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Discussion Starter #1 (Edited)
Reassembling z400. When I begin to tighten down the caps on the cams the cams sieze with the slightest pressure on a bolt. I run the bolts down by hand. And if I turn even one bolt a 16th of a turn the cam won't spin. I've oiled everything. Have the right bolts in the right holes. I torqued the head down to spec. The lobes are not in contact with the Buckets. It's the same stock stuff I pulled out. I have ethernet cam chain off the cams. Put new valves and seals in. Had the valve seats cut. Was trying to shim the valves when I ran into this problem. How freely should that cams move when torqued down.
 

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just how much torque did you put on the cap screws ?
 

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Discussion Starter #3 (Edited)
None, finger tight plus a 16th turn on bolt and it puts resistance on cam. Guess I don't know how freely the cams should spin when it's all torqued down. Right now you grab gear with hand and gotta push to get it to spin.. Can't just move it with fingers
 

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you could try some plastic gage to find out how tight it really is
 

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I guess I would make sure the cams are all the way in the grooves with the cap off, and see if they turn freely.. Wonder if you might have bumped them when you had the head off? All the edges look good? I have never really checked mine, but have heard of them becoming tight, and a machine shop fixing it, though I think you could do a little yourself, if you were careful. Guess I will make it a point to spin mine by hand next time, so I know..
 

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It sounds like they aren’t in their original positions. The exhaust cap behind the sprocket is a no-brainer since it has the oil passage in it, but the others could have gotten switched around.

This is the same head and cam caps that were on the engine before, right?
 

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I guess I would make sure the cams are all the way in the grooves with the cap off, and see if they turn freely.. Wonder if you might have bumped them when you had the head off? All the edges look good? I have never really checked mine, but have heard of them becoming tight, and a machine shop fixing it, though I think you could do a little yourself, if you were careful. Guess I will make it a point to spin mine by hand next time, so I know..
could it be he does not know what plastic gage is ?
 

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It's not clear to me. Has everything being assembled been together in the engine before or are you putting used parts together? The cams spin freely even if you over torque the caps. Over torquing the caps just tears the threads out of the holes. It's not like the LTR where the caps put pressure on the cams if too tight. I'm curious if a previous owner bought used caps and didn't custom fit them and passed it along to you when it wouldn't work right. Also possible that you have galled aluminum on the cams or cam journals making things tight.

I've made used caps work, but you need to properly fit them by pretty delicate means. It's one of those jobs that if you have to ask how, you shouldn't be doing it.
 

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It's not clear to me. Has everything being assembled been together in the engine before or are you putting used parts together? The cams spin freely even if you over torque the caps. Over torquing the caps just tears the threads out of the holes. It's not like the LTR where the caps put pressure on the cams if too tight. I'm curious if a previous owner bought used caps and didn't custom fit them and passed it along to you when it wouldn't work right. Also possible that you have galled aluminum on the cams or cam journals making things tight.

I've made used caps work, but you need to properly fit them by pretty delicate means. It's one of those jobs that if you have to ask how, you shouldn't be doing it.
That’s what I was getting at. Has it run since he’s owned it?
 
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