Five must-haves for a good-running GL1000

Tips and Recommendations from Guru Mike Nixon

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desertrefugee
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Re: Five must-haves for a good-running GL1000

Post #31 by desertrefugee » Wed May 02, 2018 6:29 pm

mikenixon wrote:Took this reading today on the CBX engine I am fettling. Corrected for altitude it becomes 213 psi. Complete top end repair including Wiseco 1147 kit.


lol. Great usage of the British term for "putzing". I've been perusing a few of the great British classic bike magazines lately. Makes me miss the old days when we here in the states had some more down-to-earth enthusiast rags.

I'd love to hear that one run with that kind of compression. The kind of compression that'll blow your hat off standing behind the pipes when it's running.

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Re: Five must-haves for a good-running GL1000

Post #32 by mikenixon » Sun May 06, 2018 4:46 pm

desertrefugee wrote:
mikenixon wrote:Took this reading today on the CBX engine I am fettling. Corrected for altitude it becomes 213 psi. Complete top end repair including Wiseco 1147 kit.


lol. Great usage of the British term for "putzing". I've been perusing a few of the great British classic bike magazines lately. Makes me miss the old days when we here in the states had some more down-to-earth enthusiast rags.

I'd love to hear that one run with that kind of compression. The kind of compression that'll blow your hat off standing behind the pipes when it's running.


Actually, I'm using the word "fettled" in the same way I have observed it being used in the repair industry, especially by our Brit cousins, in the sense of "massaging" or "TLC" or "putting things right through careful professional attention." :)
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Re: Five must-haves for a good-running GL1000

Post #33 by mikenixon » Sun May 06, 2018 5:38 pm

Image

This drawing (mine) from my website, specifically from the article on lobe centers, is the whole picture from which I sketched the simple red and blue sine curves previously. It shows what I have been calling the vertical and horizontal dimensions. Vertical of course is the valve's open amount, horizontal the valve's open time.

This picture and the process of making it is often called a "cam profile". A full profile such as this is rarely necessary or even helpful. It serves the theoretician much more than the technician. What techs do is plot only the opening and closing numbers, lift amount if messing with non-stock cams and having to deal with spring issues and other clearance considerations, and speaking of clearances, we at this time want more than anything else to test for valve-to-piston clearance through a range of crankshaft positions centering around TDC overlap, the tightest spot in the four-stroke cycle.

The opening and closings give us reference to what Mother Honda says should be happening, cam timing wise. It is not uncommon to see a cam retarded up to 10 degrees, through wear of both the cam and its chain (and less so, belt). The tech focuses on the intake opening number most of all as it will tune the engine. An earlier opening will move the powerband lower in the rpm range, causing torque to peak sooner. A later opening does the reverse, pushing the peak torque point higher in the rpm range.

The max opening ("lift") measurement is taken and used in redesigning/managing springs and lifters.

Valve-to-piston measurements warn or encourage that the engine will not or will live with modified cams or other parts. They also tell us if more power can be safely had mechanically through compression increases.

Note the lobe center indications. Though many see lobe center as a tuning function, that is not its correct use. It originated and is legitimately used as a camshaft comparison tool, that is, it is the most meaningful and consistent way to compare two cams with each other. Tuning is instead much more simply effected by intake opening, as mentioned above. See my article on lobe centers. In a way, this is largely semantics. Anyone who goes to the trouble of determining lobe center already knows intake opening because you have to have that to get lobe center. :)

The dashed line shows that valve opening and closing must not be measured as soon as the indicator needle moves. Instead, several thousandths of an inch are "given away" to get the valve off the cam's most gradual point so the reading is more accurate and consistent.
Mike Nixon
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Re: Five must-haves for a good-running GL1000

Post #34 by mikenixon » Sun May 13, 2018 5:59 pm

mikenixon wrote:Image

Edited for spelling and clarity.

This drawing (mine) from my website, specifically from the article on lobe centers, is the whole picture from which I sketched the simple red and blue sine curves previously. It shows what I have been calling the vertical and horizontal dimensions. Vertical of course is the valve's open amount, horizontal the valve's open time.

This picture and the process of making it is often called a "cam profile". A full profile such as this is rarely necessary or even helpful. It serves the theoretician much more than the technician. What techs do is plot only the opening and closing numbers, lift amount if messing with non-stock cams and having to deal with spring issues and other clearance considerations, and speaking of clearances, we at this time want more than anything else to test for valve-to-piston clearance through a range of crankshaft positions centering around TDC overlap, the tightest spot in the four-stroke cycle.

The opening and closings give us reference to what Mother Honda says should be happening, cam timing wise. It is not uncommon to see a cam retarded up to 10 degrees, through wear of both the cam and its chain (and less so, belt). The tech focuses on the intake opening number most of all as it will tune the engine. An earlier opening will move the powerband lower in the rpm range, causing torque to peak sooner. A later opening does the reverse, pushing the peak torque point higher in the rpm range.

The max opening ("lift") measurement is taken and used in redesigning/managing springs and lifters.

Valve-to-piston measurements warn or encourage that the engine will not or will live with modified cams or other parts. They also tell us if more power can be safely had mechanically through compression increases.

