Maxes-out around 55mph. 81 CB750 DOHC

barnett468 said:
we need to know what your gears are.

it sounds like it is geared low so it doesn't have a lot of top end which should make it really fast when accelerating.
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K I'll get some gear info for ya, why would gear it to be slower on the high end? For track racing? I'd be very happy with some new gearing if that's the case. The first gear is great, everything up is lame. I'm usually skipping the second gear as its kinda pointless.

This post has gone on a roller coaster... And now here's another twist... This morning I just picked up the bike from the impound. I knew it would happen eventually but not like this... The bars are twisted, grips aren't gripping, and the engine is scratched up and head gaskets torn up. When I got back to where it was towed from a guy showed me some pics. That's not how you tow a bike! WTF!
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Hooks are on a rotation in the city mang... they don't have to meet any "motorcycle" spec to get a permit and they don't GIS either way... Find a garage close to where you work and pay the lot dude a monthly chunk to find you a hole behind a dumpster or something... Has to be a spot you can go to every time somewhere. Dig.

As for the damage, if you have insurance they cover this stuff under the "comp" side, but you pay the deductible.
 
Joseph New York said:
K I'll get some gear info for ya, why would gear it to be slower on the high end? For track racing? I'd be very happy with some new gearing if that's the case. The first gear is great, everything up is lame. I'm usually skipping the second gear as its kinda pointless.

This post has gone on a roller coaster... And now here's another twist... This morning I just picked up the bike from the impound. I knew it would happen eventually but not like this... The bars are twisted, grips aren't gripping, and the engine is scratched up and head gaskets torn up. When I got back to where it was towed from a guy showed me some pics. That's not how you tow a bike! WTF!
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1. why is your bike on a tow truck in the first place?

2. i have no idea why someone changed your gearing if they did . . thats like asking why some guys like fat chicks....who the hell knows....but until you tell us what your front and rear gears are, or whether you like fat chicks or not, i doubt there's much else anyone can suggest.
 
Funny the blond Russian girl on the bike is wearing skinny jeans in July... those "models" tend to be as naked as possible this time of year ::)
 
Tune-A-Fish said:
Hooks are on a rotation in the city mang... they don't have to meet any "motorcycle" spec to get a permit and they don't GIS either way... Find a garage close to where you work and pay the lot dude a monthly chunk to find you a hole behind a dumpster or something... Has to be a spot you can go to every time somewhere. Dig.

As for the damage, if you have insurance they cover this stuff under the "comp" side, but you pay the deductible.
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Twas the NYPD that towed me. Looked into it, they can tow like that. Still going to raise hell though, aint right bending up people's handlebars.

I have a garage, but $300/mo per bike x 3 isn't ideal, so this summer two of em are gutter punks. They take turns.

It's a treat; "models" with yoga pants year round. No complaints there
 
barnett468 said:
1. why is your bike on a tow truck in the first place?

2. i have no idea why someone changed your gearing if they did . . that's like asking why some guys like fat chicks....who the hell knows....but until you tell us what your front and rear gears are, or whether you like fat chicks or not, i doubt there's much else anyone can suggest.
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1. Didn't have my license plate on. Gotten away with it for years, but Mayor buzz kill decided to display his biker-envy.

2. Gett'n back to ya about the gears. I guess people change the gears because they like going slow. Same for liking fat chicks.

Would I change the front or rear sprocket size to increase highway speed?
 
You can change either.

More teeth on the front for more top end and less teeth for more acceleration.

Opposite on the rear.

Generally changing the rear is better.
 
Joseph New York said:
1. Didn't have my license plate on. Gotten away with it for years, but Mayor buzz kill decided to display his biker-envy.

2. Gett'n back to ya about the gears. I guess people change the gears because they like going slow. Same for liking fat chicks.

Would I change the front or rear sprocket size to increase highway speed?
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i would not change anything until you find out exactly what the problem is . . it sounds like one of the problems may be that you don't rev it past 4500 rpm . . you need to hold the throttle wide open in 3rd gear for 5 seconds then come back and tell us how far it revved to . . if it only revs to 5 k, then you have major probs.

if your gear ratio is numerically higher than stock by just 10%, that thing should lift the front wheel over your head as it throws you on the ground when you open the throttle all the way.

theres not much we can do until we also know EXACTLY how far it will rev.

.
 
Tune-A-Fish said:
Funny the blond Russian girl on the bike is wearing skinny jeans in July... those "models" tend to be as naked as possible this time of year ::)
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....................................Are you referring to this one?

...........................
images
 
barnett468 said:
i would not change anything until you find out exactly what the problem is . . it sounds like one of the problems may be that you don't rev it past 4500 rpm . . you need to hold the throttle wide open in 3rd gear for 5 seconds then come back and tell us how far it revved to . . if it only revs to 5 k, then you have major probs.

if your gear ratio is numerically higher than stock by just 10%, that thing should lift the front wheel over your head as it throws you on the ground when you open the throttle all the way.

theres not much we can do until we also know EXACTLY how far it will rev.

