Author Topic: Almost Ton Up? (Read 5649 times)

gregwaits · « **on:** May 22, 2008, 04:52:06 PM »

I was driving the cb750 to a rehearsal last night (yes, with my trombone on my back). Traffic was light and visibility was excellent. Well, one thing led to another and I started leaning into it and squeezing more speed out of the bike.

I was sailing along at near 90 mph and I assumed that there was no more to be had. Hell, I weigh 220 lbs --and I had a gig bag strapped across my shoulders.

I tucked way in and pulled back the throttle a bit more, and HOLY SHYTE the bike did have more to bring to the plate!

In no time at all I was inching towards triple digits. I would have been there in a matter of seconds had my common sense (??) kick in. I was fast approaching other cars on the freeway and I figured I'd be better off with a little less speed, so I dialed it back.

All said, the bike tracked phenomenally at that speed.

Damn, I backed off at 97 mph!

Ecosse · « **Reply #1 on:** May 22, 2008, 05:03:51 PM »

Sooo that's the secret?! Musical instruments are effective aerodynamic aids!

If Hailwood only knew.

mlinder · « **Reply #2 on:** May 22, 2008, 05:04:37 PM »

I've had mine at 120+.
Glad you backed off in traffic though. Triple digits can do weird things to your perceptions if you aren't used to it. Perception being off at triple digits can be painful

nilsey · « **Reply #3 on:** May 22, 2008, 05:39:34 PM »

not to doubt you too much....

but i know from experience in my old datsun 280z that speedometers are not very accurate at higher speeds, so this is a general question to the forum: how accurate are our sohc honda speedos generally?

mystic_1 · « **Reply #4 on:** May 22, 2008, 06:56:32 PM »

Excellent question.

mystic_1

ChippK8 · « **Reply #5 on:** May 22, 2008, 07:08:14 PM »

Quote from: nilsey on May 22, 2008, 05:39:34 PM

not to doubt you too much....

but i know from experience in my old datsun 280z that speedometers are not very accurate at higher speeds, so this is a general question to the forum: how accurate are our sohc honda speedos generally?

I know at low speed mine is about 5 miles faster than my speed. One of those radar gun trailers that tell you how fast you are going was setup by my house and I noticed.

jtb · « **Reply #6 on:** May 22, 2008, 07:24:51 PM »

Quote from: nilsey on May 22, 2008, 05:39:34 PM

not to doubt you too much....

but i know from experience in my old datsun 280z that speedometers are not very accurate at higher speeds, so this is a general question to the forum: how accurate are our sohc honda speedos generally?

When the speedo says 97, it's fast.

BobbyR · « **Reply #7 on:** May 22, 2008, 07:34:22 PM »

I would say that you hold the SOHC record for speed with a Trombone strapped to you back! I would say that record will stand for quite a while.

super pasty white guy · « **Reply #8 on:** May 22, 2008, 07:42:37 PM »

I have 2 sets of speedos. The one that came with the bike wasn't original, but was dead on according to those radar trailers. The other (bought as a temporary while I finish the gauge face refurbish) was off by 10-15 when I installed it but has since gotten more accurate and is off by 5. I don't know how long I was exceeding the limit by a substantial margin (usual traffic is 10-15 over, plus a 10 mph error in gauges...).

Now that I've switched to a 18-48 ratio from the po's 16-48 I've got more problems staying legal. I find myself at "highway vibration level" which is suddenly 10+ mph higher than it used to be.

spwg

bunghole · « **Reply #9 on:** May 22, 2008, 07:42:55 PM »

Checking Ebay for trombones right now!

markjenn · « **Reply #10 on:** May 22, 2008, 07:59:17 PM »

Typical speedo error is 5-7% high and although I haven't checked it precisely on my K1, that sounds about right.

I put a new speedo face on on of my everyday bikes (a Strom) that had been corrected for speedo error (and checks out +/- 1 mph up to 80 or so, and it is pretty amazing how much lower it reads in everyday riding - I have to remind myself that the speedo is giving me true speed and that I don't have the usual buffer.

I recall top-ending a new 750 back in the 70's and it would do about 112 mph indicated. The magazines and Honda said it would do 120 mph stock, but that would be more the exception than the rule. I not going anywhere near that with my 37-yo bike now. I've got an FJR which can get there in 10 seconds or so if the mood strikes me and do it safely (traffic, roads, wildlife, etc. permitting).

- Mark

dustyc · « **Reply #11 on:** May 22, 2008, 08:58:27 PM »

My 500's is dead on according to the radar thing. I haven't found one on the 750, but on a group ride with some modern bikes, we hit the ton and I had confirmation from others of our speed, so the 750's is at least in the ballpark and I don't have any reason to doubt it.

