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I'm escared....really escared
- gsnfl
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KZ650C-1 basketcase that I pretty much was getting there for the last year however a bitch to start. Took starting fluid if the engine was cold and sometimes when hot. Sat a couple weeks while I was gone and it wouldnt start. I finally got a backfiring beast running with copious amounts of spray and it runs like crap for about three miles then kinda smoothes out (mostly). I was leaving again so I take it to a trustworthy shop for a look see on its bad manners. Timing set perfectly, valve clearances checked, carbs synched but it wont start for him either. He does some research and finds that the PO installed the crank 180 out.
My first question...How the hell did it EVER run like this?
So he installs the crank properly and it still wont run. Compression is found to suck (errr...not suck?) at numbers like 40, 60, 95 and 70. Damn
"Rings!" I say....then I re-think before spending the fist-full of dollars that OEM rings run for this (HOLY SHEEP). I agree to a head peek to see if all the valves are bent before I spend.
Question 2- 180 out crank=guaranteed bent valves?
He can't get back to it for a few days so now the fear has set in. I'm like 500 in the hole on labor here already and at what point do I say enough. Its not a pretty KZ but I dont want to quit yet. At some point common sense will have to take over before my wife cut my nards off over this. Its a 77 with 27K on it and I originally paid 500.00. I was at about 1500 in with tires and odds and ends until today and now I rolled over 2k.
Its not my first bike by any means but I've never-ever had trashed engine...even on my Z-1 so the fear begins to creep in. When is when enough?
Thoughts? Therapy? Kind words? Mockings?
I'll be in the head puking.
77 KZ650 C1 basket case project-blowed up and parted out
83 KZ550 M1-Prince to Toecutter transition
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- baldy110
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- gsnfl
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All that was done and it wasn't stored a long time at all..in fact it was running pretty good (ok, fair) til I split for about ten days (not enough to varnish).
77 KZ650 C1 basket case project-blowed up and parted out
83 KZ550 M1-Prince to Toecutter transition
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- wireman
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Check the timing marks under the points cover,bring motor up to tdc by turning motor over by hand with the plugs out.
Then pull the valve cover off and check the timing marks on your cam sprockets compared to the picture in your manual,its very unlikely your cams are far out of wack on a reasonably decent running motor unless your cam chain somehow commited suicide by jumping several teeth finishing itself off .
posting from deep under a non-descript barn in an undisclosed location southwest of Omaha.
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- bountyhunter
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Those compression readings definitely mean bad valves of some form or fashion.
1979 KZ-750 Twin
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- bountyhunter
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original coils?gsnfl wrote: Back story:
KZ650C-1 basketcase that I pretty much was getting there for the last year however a bitch to start. Took starting fluid if the engine was cold and sometimes when hot. Sat a couple weeks while I was gone and it wouldnt start. I finally got a backfiring beast running with copious amounts of spray and it runs like crap for about three miles then kinda smoothes out (mostly).
1979 KZ-750 Twin
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- Motor Head
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You didn't do a compression test yourself sometime recently before taking to a Shop did you? The symptoms of being extremely hard to start, and running poorly could very well be low compression. Why hasn't he Shop done a Leak Down Test to tell you that you have Bad/ Bent valves? This would be the Next step after such a low compression test. Find out where its leaking, and decide if you want to put more $ into it at that Shop. $500 already and no Joy, Ouch!
1982 KZ1000LTD K2 Vance & Hines 4-1 ACCEL COILS Added Vetter fairing & Bags. FOX Racing rear Shocks, Braced Swing-arm, Fork Brace, Progressive Fork Springs RT Gold Emulators, APE Valve Springs, 1166 Big Bore kit, RS34's, GPZ cams.
1980 KZ550LTD C1 Stock SOLD Miss it
1979 MAZDA RX7 in the works, 13B...
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- steell
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bountyhunter wrote: If the cams were 180 off the engine could not run. Perhaps he meant that the PO installed the cams wrong, bent the valves, then corrected it and dumped the bike on the next unsuspecting owner.
Those compression readings definitely mean bad valves of some form or fashion.
If the cams are 180 out and you rotate the crank one more time they will be in time again.
Remember, cams turn at 1/2 speed of crank.
Ignition timing could be 180 out though, since it runs off crank.
KD9JUR
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- gsnfl
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Leak down test is tomorrow or maybe the day after. I'm hoping for the best but expecting the worst.
77 KZ650 C1 basket case project-blowed up and parted out
83 KZ550 M1-Prince to Toecutter transition
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- gsnfl
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77 KZ650 C1 basket case project-blowed up and parted out
83 KZ550 M1-Prince to Toecutter transition
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- bountyhunter
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But that can't be the problem according to the OP: he said it ran but crappy. If the timing advancer was 180 off, it could not run at all.steell wrote:
bountyhunter wrote: If the cams were 180 off the engine could not run. Perhaps he meant that the PO installed the cams wrong, bent the valves, then corrected it and dumped the bike on the next unsuspecting owner.
Those compression readings definitely mean bad valves of some form or fashion.
If the cams are 180 out and you rotate the crank one more time they will be in time again.
Remember, cams turn at 1/2 speed of crank.
Ignition timing could be 180 out though, since it runs off crank.
My point was that maybe he installed the cams wrong (off some amount) and bent the valves then set the cams on right. That would result in bent valves, poor compression, and running like crap.... which sounds like what he has.
If these numbers are accurate:
Compression is found to suck (errr...not suck?) at numbers like 40, 60, 95 and 70. Damn
I guarantee it's not an ignition timing problem. Either the cam timing is way off or the valves are bent. Bad rings? I had 75000 on my engine at the rebuild and the rings were still holding about 125 PSI cold/dry. Rings are not all going to break in unison and give you 40 - 70 PSI readings. Has to be a problem with the valves.
First thing I would have done is to take the head off, flip it upside down and fill the combustion chambers with light oil and watch to see if it drains out past the valve seats. If it does, the valves are hosed and the head needs to be rebuilt.
1979 KZ-750 Twin
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- trianglelaguna
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it is an age old formula and these numbers move around some but not much
if the bikes psi is down with the cams on the right teeth and ignition timing right...then you need head work...get an ltd-kz-sr-csr 650-750 motor for 200 and be free of this one ,fix it later
1976 KZ900
2003 ZX12R
2007 FZ1000
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