.
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Yeah, it would without a doubt far surpass 5k in 5 secs in any gear. I know I could get it to redline at 10k in like 3 secs, but wouldn't dare... Anything above 4500 the bike vibrates so bad my nerves stop me from pushing harder.

I agree that I could be the issue, that I'm not revving enough. Before putting a tach on, the vibrations and screaming exhaust (shorty 4-1 de-baffled) made me think I was at twice the RPMs I was actually at.

Perhaps my next move should be fixing the vibration.


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Joseph New York said:
I know I could get it to redline at 10k in like 3 secs, but wouldn't dare. Anything above 4500 the bike vibrates so bad my nerves stop me from pushing harder. I agree that I could be the issue, that I'm not revving enough. Before putting a tach on, the vibrations and screaming exhaust (shorty 4-1 de-baffled) made me think I was at twice the RPMs I was actually at.
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Joseph New York said:
Perhaps my next move should be fixing the vibration.
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Perhaps...


OMG...I think I just wet myself!

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barnett468 said:
Perhaps...


OMG...I think I just wet myself!

graphics-laughing-867787.gif
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Yeah yeah, laugh all ya want barnett :)

I'm going to re-sync the carbs this weekend, hopefully that will cure some of the vibration, but I'm doubting it as I just went through em. It does feel like the vibration comes from the engine and not wheels/fork.

If it's not my carbs out-of-sync, what else could cause this numbing vibration at 4.5+ RPMs? I checked my engine mounts, not sure what could be causing it.


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Joseph New York said:
Yeah yeah, laugh all ya want barnett :)

I'm going to re-sync the carbs this weekend, hopefully that will cure some of the vibration, but I'm doubting it as I just went through em. It does feel like the vibration comes from the engine and not wheels/fork.

If it's not my carbs out-of-sync, what else could cause this numbing vibration at 4.5+ RPMs? I checked my engine mounts, not sure what could be causing it.
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without holding the bars, just sit on the bike and rev it to 2000 for 5 seconds then 3000 for 5 seconds then 4000 for 5 seconds and tell us what happens . . if it vibrates more with rpm, it is the engine.

running on 3 cyls will cause a vibration
.
.
 
barnett468 said:
without holding the bars, just sit on the bike and rev it to 2000 for 5 seconds then 3000 for 5 seconds then 4000 for 5 seconds and tell us what happens . . if it vibrates more with rpm, it is the engine.

running on 3 cyls will cause a vibration
.
.
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Yeah, good idea. Will do it.

When it was running on 3 it shook pretty bad, had trouble idling, loss power. I could tell immediately a cylinder stopped firing, it's not acting like that. I regularly feel the headers, but it's a good point.

Test it tomorrow, thx


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Joseph New York said:
Yeah, good idea. Will do it.

When it was running on 3 it shook pretty bad, had trouble idling, loss power. I could tell immediately a cylinder stopped firing, it's not acting like that. I regularly feel the headers, but it's a good point.

Test it tomorrow, thx
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ok, cool let us know.

if the wheels are not balanced it can vibrate.

if the wheels are not tru, it can vibrate.

put the bike on the center stand and spin the front wheel and look at it from the front to see if it wobbles.

if your rear wheel is off the ground, start the bike and put it in first gear and look at the rear wheel to see if its not true.

if the tires have flat spots pr scallops on them. it will vibrate.

.
 
Joseph New York said:
1. Didn't have my license plate on. Gotten away with it for years, but Mayor buzz kill decided to display his biker-envy.
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When I lived in Queens, I pop riveted my plate on. Kept me legal and the plate could not be stolen easily.
 
Mydlyfkryzis said:
When I lived in Queens, I pop riveted my plate on. Kept me legal and the plate could not be stolen easily.
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My plan too! I've used Velcro for years on all my bikes in Manhattan, but it fails after a while and I've been thinking about rivets. Thanks for verifying it.

This year my rules have changed, I'll never take off my plate off above 14th st, but downtown is still cool IMO.

I've never had a plate stolen, but the rivet idea will surly help continue that. Although I just jinxed myself


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barnett468 said:
without holding the bars, just sit on the bike and rev it to 2000 for 5 seconds then 3000 for 5 seconds then 4000 for 5 seconds and tell us what happens . . if it vibrates more with rpm, it is the engine.

running on 3 cyls will cause a vibration
.
.
Click to expand...

It's the engine. Tested in park, and going 55 I idled the engine.

I get buzzing from it, and most the vibration comes from the tank. Bars too though.

Checked engine mounts, didn't get a sync in this weekend, will this week though.


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