85 should be easy for a CX

My less then perfect example with barn door windscreen will do 85 easily

enough so maybe your motor needs some attention?

You should be able to cruise at 70-80 with the bike feeling 'busy' but not strained

rpm should be about 7000 at 80.

As to the top speed. Well like MPG, thats subject to all sorts of variables and fantasy

 

I can peg out the speedo in 4th on my GL, toss it into 5th and the whole thing starts to get light and floaty as it winds out to redline.

 

Top speed is 104mph. Depending on the mods done you can get a hair more out of it but not much.

 

+1



I've had mine to an indicated 106mph on a long straight of an empty 4 lane. I know the my speedo reads 5-10 mph high.

 

I've had 107 Mph on one of mine but that's on the speedo so will be incorrect.A well serviced CX/GL should be able to do a ton but I wouldn't recommend it for long periods with the old metal in these engines.



As Reg says they can sit at 70/80 all day long and be happy.I came back from a ride-out using Motorways/Interstates for around an hour and a half doing between 65 to 90 for,"Combat speed" and the bike/s have performed great alongside some very modern bigger bikes

My 10 penn'th

 

I snapped a crank going too fast for too long on a bike which the day

before had won the 'best sounding engine' prize at a rally

Ouch! pride before the fall and all that.

I have never tested the top speed on this one, if I want to ride at triple figures

I use the beemer.

This one feels happy cruising at 6-7 thou and I tend keep it around there with occasional

breif forays up to a little over 8K just to blow the cobwebs out.

In this vid I reached about 90 ( 8000 at 1:24) quite easily.

Notice it 'shimmy' as I cross the white lines at 70-80, thats another reason I dont push it much.



[media]http://www.youtube.com/watch?v=WmTfePCHOPw[/media]

 

I dig the air freshener Reg!

 

Now when you say you got it together enough to take it out, does that mean you've made mods like open exhaust? Open air cleaners? Have the jets been changed? Carbs adjusted and vacuum balanced? These all could affect it

 

Cripes Reg! Your riding on the wrong side of the road! Then passing on the right! What's wrong with you guys? How do you manage that? Do your signal lights work opposite of ours too? No wonder gas costs so much over there.

 

Naw, it looks like someone put the film in backwards when they put it in the projector. Emulsion side down next time.



The CX will cruise at 100-105 with no problems, so there is something limiting your bike. Start with the simple stuff, fuel supply. Make sure the in tank screen is in place and not partially blocked. Check you lines, inside diameter especially, there are plenty of hoses out there which have identical OD's but small ID's (high pressure fuelish injection and hydraulic lines) etc.



Plug caps, remove resistors with solid stock.



Keep us posted on what/if you find anything to explain your lack of top speed.

 

My 500 will easiliy go over an indicated 100mph but I guess these old clocks are wildy inaccurate. Whilst following Reg to a rally on his beemer on one stretch I had the 650 hard on the stop !! Dam near lost my air freshener

 

108 just to see what to what it could do . 70-80 is fine for me, even less depeding on traffic.

 

In order to hit top speed on any bike it has to be running nearly perfect. Previous posts mentioned tuning and I will second that. Your bike sounds like it is running about 15 to 20 slow. I would start with a compression check, then valves, plugs, timing, and carbs. Boise is about 2700 foot altitude so you are losing some horsepower there, but not that much. You could have some jetting issues that are not allowing you to pull high rpm under load in 5th. Also, you're a big guy and you will really have to get snug on the bike to reach top speed. If you have a jacket flapping around, it is essentially a parachute, so tuck it all in. Next time out see what the max rpm is in 5th.

 

Also, you're a big guy and you will really have to get snug on the bike to reach top speed. If you have a jacket flapping around, it is essentially a parachute, so tuck it all in. Next time out see what the max rpm is in 5th.

Good point. I should mention that I'm 160 lbs, and I was in a full tuck when I hit 106 mph indicated. And I've clocked my bike with a GPS... so I know my actual was more like 98 mph -- and it's state of tune is not 100%.

 

I haven't had this new engine very fast. I did get it to 9500 rpm in 5th once. Since my speedo stops at 85 I don't know how fast I went. Passing usually ends up at 85mph before I can lean back into my lane.