Note the lobe center indications. Though many see lobe center as a tuning function, that is not its correct use. At least not in a perfect world. The lobe center procedure originated and is most legitimately used as a camshaft comparison tool, that is, it is the most meaningful and consistent way to compare two cams with each other. Tuning is instead much more simply effected by intake opening, as mentioned above. See my article on lobe centers. In a way, this is largely semantics. Anyone who goes to the trouble of determining lobe center already knows intake opening because you have to have that to get lobe center. :) And, if two people having the same cam but using different check heights are degreeing their cams, the only way to get them to agree will be through using the lobe center method of timing. The beauty (and whole point) of lobe center is to eliminate the need for only one consistent check height. Using lobe center, ten different check heights used on identical cams will yield identical numbers. Because, the center of a thing is always the center, no matter how much you shave off its two ends. :)

The dashed line shows that valve opening and closing must not be measured as soon as the indicator needle moves. Instead, several thousandths of an inch are "given away" to get the valve off the cam's most gradual point so the reading is more accurate and consistent.
Mike Nixon
www.motorcycleproject.com

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Re: Five must-haves for a good-running GL1000

Post #35 by gltriker » Fri May 18, 2018 12:00 am

mikenixon wrote:Hi, gltriker. No, no bad effects, no fallout. The experience of mechanics everywhere confirms this. Not only is not harmful, it will gain you at least 10 psi and possibly 20 psi cylinder compression per cylinder. And the carbs, as I say, will work better, because they will get a stronger signal. They actually richen slightly.
As for accelerated valve wear, no. The 0.002" is invisible vertically. It's horizontally that makes the difference.


Hello, Mike! Please, be patient while I add some observations to your Topic. I am long-winded. Keep in mind this 1975 GL1000 engine has a nicely functioning, unmolested set of 1976 carburetors installed, and stock air filter housing and OEM Honda air filter element.

I'd already reported, several weeks ago, that I had reset the trike's intake and exhaust valves' clearance gap to 0.006". Since doing that seemingly little thing, several weeks ago, I have put, at least, an additional 900 miles on its odometer. Although those valve gap clearances were increased by 0.002", I haven't retested the individual cylinder compression results, yet. Eventually, I will. ;)

Seems that small valve clearance gap increase, has unexpectedly presented measurable benefits that ties in with your statements I have highlighted above, in blue.

I am very surprised, and pleased, that my trike's engine fuel mpg has increased, too! Honest! No exaggerations.....none!

Prior to my getting very interested/invested this Spring, after 25,000 trikified miles, with understanding how the change to the 'lower' final drive gear ratio, with a highly modified GM 3.73 to 1 rear axle assembly, and the exhaust system modification were affecting trike's engine performance, I had always utilized the number of miles that had elapsed on the trip odometer since the last fill-up, when it became necessary to flip the fuel tank petcock lever to its 'Reserve' position.

For the first 3 trikified years , (2013 - 2015) 117-119 miles was the typical trip odometer distance displayed at the time petcock lever flipover was necessary. Then, guestimating I could reasonably expect 4 gallons of fuel had been consumed, I accepted 29-30mpg would be the answer. During those first 3 years', 15,000 miles, my maximum speed was rarely faster than 60mph. true 60mph = 4,000rpm.
As I gradually became more confident in my trike's operational integrity, and my ability to operate it safely at higher sustained speeds, the average mpg at the higher engine speeds seemed, of course, to diminish a little.

In my 2016 quest to reduce exhaust system noise, after the first 15,000 miles elapsed, I replaced the H-D tapered mufflers (eBay) with H-D slash-cut units (eBay). When I discovered they were Catalyst mufflers, I envisioned only the worst. Not so. At that time, I reported, they woke the engine up! I always thought I was pushing my luck, though, if I attempted to ride more than 145 miles before filling the fuel tank again.
Coming back from the Canadian Rally last September, 2017, trike ran completely of fuel about 100 feet from my driveway. A few miles less than 150 miles was delivered on a full tank of fuel.
But, in addition to the conservative group riding speeds of 55mph in Canada, after crossing the Border into the US, I had run down the Interstate for 70 miles, at an average, sustained 75mph at approximately 5,000rpm.

Anyway, since removing the horrendously loud Rush mufflers I'd installed first thing this year, and re-installing the Catalyst mufflers that I'd voiced concerns about in the not-too-distant past, I've utilized a more precise method to calculate mpg now, as well.
But, I still adhere to the, let's see how many miles I ride until the fuel petcock lever has to be repositioned to 'Reserve'.

A week ago, it starved for fuel at 131 miles on the trip odometer. :shock:
This afternoon, 130 miles elapsed on the trip odometer.
26 miles later, I refilled the fuel tank this afternoon with 156 miles displayed on the trip odometer. The pump displayed 4.751 gallons of 87 octane gasoline was dispensed. Smart phone calculator results were 32.8 mpg. action1
Most times, since the valve clearance gap was increased, the flip to Reserve event averages around 123-125 miles on the trip odometer.
Still, it's better than the previous best standard of 117-119 miles.

Seems as though I can actually detect a difference in overall engine performance with some fresh fuel fill-ups, too.

THANK YOU VERY MUCH, Mr. MIKE NIXON! :oldies tumb2

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Re: Five must-haves for a good-running GL1000

Post #36 by ericheath » Fri May 18, 2018 10:07 am

“The pump displayed 4.751 gallons of 87 octane gasoline was dispensed.”

Haha, we’d get along fine Cliff. A good quart left in the tank PLUS 4oz in the bowls. You had a solid nine miles left. ( not counting coasting down hill)

I’m checking my clearances today.

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Re: Five must-haves for a good-running GL1000

Post #37 by mikenixon » Sat May 19, 2018 8:30 pm

Yes. Higher efficiency via added cylinder compression. And lest someone call my statement re richer running contradictory, consider that the engine runs better with more compression (less fuel waste), so needs less fuel, making the engine "see" the existing carburetion as excessive, i.e., rich. It doesn't mean the carbs are actually richer. The engine-to-carb relationship is richened, if that makes sense. In addition, more engine efficiciency results in less throttle opening required for the same power. It's the nearest thing to a free lunch. And as I've said before, us lowly mechanics have known of this and practiced it for nearly a hundred years. :)
Mike Nixon
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