Yes, Mike, the first time I performed the cylinder leakdown testing, Summer 2016, the leakdown % numbers were so low on my 1975 GL1000's cylinder #1 that I was suspicious whether my tester, a regulated single pressure gauge unit that Kohler Engines sold from their Service Tools catalog, was still working correctly. 20ish years ago, its accuracy tested surprisingly close to a dual gauge Snap-On leakdown tester. ( ~5% leak rate consistently displayed, 2 years ago, in all 4 cylinders was quite surprising.)
Enough so, that I nudged the kick start lever to rotate the crankshaft sufficiently to allow the applied air pressure (100psi, regulated ) to dynamically force the piston towards bottom dead center. When the T1 timing mark suddenly disappeared from the "window", I was relieved when the exposed left side camshaft pulley closest to me displayed continuing rotation, and the tester's pressure gauge reading immediately dropped to zero, expelling the still flowing air supply into the exhaust system.. I know there will always be, even at the very best internal conditions, air leakage into the crankcase past the piston ring end gaps, but have no idea what those ring end gap dimensions are. Apparently very small!
Since I became so invested in the "Yet another Compression Testing topic", and as a consequence, this one, too, my interest in having the best equipment for this investigation purpose has increased. Even though I have a Snap-On 250psi maximum cylinder compression tester gauge set-up, it's old, and I don't have complete confidence that the sealing oring on the 12mm adaptor is up to snuff, nor adequate for testing accuracy. I'm working on producing an adaptor, made from a 12mm NGK spark plug, that can be tightened with a wrench, to seal against the cylinder head with its already compressed, metallic gasket.
With the wealth of information I'm gleaning here, my being satisfied with fairly consistent 140ish psi cylinder compression tested numbers no longer suffices when trying to make my trike's engine perform as well as it should.
Several months ago, I was the old cat (68
) that had expressed that I would like you to ride my trike and tell me how the engine behaved in your estimation. With a "modified" exhaust system. Simply, a slightly angled, 1 3/4" OD straight pipe off the header outlet, into a 1 3/4" inlet H-D Softail muffler.
But, we're 3,000 miles distant. Exhaust constipation, has always been a concern, but how can I get best overall engine performance AND fuel mileage numbers, without deafening myself and unduly annoying others? The tip of the twin mufflers extends beyond the rear axle centerline. Why so long? I found from previous experience with my CB900 Custom trike with a Slipstreamer windshield installed, that the air circulation off the fairing, draws exhaust gas back into my riding space.
CO headaches are a very real threat.
Last week, before my first time out this year, I had removed the H-D Softail catalyst mufflers, and installed a set of new Rush 1.75" baffle mufflers. Overwhelmingly loud, but seemingly better engine performance behavior was presenting. Surprisingly, the Route 81 Interstate speeds' fuel consumption rate, averaged over 330 miles, at 4,300-4,900 rpm range, ~65-75 GPS confirmed mph, when compared to similar operating speeds last Fall with the catalyst mufflers installed, has actually increased, 3-4 mpg to ~31 mpg. The very best fuel mileage average had never exceeded 30mpg , at an average speed of 60mph, at 4,000 rpms, prior to that change of mufflers this first time out. A GPS displayed 80mph, at 5,200rpm, shows the stock GL1000 speedometer, itself, displays ~2-3 mph, fast. Difficult to hold my cell phone and compare numbers.
I have to get trike weighed sometime, but would estimate that, conservatively, 850 lbs with sporting a Pacifico fairing, too, reduces averaged fuel mileage expectations, drastically. Plus, my 220 lbs, in addition puts it and I over 1,000 lbs....
BTW, The trike's GM 8.5 inch rear axle ratio is 3.73 to one.
The Continental 215/60-16 tire diameter, 26.1 inches is close to the standard tire dimension that was previously installed sometime before I bought the original configuration '75 GL1000, with 7,831 on the odometer. What appeared to be Jardine downturn mufflers were in place, too. NOISY!
Another 25,333 miles has been accumulated on the odometer since trikification, in 2012.
Without having a stock configuration exhaust system to install and have an exhaust sound/engine performance standard to compare my modified system to, I feel that I'm getting to the point where the realistic expectations are getting closer to optimal for my trike, and me, too!
Thank you, VERY MUCH, Mike!