 

A fairly close estimate of your top speed would be to see how many rpm you can pull and then check your speed at half the rpm. If you can hit 9000 and the speedo is obviously at 85 or in the blank, then see what your speed is at 4500- maybe 55mph. Double that and you have an "indicated" 110 at 9000rpm. Of course we have the error to allow for but that should at least give you a comparison to see if things are working or not.

 

Mine never goes over 85, at least according to the speedo. My original speedo indicated up to 105 or 110, I forget which, but my new, post 70's oil crisis speedo only has 80 plus a hash mark.

 

I've only taken mine up "to the Ton" a few times. They will do it, but they have to be right.

If you changed exhaust or air box from stock, then you have to rejet the carbs. A stock set up with loose valves, and unadjusted timing chain , old tires, weak gas will not run up to 100.

I don't know the state of tune on your ride, but with more work it will run up there. It sure is busy on one of these at 100+.....

 

Don't know my top speed, I peg the speedometer at 85 at around 7k-7500 rpms, and just the other day had it clear to 9800 or so, just under 10k on my CX500C, only mod I have it straight pipe exhaust, and haven't adjusted the jets to match, and carbs aren't balanced either

 

is 90 honestly not fast enough for you on a death machine?? these arent crotch rockets nor do they handle like one

 

Mine was smooth as silk at 100+.

I wouldn't want to be carving corners on the CX at that speed... but in a straight line, it was rock solid.

 

Bike mag tests (from the era) that I´ve read, tell about true speeds of just under 170 kph (105 mph) up to 185 (Das Motorrad (Germany)). 185 would mean exceeding redline in fifth - in fact just over 10000. I´ve never seen that (or had the guts to try hard) but my black one (with a fullsize windscreen) once (windstill) let me see a bit more than 9000 (9400 or so) on the tacho in fifth and still had more... Ran out of guts.. Speedo just over 180 kph.



I don´t think of CX 500 as a totally steady bike at speed. Light waveing is what I expect to run into - and normally I don´t get disappointed...



Sture

 

in my opinion,anyone who pushes a 30 year old 500 motor close up to,or over,100 mph needs 2 things.....

1/a talking to

and

2/e bay

 

Okay, so based on all the aforementioned talk of speeds and RPMS, on my 1978 CX500 I'm hitting about 5,850 RPM at 65mph, is that 'in spec', would you think?



Sometimes it feels a little 'sluggish' like it doesn't want to go above 65 mph at wide-open throttle, but other times I can get it up to, oh, 70 mph or so and still feel like I have some more 'room to grow' before I start having visions of the cam-chain bolt rattling out into the engine at speed and I back off, or a curve comes up...and I too can't imagine snapping into a curve with a bike as top-heavy as this one is; talk about high-siding!



Don't get me wrong: I love the bike; but are my readings right??



John

 

They sound fine to me.As for the sluggishness it could be carbs/plugs/Ignition.As you most likely know losing a few pounds would help a lot.I've got about a stone to lose as I always put some on in the Dark months.I'm around 190 but usually get down to 175 lbs for the season

And with fuel prices as they are,especially over here,every pound off is some more fuel in the tank

 

What?? It's not a beer belly...it's an Investment!

I'm 6'1" and (last time I looked) 220lbs; so yeah, *I* might have something to do with it, but I doubt it...and I probably AM due for a plug cleaning...I'll start with the simple stuff first.



Yeah, I agree: I thoughtgas was expensive over Here until I saw what you guys are shelling out PER LITRE! It makes us sound like a bunch of whiny..well..Americans!

 

I'm bumping this thread so I don't have to start another.



I've been playing with trying to figure out the top speed of my bike lately using the GPS on my cell phone. Seems to me like it doesn't want to go any faster than 96MPH.



Yesterday I was on a long, flat, straight road and decided to test top speed. I was tucked down, and was holding my throttle way open and in fifth gear of course the speedo was pegged out, but my RPMs stopped at 8000. They just wouldn't climb any higher. I tried doing this again several times, rolling on in fifth, or accelerating up in fourth. But when trying for top speed, it just won't rev any higher than 8000 RPMs in the fifth gear.



The bike also wants to idle a lot slower after riding at rather high speeds, usually if I'm riding it around 80 MPH for a while. On top of that, my 0-60 is only about 7 seconds. Feels like the clutch is slipping in first and second, but I may not be revving it enough.



