QuestionHistory of Ownership:
I have a 1984 Kawasaki LTD 700 [model: ZN 700-A1; engine family: ZX700A]. The motorcycle has relatively low mileage (12,300 miles) and to the best of my knowledge (and based on its pristine condition), it has been well cared-for and maintained (I bought the bike in April 2003). I rode the motorcycle last year and put aprox 3,500 miles on it. It perform very well and gave no indication of any problem or system failure. Over the winter non-riding season [2004] a complete maintenance was done including: replacement of all fluids and filters, cleaned and strengthened electrical wiring/connections (as appropriate) , new battery, replaced fuel valve and lines, checked valve clearances, replaced spark plugs, mounted and balanced new tires (front and back), and a thorough clean/polish of the bike stem-to-stern. I resumed riding the cycle in May 2004 ... the cycle performed flawlessly and gave no indication of any potential problem. I logged aprox 700 miles before I experienced the present engine/drive-train trouble/failure.
Engine Failure/trouble:
I was riding on an Interstate highway with a sustained speed of 65-70 mph when I heard a single loud "bang" that seem to originate from the lower engine/transmission case (similar to an object hitting the lower engine/drive-train housing that was kicked up from the front wheel). There were no other unusual noises or indications of engine problems so I continued traveling on the interstate highway. About 50 miles later (35-40 min. of driving), I experienced a significant reduction in power and blue-gray harsh-smelling smoke coming off the engine. The engine did not seize; but it did stop completely. The blueish smoke continued to come off the hot engine; but I could not pin-point any specific source of the smoky fumes. There did appear to be evidence of a slight oil leak on the front of the engine based on some oil residue and a small amount of oil seepage from the valve cover. I did not try to restart the bike while it was hot and smoking. No warning lights (oil pressure, generator) were lighted during the "smoky engine failure" (the warning lights were operational). After 10-15 minutes and the engine had cooled, I tried to start the bike. The starter cranked the engine without noticeable restriction; the cycle did not start At this point, the motorcycled was towed to [my] home garage for further diagnosis/disassembly and repair.
Home diagnosis/repair efforts:
A compression test revealed reasonably consistent compression among cylinders 1, 3, and 4 within the range of 115-125 psi. Cylinder #2 registered 65 psi. There was no noticeable difficulty for the starter to crank the engine to do the compression test (the transmission was in neutral). Inspection of the 4 sparkplugs showed no evidence of oil fouling or oil combustion ... all 4 plugs had uniform and appropriate appearance from normal operation. The exhaust system/mufflers showed no atypical combustion (i.e. oil consumption). A small amount of oil seepage was observed by the valve cover gasket in the front of the engine. Removal of the valve cover reveal nothing to indicate any problem (other than a need to replace the gasket) ...no evidence of: blow-back, clogged oil lines/ports, worn cam shaft bearings, valve leakage. There was no atypical resistance to valve action or rotation of the engine crankshaft. There was no atypical nor excessive wear to any the components housed under the valve cover. All valve clearances were within specified ranges.
The engine head was next removed. No unusual conditions were observed ... head bolts(2) and stud nuts(12) were in good condition. No seized nuts/bolts were encountered in removal of the head or exhaust system. All cam cap bolts appeared normal and of uniform tightened torque. The engine head was removed without problem and no significant problem was observable from that level of disassembly. The head gasket was intact (I had thought a failed head gasket would explain the symptoms), there was no evidence of: cylinder wall scoring, atypical piston wear/appearance, leaky valves, burned valves (all looked uniform and error-free), warped head, warped block, warped valve cover, or casting irregularities of block/head/valve cover. There were no noises during shut down on the interstate to suggest connecting rod/bearing failure nor main bearing failure. It is very possible that the sudden loss of power may have been caused by low fuel levels (135 miles on a full tank of gas); but that wouldn't explain the smoking engine. Observing no actionable anomalies, the engine and motorcycle were cleaned, reassembled with new head gasket, cam chain adjuster gasket, oil port o-ring seals, and valve cover gasket.
Two re-assembly problem did occur. The rear head bolt could not be tightened to its full specified torque (tapped receiving hole stripped) and the upper mounting bolt securing the cam chain adjuster housing to the engine block could not be tightened to full torque specification (tapped receiving hole stripped).
Following full reassembly of the cycle, the bike [cold] started easily and ran smoothly at idle and higher engine rpm (up to 3500 rpm). Within 4 minutes of start-up and idle (1100 rpm) harsh-smelling smoke began coming from the engine area (again I was unable to locate/pin point a specific source). The bike promptly stalled out. I was able to restart the cycle but I could only keep it running by increasing the throttle to cause the engine to run at 2500+ rpm. Holding the engine speed at 2500 rpm resulted in increasing amounts of bluish hot-smelling smoke and even momentarily releasing the hand throttle caused the cycle to stall. The hot engine would not now be turned over by the starter. Blowing cold air over the engine and drive-train metal housing [accelerated cooling] enabled restart. Very soon thereafter the same behaviors were experienced (hot excessive smoking from the engine area...the cycle would not run at idle, and the starter would not successfully turn over the engine nor start it while the engine was hot and smoking. There did not appear to be any difference in the quantity or composition of the smoke this time compared to the first trial run.
Approximately one week later, my brother hand-pushed the cycle to a different shop location. He reported that it took an inordinate amount of force on the hand clutch lever to disengage the clutch (requiring 4 fingers and full hand squeeze effort). I do not remember trying to operate the clutch lever during the trial run following reassembly of the engine... so I do not know if that anomaly existed at that time.
HELP...SUGGESTIONS...SOLUTIONS...REPAIR RECOMMENDATIONS ... or R.I.P.
To be honest, I am uncertain what is causing all the problems. Would a failed clutch account for all these symptoms? Have any of you encountered similar problems/symptoms? How did you resolve/repair the problem? How (gulp) expensive was the solution (if you found a solution)? I do like the cycle; but I am on a tight fixed budget (disabled) and if the cost of repairs exceeds the value... <sigh>...
Has anyone had experience with removal and then installation of a rebuilt block/engine and/or clutch? Is it practical from a $ point of view? I have had some experience working on engines...but never before on a motorcycle engine/drive train. Any advice, shared experience(s), diagnosis, prognosis, recommendations will be sincerely appreciated.
Thank you,
Bob Michaels
Madison, WI
lustt@charter.net
AnswerHi Bob,
That was the most detailed (and longest) narrative I've ever received. Good job!
There a problem with compression on cylinder #2. Can you perform a leak-down test? I would need to know the results before offering a dianosis.
If the clutch lever felt normal prior to engine removal, I suspect the lever problem is related to reassembly. Maybe routing or binding of the cable or linkage.
I use Dr. Scholl's Foot Powder Spray for oil leak detection. The spray is expensive; about $7 a small can. The spray goes on pure white and dries to a fine powder that won't blow away in the wind. Oil bleeds through dark brown making small leaks easy to find. When done, the powder cleans off easily.
Need to do the leak-down to determine what parts are worn or broken. We can go from there.
I'll send some test/repair files to your email addy.
Respectfully,
Mark Shively
Dayton, Ohio