Gamma · « **Reply #12 on:** May 22, 2008, 11:55:07 PM »

Mine,s a Clarinet

troppo · « **Reply #13 on:** May 23, 2008, 12:05:41 AM »

If a trombone helps that much, has anyone tried a tuba?

oldbiker · « **Reply #14 on:** May 23, 2008, 01:29:33 AM »

Guess my Soprano cornet doesn't help much.

Shenanigans · « **Reply #15 on:** May 23, 2008, 01:43:05 AM »

I always assumed that my speedo was a little optimistic. So I just made up for it by going 108 indicated instead of 100

. Later after checking with a few of those speed trailers and the new speed signs they put up around here, turns out it was spot on. If only I had a tuba!

andy750 · « **Reply #16 on:** May 23, 2008, 04:33:49 AM »

Curious to know what the tach reading is in top gear @ 100mph?

I was cruising along at 7000rpm Sunday, 2-up on my CB750K4 and was wondering what speed I was doing - speedo is waaaay off on mine.

neil10 · « **Reply #17 on:** May 23, 2008, 04:55:22 AM »

115-125 depending on weight of rider

sparty · « **Reply #18 on:** May 23, 2008, 05:14:25 AM »

Quote from: andy750 on May 23, 2008, 04:33:49 AM

Curious to know what the tach reading is in top gear @ 100mph?

I was cruising along at 7000rpm Sunday, 2-up on my CB750K4 and was wondering what speed I was doing - speedo is waaaay off on mine.

Fast enough to get a nice ticket.

Sparty

andy750 · « **Reply #19 on:** May 23, 2008, 05:29:29 AM »

Quote from: sparty on May 23, 2008, 05:14:25 AM

Quote from: andy750 on May 23, 2008, 04:33:49 AM
Curious to know what the tach reading is in top gear @ 100mph?

I was cruising along at 7000rpm Sunday, 2-up on my CB750K4 and was wondering what speed I was doing - speedo is waaaay off on mine.

Fast enough to get a nice ticket.

Sparty

as always Art, you are so right

sparty · « **Reply #20 on:** May 23, 2008, 05:41:07 AM »

Quote from: andy750 on May 23, 2008, 05:29:29 AM

Quote from: sparty on May 23, 2008, 05:14:25 AM
Quote from: andy750 on May 23, 2008, 04:33:49 AM
Curious to know what the tach reading is in top gear @ 100mph?

I was cruising along at 7000rpm Sunday, 2-up on my CB750K4 and was wondering what speed I was doing - speedo is waaaay off on mine.

Fast enough to get a nice ticket.

Sparty

as always Art, you are so right

Finally It has stopped raining here. I will be on the bike this weekend. I'll be sure to see what speed 7000 RPMs in top gear looks like. With my gearing 17-48 it will be lower than 18-48.

andy750 · « **Reply #21 on:** May 23, 2008, 05:44:01 AM »

Im running 17/48 so we can compare....well at least to an extent...I dont have a Hot Rod engine

Have fun this weekend! Sunday is my day to get out....taking the cafe bike out for a run at some point as well.

cheers
Andy

bozo4onion · « **Reply #22 on:** May 23, 2008, 06:35:08 AM »

I think even a well tuned 550 will do 100+. I don't think I'll try it with all the stories of ancient frame geometry and the evil and hurty tank slap. As long we're tooting our own "horns", my 550 will never do >60 w/my drum kit.

sparty · « **Reply #23 on:** May 23, 2008, 06:45:53 AM »

Quote from: andy750 on May 23, 2008, 05:44:01 AM

Im running 17/48 so we can compare....well at least to an extent...I dont have a Hot Rod engine Have fun this weekend! Sunday is my day to get out....taking the cafe bike out for a run at some point as well.

cheers
Andy

Perfect for a comparo. I should find out in about 5 1/2 more hours! 4PM EST.

Sparty

Hope · « **Reply #24 on:** May 23, 2008, 07:33:41 AM »

You have a larger margin of error on your speedometer if you've changed tire sizes. This goes for cars and trucks, probably bikes too.

I have Buckshot Mudders on my 4x4 truck. These tires were not standard with my truck. It can throw my speedometer off 15 to 20mph, which is a pretty large margin for error. I usually just try to keep my truck well below the speed limit because I never really know how fast I'm going... unless I plug in my GPS. TomTom tells me how fast I am actually going.

So, the accuracy of your speedometer may depend on your tire size. Strap a TomTom to your bike and get an accurate read of your speed to tell how fast you are really going.

News:

Author Topic: Almost Ton Up? (Read 5649 times)

troppo