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So, I can only get 85 mph out of my 1980 CX500. Any tips out there on how to get better performance out of her. I'm new at this stuff, so any help is much appreciated.
 

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So, I can only get 85 mph out of my 1980 CX500. Any tips out there on how to get better performance out of her. I'm new at this stuff, so any help is much appreciated.
It sounds like you might have some carb-related problems. A general tune-up and carb cleaning should do wonders.
 

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Yep, carb o/haul will do it wonders. You'll think it's a different bike.
 

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Could also be your cdi box. Had that happen on mine full throttle and she just wouldn't go faster than 80. Changed my cdi and then she would run up to 120.
 

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Could also be your cdi box. Had that happen on mine full throttle and she just wouldn't go faster than 80. Changed my cdi and then she would run up to 120.
does your 1979 500 really do 120mph
 

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What runs thru my mind when I read that is: How do you know you were going 120mph when our speedos only go up to 85mph ? Or did you have an aftermarket speedo on it ?
and what does the rev. counter show at 120.........
 

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I've got the factory 120 speedo on mine and as much weight as I've lost due to my illness that I haven't gained back I'm sure I could probably hit the redline in 5th with the StreetShields windshield on the front. They all differ, but I think most max out between 108 - 112.



I don't mind driving around 95 in my car which is often the going rate down I-35 in certain parts of Texas but I wouldn't feel comfortable driving the bike at that speed. I took that Yamaha 650 Maxim (modified cam) I had for a while up to around 140 one time and it wanted to go faster but the world turned into a blur. I don't like going over 75 on my bike and prefer less, even if I've got to move over to the right to let the cars go by.
 

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Between 70-75 is about as fast as I ever go on mine as well.....it just works the engine too hard to go much faster IMO.



That being said IF you're truly going 125mph would you not be constantly red-lining the tach which you should NOT do ? Isn't that why the red-line is there so that you do not exceed that point ?
 

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Redline is 104. He would need more mods than to get higher. Maybe just maybe I could break the 110 mark with the 650 clutch and primary gear upgrade but i'm not going to test it.



If you want a sportsbike buy a sportsbike. I wish I still had my 1979 120mph speedometer. Sure I don't break 85 much but it seemed to be right in line with the tach so the needles matched in 5th gear.
 

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During the first few months after I purchased my GL650 I gradually rode longer distances until I was confident about commuting to work every day on the machine. There were 2 routes for me to travel. One was on a multi-lane highway and one was a two-lane state road. I got bold on the big highway and opened the throttle and scared myself. I felt naked as I watched the concrete rush by and the felt wind whistling around me. So most days I rode the smaller state road which capped my top speed at 55. A few months of this and while I was returning home one evening the highway patrol pulled me over. He clocked me at 73 mph in his radar. I pulled off my helmet, exposing my bald spot and greying hair, then replied, "Are you sure? Because I was up to 75 mph on the other road and it scared me to death." I expressed amazement that I could be traveling at 73 mph and not feel the anxiety from that speed. He said, "Well, get your speedometer calibrated and watch yourself more carefully." My ONCE-IN-A-LIFETIME narrow escape from a ticket . . . or . . . the benefit of losing hair and turning grey.
 

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Could also be your cdi box. Had that happen on mine full throttle and she just wouldn't go faster than 80. Changed my cdi and then she would run up to 120.
All the original test articles I've ever read have the top max speed at 100-105 mph, depending on the model and year.









What runs thru my mind when I read that is:  How do you know you were going 120mph when our speedos only go up to 85mph ?   Or did you have an aftermarket speedo on it ?
The older speedos have the higher mph readings on them, my original 79's was one of those.  I replaced it with an 85 mph one supposedly from an 81, maybe they switched in the 80's?
 

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If I recall only the '78 and '79 came with 120s, after that it was 85 mph. Bike wasn't any different so it was kind of a stupid change. If you can find a 120 or even a 160 it'll work, even if off a different Honda, Yamaha or Kawasaki.
 

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and what does the rev. counter show at 120.........
The speedo was broken when I got the bike. I swapped it for one off of a 1980 model. The tach was redlined plus some. My buddy bet I couldn't get the bike over to do over 100mph. I took him up on it and he paced me on his cbr600rr. Both of our spe

edos were reading 120mph. I also won $200 that day.
 

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Power to weight ratio. Best bang for your buck. The easiest way to shave 20 pounds off of your bike is a combination of pipe and rider. The truth hurts. We need to lose weight to be faster, just ask those GP guys.
 

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My brand new 79 Custom had the obligatory 500 miles break-in time, new tires, a 120 speedo, and a long, Texas road down by Kingsville. My buddy Alan had a brand new Mazda RX7 and we were running the same speed, and he said his speedo indicated 125. It was the one time, and never again!
 

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I smell a load. I know what these bikes can do and you do to but someones been fishing. If the bike redlines around 104mph then that's what you get.



If these bikes could naturally go 120 mph then we would know that and our salt flats record holder would have wasted a lot of time trying to make a bike that would beat the record of 111mph. Just to get at a 123mph average.



http://www.northbaysportriders.com/forums/index.php?showtopic=12572
 
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