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Best way to test 0 clearance valves?
- staniel
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I haven't checked what shims are in there yet, but the measurements I got are as follows
Exhaust
1: 0.063 mm
2: 0.178 mm
3: 0.076 mm
4: ZERO clearance
Intake
5: ZERO clearance
6: 0.076 mm
7: 0.102 mm
8: ZERO clearance
I noticed that the four outer valves are the tightest, including 3 which now have no clearance (couldn't even force the 0.038 mm feeler in there). Odd coincidence or does this happen often?
I'm pretty confident I know what to do with the other 5 valves, but what's the best way to test the ones with zero clearance? Pull all the buckets, remove and measure all the shims, insert the smallest one into each of the zero clearance valves and go from there? It's a drag you have to reinstall the camshafts every time you test.
Help me out, o ye sources of KZ experience and wisdom! (How many decades of KZ mechanic experience do y'all think we have on here? I can offer .25 years.) The fewer times I have to torque wrench the camshaft caps on, the better!
1983 KZ750 L3 with 4-1 Kerker pipe and pods
1983 KZ750 L3 parts bike
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- Old Man Rock
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If no markings then use a digital caliper.... Actually prefer this method better....
Z1 has shims...
www.z1enterprises.com/catalog.aspx?pid=KZ650-B1-1977-EN1
EDIT: Just realized you most liekly have 13mm shims KZ650....
1976 KZ900-A4
MTC 1075cc.
Camshafts: Kawi GPZ-1100 .375 lift
Head: P&P via Larry Cavanaugh
ZX636 suspension
MIKUNI, RS-34'S...
Kerker 4-1, 1.5" comp baffle.
Dyna-S E.I.
Earls 10 row Oil Cooler
Acewell 2802 Series Speedo/Tach
Innovate LC1 Wideband 02 AFR meter
Phoenix, Az
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- testarossa
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- Attack life, it's only trying to kill you.
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If not, then there is no clearance, and you should replace that shim with one of the smaller shims that you have from another valve. Then you should be able to measure the clearance from there.
Last, what model bike is this? Does it have the shims on top of the buckets a-la KZ1000? If so, then you can get a tool that will press the bucket down and hold it there so that you can get the shim out without removing the cam. Like this one:
www.z1enterprises.com/detail.aspx?ID=152
1978 KZ1000 A2 Click--->Build Thread
2004 ZX-10R
2007 Harley Sportster 1200
2020 Harley Street Glide Special
Angola, IN
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- Patton
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On those with ZERO clearance:
With cam lobe pointing away from bucket, see whether the shim will turn (indicates minimal clearance), or whether it won't turn, being too tightly held by the cam base (indicates no clearance).
If shim will turn, would replace existing shim with next size thinner shim.
If shim won't turn, would replace existing shim with shim two sizes thinner.
Gap on exhaust #2 is a little too wide. Likely needs two sizes larger shim.
It may be possible to swap exhaust #2 and the 4 zero clearance shims around to achieve clearances within spec on those needing adjustment.
Good Fortune!
EDIT:
Just noticed: Pull all the buckets, remove and measure all the shims, insert the smallest one into each of the zero clearance valves and go from there? It's a drag you have to reinstall the camshafts every time you test.
So likely dealing here with shim under-bucket, whereby above suggestions for over-bucket won't be very helpful.
1973 Z1
KZ900 LTD
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- Patton
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Click here > kzrider.com/index.php?option=com_kunena&...d=8&id=382004#382317
Good Fortune!
1973 Z1
KZ900 LTD
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- staniel
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Yes, I have shims under the buckets on my 1983 KZ750 L3 4 cyl ( at Patton). I tried spinning the buckets with my fingers but they went nowhere. I'll be a little more thorough next time. Supposing I have zero clearance, I'll try to do something clever so I don't have to order a whole fleet of shims at $5 each.
I was just hoping there was some trick for this scenario since, for any other measurement, math is sufficient.
1983 KZ750 L3 with 4-1 Kerker pipe and pods
1983 KZ750 L3 parts bike
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- testarossa
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1978 KZ1000 A2 Click--->Build Thread
2004 ZX-10R
2007 Harley Sportster 1200
2020 Harley Street Glide Special
Angola, IN
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- Jeff.Saunders
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Most times that's going to be fine.
If you did end up needing an even thinner shim, you are likely to have valve seat damage and chances are you would not get good compression after correcting the clearances.
Running an engine with valves that don't close fully causes hot exhaust gases to work past the valve - this causes 'burning' of the valve/valves seat.
This is all assuming the reason for the zero clerance is normal wear. If a previous owner reinstalled cams with the shims shuffled, is would be anyones guess as to what to use without installing thinner shims and rechecking.
www.z1enterprises.com
Z1 Ent on Facebook,
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- staniel
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I'm gonna guess that what happened here is the valve lapping and seating surface work brought the valves in a little closer than they were before. I don't believe this was happening before I got that work done (although bad compression might explain why I only got 37mpg)
I will not be running this engine until the clearances are within spec. I think I'm gonna aim for .07mm to .08mm clearance, given that people all say the clearances shrink after the first few runs.
1983 KZ750 L3 with 4-1 Kerker pipe and pods
1983 KZ750 L3 parts bike
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- Patton
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...gonna guess that what happened here is the valve lapping and seating surface work brought the valves in a little closer than they were before. I don't believe this was happening before I got that work done...will not be running this engine until the clearances are within spec. I think I'm gonna aim for .07mm to .08mm clearance....
What are factory specs for valve clearances on 1983 KZ750 L3 ??
Where thinner shims aren't available, it may be feasible to grind down (tip) the valve stem, which slightly shortens its length and thereby allows a thicker shim.
Must carefully follow FSM instructions about such procedure.
Good Fortune!
1973 Z1
KZ900 LTD
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- staniel
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1983-on Non-turbo
Valve/guide clearance (rocking method)
All valves - 0.013 in - 0.33mm
This sounds extremely high for what other people's bikes are requiring here (generally 0.5mm-0.15mm).
Does this sound normal for a KZ750L3?
The guy at this thread says the clearance spec is .08-.18...
kzrider.com/index.php?option=com_kunena&...d=2&id=226002#226145
Any guidance would be greatly appreciated. Meanwhile I'll do math to try to get the clearance to between .10 and .13.
Shim measurements, for anyone curious, were
Ex
1. 260
2. 250
3. 250
4. 260
In
5. 245
6. 250
7. 240
8. 250
1983 KZ750 L3 with 4-1 Kerker pipe and pods
1983 KZ750 L3 parts bike
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- 650ed
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....I don't believe this was happening before I got that work done (although bad compression might explain why I only got 37mpg)...quote]
37 mpg is not bad or unusual although some folks report getting better. My '77 KZ650-C1 has never gotten more than that since I bought it new (granted, I drive a little bit on the spirited side). Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)
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