I'm chasing other engine gremlins that are soon to be taken care of, but I wonder what the forum's take on this particular issue is. I've never heard of a bike being unable to surpass a certain RPM like that when doing a high speed run...so some explanation would be much obliged. Of course, I'm a noob to the mechanical aspects of bikes, but I asked a mechanic friend of mine and he as well said that he doesn't have a clue why it wouldn't rev past 8000, and that the idle getting slower as the engine got hotter was especially strange.



Oh, and at the very least, I don't think it should be blamed on fuel. I run 87 regular normally, but I found a gas station in the middle of nowhere that was selling 90 grade with NO ethanol. I noticed no performance changes, but my gas mileage increased a very good amount.

 

I'm bumping this thread so I don't have to start another.



I've been playing with trying to figure out the top speed of my bike lately using the GPS on my cell phone. Seems to me like it doesn't want to go any faster than 96MPH.



Yesterday I was on a long, flat, straight road and decided to test top speed. I was tucked down, and was holding my throttle way open and in fifth gear of course the speedo was pegged out, but my RPMs stopped at 8000. They just wouldn't climb any higher. I tried doing this again several times, rolling on in fifth, or accelerating up in fourth. But when trying for top speed, it just won't rev any higher than 8000 RPMs in the fifth gear.

The bike also wants to idle a lot slower after riding at rather high speeds, usually if I'm riding it around 80 MPH for a while. On top of that, my 0-60 is only about 7 seconds. Feels like the clutch is slipping in first and second, but I may not be revving it enough.



I'm chasing other engine gremlins that are soon to be taken care of, but I wonder what the forum's take on this particular issue is. I've never heard of a bike being unable to surpass a certain RPM like that when doing a high speed run...so some explanation would be much obliged. Of course, I'm a noob to the mechanical aspects of bikes, but I asked a mechanic friend of mine and he as well said that he doesn't have a clue why it wouldn't rev past 8000, and that the idle getting slower as the engine got hotter was especially strange.

Oh, and at the very least, I don't think it should be blamed on fuel. I run 87 regular normally, but I found a gas station in the middle of nowhere that was selling 90 grade with NO ethanol. I noticed no performance changes, but my gas mileage increased a very good amount.

Hello, you hit top end. Unless you're saying that you can pull in the clutch in 5th gear & the engine still won't rev past 8k. When the mechanical, gravitational and aero resistance matches the horsepower produced, speed no longer increases. Regardless of the redline or the biggest number on the speedo.



It sounds like your mechanic friend is also "a noob to the mechanical aspects of bikes". An honest 96mph is not too far off on a well-used CX500. FWIW, most vehicles will not pull redline in top gear. Many newer vehicles have speed limiters, but there is no electronic speed limiter on the old CX/GL's. Just old-fashioned physics.

 

I always run premium, and have hit the redline in 5th several times, running iridium NGK's. I'm about 140 lbs or so. I don't know my 0-60 mph, but I know that I run 1/4 mile in 14.8-14.9 with saddle bags fully loaded with parts books, rain gear, work shoes, and luggage rack with trunk also fully loaded, was on the way home from work when I decided to hit the drag strip.



Your clutch shouldn't slip unless you're revving it high and dumping it, at the track I'll hit 6500 and dump it, laying on the tank to keep the front wheel down, for the most part, and it slips for a second, but when it grips, it GRIPS, but other than that, it shouldn't slip. You should be able to go from no throttle to full throttle any time with no slippage, if it does slip, either it just needs to be adjusted, or it's starting to go out.

 

First thing I would do is make sure when you are W.O.T. the carb throttle is actually wide open,,if the cable was not adjusted properly you may not be getting full throttle. Hold the grip wide open with the engine off, and see if you can move the linkage at the carb to open the butterflies more.

 

Being new to engines, I'm unsure if the clutch is really slipping or if it's something else...but it's most noticeable when I'm giving it tons of gas, and it feels like it isn't "gripping" completely for the first second or so. I don't think I ever notice it while revving and not shifting gears, so it may not truly be clutch slippage. I can describe the feeling as "notchy" a lot of the times, even if I've already finished shifting and I'm not touching the clutch. Uncertain if it's related or not.



As for the throttle cable...good call. I'll check that. I do know that a moto-guru friend of mine who's ridden the bike said that the throttle is "way too sensitive...either you're engine braking, or you're accelerating, and that's why the bike is acting up in the twisties." He went on to say that he thinks it's to blame on the CV carbs, but I'm not too sure that they're supposed to be that "notchy."