Low Compression

  • Powerstroke_fan
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Re: Low Compression

10 Jun 2013 21:43
#591669
I would think you would be ok as long as your measuring the bottom of the lobe.
1980 kz1000B4 LTD- 1327cc 9-1 comp
Ported J model head
Psp-3x cams
RS 36s
Welded MK11 crank
Back-cut MK11 trans
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Stretched 4-6 over running Hayabusa rear rim with 190 rear tire
Complete frame brace kit installed
And Much Much more- SOLD

2014- ZX14R all stock for now

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  • BIGKEVIN
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Re: Low Compression

10 Jun 2013 22:00
#591675
I will take the readings again tomorrow and post the fings. I just want to make sure that the valve clearances are withing tolerances.
1976 KZ900
2006 ZX6R

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Re: Low Compression

11 Jun 2013 13:33
#591757
I took the readings again and swapped some shims around to get 4 of the clearances within tolerance.
The #2 intake is too loose with a 2.5 mm shim, but too tight with a 2.3 mm shim, the smallest feeler gauage I have wont fit. Should I order a 2.4 mm shim or a 2.35 shim ? I have the smae issue with the #4 exhaust, 2.5 too tight and 2.3 too loose. Should I order 2.4 or 2.35 ? The #3 intake has a 2.7 shim in it and the .051 mm gauage fits. Is that too tight ? Should I order a shim for it while order others ? The #3 exhaust has a 2.5 shim that is too tight and 2.6 is too loose, so it looks like a need a 2.55 shim for that one. Any help would be appreciated.
1976 KZ900
2006 ZX6R

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Re: Low Compression

11 Jun 2013 19:36
#591803
Anyone have any replies ? Don't want to seem pushy, but I am trying to get the parts ordered tonight so they can be shipped tomorrow morning.
1976 KZ900
2006 ZX6R

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Re: Low Compression

11 Jun 2013 21:40
#591827
Too tight clearance needs thinner shim to increase clearance.
If a too tight shim turns, order 1 size thinner shim.
If a too tight shim won't turn, order 2 size thinner shim.
Need 0.05~0.10mm clearance for intake valves.
Need 0.05~0.15mm clearance for exhaust valves.

Good Fortune! :)
1973 Z1
KZ900 LTD

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Re: Low Compression

12 Jun 2013 00:17
#591866
So is the .051 feeler gauge the only one you are using? Saying it is too loose or too tight is just a subjective measurement...you need an actual number or you will never get it right. I will reiterate that the best thing to do is to get a set of metric feeler gauges and go from there (a set that includes .04, .05, .06, .07, .08 and .09 is essential) You have to be able to get a feeler in there, only then will you know what shim to order based on the gaps the manual and others have outlined. :)
79 KZ 1000 LTD
77 KZ 1000 B1 LTD (awaiting electrical resurrection)

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Re: Low Compression

19 Jun 2013 21:01
#593137
I ordered shims last week from Z1 and installed them all today. The #4 exhaust is tight. The biggest gauge that will fit is a .051 mm. It has a 2.5 mm shim in it and with a 2.3 mm shim, the clearnace is too loose. I was going to order a 2.4 mm shim from Z1 but they are out of stock. Will a 2.45 shim be good since the .051 mm gauge fits with the 2.5 mm shim installed ? Thanks for any advice.
1976 KZ900
2006 ZX6R

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Re: Low Compression

25 Jun 2013 21:44
#593934
I got all my shims and now have the following:

#1 intake - .102 mm biggest gauage that will fit
#1 exhaust - .127 mm biggest gauage that will fit
#2 intake - .102 mm biggest gauage that will fit
#2 exhaust - .152 mm biggest gauage that will fit
#3 intake - .051 mm biggest gauage that will fit
#3 exhaust - .152 mm biggest gauage that will fit
#4 intake - .063 mm biggest gauage that will fit
#4 exhaust - .102 mm biggest gauage that will fit.

The bike started, but now I have oil leaking from what appears to be the #3 header pipe. I don't see any oil above the exhaust system. I will see about finding where the oil is leaking from tomorrow. I had this same problem before and if stopped after taking the exhaust off and seeing everything good and then putting it back on. I'll do the foot powder trick that Patton suggested when I had this issue before.
1976 KZ900
2006 ZX6R

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  • 650ed
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Re: Low Compression

25 Jun 2013 22:44
#593941
Double check to make sure the oil isn't coming from the tach drive seal. That's a common leak and it's pretty close to the #3 pipe. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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Re: Low Compression

26 Jun 2013 19:44
#594033
I think I found the leak. I started it today and the header started smoking. I checked everything and found that there was a small leak from the valve cover. I took the tank off and some of the valve cover bolts were not tight. I make sure that they were all tight and took it for a quick ride and did not see any smoke. Should I have put lock tight on the valve cover bolts ? What is the best way to clear the foot powder from the front of the motor ?
1976 KZ900
2006 ZX6R

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Re: Low Compression

26 Jun 2013 19:55
#594034
No, do not use lock-tite on the valve cover bolts. Just torque them to spec (61 - 78 INCH pounds) and they will be fine. Ed
1977 KZ650-C1 Original Owner - Stock (with additional invisible FIAMM horn)

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Re: Low Compression

27 Jun 2013 21:38
#594164
I did the compression test again after getting the valve adjustments completed. Before the valve adjustments, all of the compressions read between 70 and 85 psi. I checked them today and #1 is 120, #2 is 110, #3 is 95 and #4 is 115. Are those readings goog for a 1976 KZ 900 or should they be higher ? I have not rode the bike after doing the valve adjustments yet, but I am hoping to be able to do it tomorrow.
1976 KZ900
2006 ZX6R

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