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Checking valve clearances with the head off?
- polkat
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And should the noses of the lobes be 180 degrees away from the buckets when doing measurements?
Finally, is there a problem with swapping the shims around to bring clearances closer to stock? Thanks!
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- Jack
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Yes. Remember ONE cam at a time
Yes.
No problem.Cuts down on $$ shim inventory required.
If I can do it you can. Get a good manual, good luck.
79 KZ 1075 MKll
79 KZ 1500 MKll dragbike
Gone but not forgotten:
3 X 73 Z1's
1 X 74 Z1A
1 X 75 Z1B
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- testarossa
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- Attack life, it's only trying to kill you.
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As for swapping the shims...Swap away! The one time you won't get in trouble for swapping!:laugh:
1978 KZ1000 A2 Click--->Build Thread
2004 ZX-10R
2007 Harley Sportster 1200
2020 Harley Street Glide Special
Angola, IN
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- TeK9iNe
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- What did you do!?!
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Place a piece of towel down on the front or rear edge of the head, then you can wedge the driver in the cam gear and pry the cam gear upward a notch at a time.
Towel preventing damage to gasket surface of course.
GL
Motorcycle Shop Owner/Operator
79 Kawie Z1000 LTD
81 Kawie Z1000 CSR
83 Honda VT750C A
85 Kawie GPZ900 A2
86 Zukie GS1150 EG
93 Yamie XV1100 E
Lucky to have rolled many old bikes through my doors
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- gane
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[img][/img] 1977 KZ1000A1
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- wrangler615
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my .02
83 Kaw KZ750F1 - massive money pit
82 Zuki GS1100G - my daily driver, possible sacrilege I know
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- bountyhunter
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1979 KZ-750 Twin
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- polkat
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My manual says that cam to bearing clearance should be about .19mm, half of which should be about .095mm clearance all around the cam when it is spinning in a bed of oil, which will, of course, hydroplane it off the bearing surfaces.
So, if I torque the cams in and then push down on it while taking the readings, seems I should be able to get pretty close. Even if the cam did shift downward from chain tension, which I wouldn't have with the head uninstalled, seems that I'd get ever so slightly more clearance then wanted, which is better then slightly less.
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- OnkelB
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As shown in the pic I also like to set the head on a couple of wooden blocks to raise it from the workbench - as you rotate the cam the valves will poke out beneath the head, if the head is flat on the workbench you risk bending a valve (might not happen, but better safe than sorry).
I find the easiest way to rotate the cam is to mount a cam sprocket bolt in the cam and use a 10 mm wrench.
77 KZ 650 B1, 82 GPz 1100 B2.
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- Tyler
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bountyhunter, let me see if I follow you. The clearance between the cam bearing journals and the bearing area is compressed downward by the chain tension, slightly changing the readings?
My manual says that cam to bearing clearance should be about .19mm, half of which should be about .095mm clearance all around the cam when it is spinning in a bed of oil, which will, of course, hydroplane it off the bearing surfaces.
So, if I torque the cams in and then push down on it while taking the readings, seems I should be able to get pretty close. Even if the cam did shift downward from chain tension, which I wouldn't have with the head uninstalled, seems that I'd get ever so slightly more clearance then wanted, which is better then slightly less.
I have bench shimmed a head on my 650. I checked it after I installed it and ran the engine for for a short ride down the street and found the identical clearences as I did on the bench. I wouldn't worry too much about dynamic oil film or can chain force, you will be just fine shiming it properly off the engine. sincew I had ground the valves and setas I set the clearences up near the top end and tried to get them all within a thousandth. That gives me some room as the valves fin thier new home in the seats.
Just my 2 cents.
If I knew what I was doing all the time life wouldn't be any fun.
'80 KZ650 E 700cc, dyna ignition and coils, frame up restoration, daily driver
'81 KZ1300 A3 full restoration, custom big bore pistons, 1400cc 6 cylinder super bike
"77 KZ650 B1 - Barn Find, work in progeress
"74 Yamaha DT 400 Enduro
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- bountyhunter
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Does on mine, I have two shims that will change about .002 by releasing chain tension. I checked cam journal clearance and they are in spec.bountyhunter, let me see if I follow you. The clearance between the cam bearing journals and the bearing area is compressed downward by the chain tension, slightly changing the readings?
polkat wrote:
I think you want spec clearance with the thing installed and torqued down, and chain pulling down the cam which will close down the clearance a bit compared to "no chain" reading.So, if I torque the cams in and then push down on it while taking the readings, seems I should be able to get pretty close. Even if the cam did shift downward from chain tension, which I wouldn't have with the head uninstalled, seems that I'd get ever so slightly more clearance then wanted, which is better then slightly less.
1979 KZ-750 Twin
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- fast_johnny
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1977 KZ1000A1 1075cc, Kerker, Cavanaugh Head, RS34s
1995 KZ1000P
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