all because no 180 shim exists, think about a new cylinder head or new valves, seats, valve job, etc.

In fact, at 18K miles you may or may not need to have a valve job or guides. To tell, you need to pull the head and disassemble. Wiggle the valve stems in the guides... if you can rock them, they are shot. If they are OK, then lap the valves into the seats after cleaning things up and use some machinists dye to determine if you have good seal. You paint this stuff on the mating surface of the valve and drop the valve into the seat WITHOUT ROTATING IT and then pull it out. A good seal will be indicated if you have a good clean line around the seat. If the line is broken, you can try lapping some more but at some point will want to have a valve job done.

Who could do a valve job? I sure wouldn't take the bike to a local machine shop unless they specialized in bike engine builds... the reason is that the car oriented places generally have a heavy hand and will grind your seats into nothing. Send the head to someplace that specializes in bike work... they have a light touch and just remove enough material to get your valves seated good... you hardly need to lap after a good shop does this job. Jay can probably recommend a place like this bwhahaha My friend Robby at RLM Motorcycles in San Antonio does my machine work but I suspect when he retires, I will have to start mailing off cylinder heads as there are not all that many local places left doing this work. High tool investment, high skill required and I suspect they dont' get rich with just a local market probably keeps a lot of guys out of the bike machine shop business.

he just asked how hard it was to replace the valves since he was tearing the bike all apart,i think the suggestions he got went well above and beyond what he was asking for.if he would of asked how to know if his motor needed rebuilt that would of been differant.