Thanks for your input.
Is 110 PSI compression ok?
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Is 110 PSI compression ok?
I have a 78 gs750 with 31K miles on it. I checked the compression in all cylinders the other day and they were all 110 PSI +/- a few pounds. I put some oil in the cylinder for the second reading and found that the pressure went well over 150 PSI in all cylinders. It seems the valves are ok, but should I be worried about the compression? The service limit is 100 PSI. How much longer can I expect to ride this bike? I guess you should know that I'm not afraid to red-line it once in a while. I just ordered 3 Ohm Dyna coils and Dyna-S electronic ignition and I'm wondering if I should return them and use the money to rebuild the cylinder instead.
Thanks for your input.Tags: None -
Spyderman
that compression is fine for some time yet put the coils and ignition on and enjoy the bike no need to worry yet -
Guest
I know blokes that have raced them with 70 psi so you should be ok for a while yet. Cheers , Simon.
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mighty13d
so it's the rings that aren't keeping the compression up... have you been running it this way for a while? if not, then the rings might loosen up and actually raise your compression after a while.Comment
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B-rent
This is the first time I have checked them. I have had the bike for about 2 years now and it seems to perform the same as when i first bought it. I will have to check them again after a while and see if it improves or gets worse.Comment
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How long since your last valve adjustment?Ed
To measure is to know.
Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182
Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846
Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf
KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-ResurrectionComment
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Jeeze, This thing again, adjust the valves, tune it up and run the hell out of it.
Probably it's weak because some wimp actually followed what they read in the owner's manual about taking it easy during break in thirty years ago.
It will be fine until it blows.
Rocket science.Last edited by tkent02; 09-20-2009, 01:52 AM.Comment
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B-rent
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Why would changing the springs help? New springs if anything will have more seat pressure which will increase wear.Ed
To measure is to know.
Mikuni O-ring Kits For Sale...https://www.thegsresources.com/_foru...ts#post1703182
Top Newbie Mistakes thread...http://www.thegsresources.com/_forum...d.php?t=171846
Carb rebuild tutorial...https://gsarchive.bwringer.com/mtsac...d_Tutorial.pdf
KZ750E Rebuild Thread...http://www.thegsresources.com/_forum...0-ResurrectionComment
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B-rent
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Just take it in to the red zone a few times - it'll be fine.79 GS1000S
79 GS1000S (another one)
80 GSX750
80 GS550
80 CB650 cafe racer
75 PC50 - the one with OHV and pedals...
75 TS100 - being ridden (suicidally) by my fatherComment
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B-rent
It doesn't burn any oil that I can see, and I never have to add oil between oil changes. I really want to tear into it, but I want to make sure I have a good reason to before I screw something up. I probably won't be doing this for a while. I've been looking for a parts bike to screw around with but they are hard to find around here in Idaho (I check craigslist at least a couple time per week) and it seems people want money for them too, crazy. When I bought this bike I knew nothing about it and thought I would be lucky to get one season out of it before it died. I was very wrong about that.Last edited by Guest; 09-20-2009, 10:57 AM.Comment
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Pete Logan
Just thrash it. If it's not using any oil then it's gonna go at least twice that mileage before it starts to. And then the same again before it needs any attention beyond regular servicing.Comment
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Agreed, run the crap out of it, it is all good. Buy a dead Honda or a lawnmower or something to take apart. It's just as much fun.Comment
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