How much does your bike vibrate?

Posted: Sat Mar 28, 2009 3:00 pm

My 750 has more engine vibration than I would like. The last bike I had was a 81 KZ750 which I sold 23 years ago when my 1st kid arrived, so can't recall how smooth that one was. Curious about your experience and if there is anything that will lessen the vibration. Carbs have been rebuilt (and synched), new manifold boots, spark plugs, air cleaner, new tires, Dynatek coils and plug wires. Can't think of anything else I've done at this moment.

Posted: Sat Mar 28, 2009 3:53 pm

Vibration is kind of relative, especially without anything to compare it with. My experience with Honda's air-cooled DOHC 4's (750, 900 and 1100) is that they're pretty smooth. My CB1100F is smoother than my ZRX 1200. But the first CB1100F I had bought new had a slight buzz at around 4000 rpm that my current one doesn't. Make sure you don't have a vacuum leak, and check your engine mounts. I'm sure some of the very knowledgeable folks here will chime in with other suggestions.

Posted: Sat Mar 28, 2009 4:49 pm

I'm not positve but I believe the 750 is hard mounted to the frame.

Posted: Sat Mar 28, 2009 11:06 pm

My 900f vibrated quite badly around 5,000rpm till I put the kerker pipe on replacing what I think is a mac, this has happened on 2 different 900s anyone else have this occur ?

Posted: Sat Mar 28, 2009 11:22 pm

Historically speaking, the CB750 was the first four cylinder bike made, and the smoothest running bike at the time. The was even a Discovery channel show, the greatest bikes of all time, and the CB750 ranked number 3. They did a demo - they sat a glass of water on the seat and started the bike up. It ran so smooth the water hardly even rippled.

Here's the vid - Although I scoff at the label "dull ride"...

Link

Posted: Sat Mar 28, 2009 11:26 pm

Ya it was dull for the time because it handled WAY better that anything else ever made..
You didn't have to "work" at riding it, like say a Triumph.. Laughing

Posted: Sat Mar 28, 2009 11:31 pm

Back to the vibration, it really shouldn't vibrate. My bike is beat to hell and back (quite litterally) and it runs smooth. Maybe you have a tire out of balance? wheel bent? Chain link stuck? something else in the drive line?

You could always have a loose/worn engine mount (I have yet to dig into that, but I know for a fact cars with loose/worn engine mounts vibrate like a bear.)

Like I said, my bike has 40,000 miles on it, valves have probably never been adjusted, carbs are out of sync, idle is not set properly, and it still runs smooth once its opened up.

Posted: Sun Mar 29, 2009 2:16 am

The 750's definitely vibrate more than the 900's and 1100's with their rubber mounted engines. But to see if your bike is excessive for a 750 you need something to compare to, like another 750f. Comparing it to a kawasaki is hard to do.

I would agree in checking the items spartan8ball mentioned though.

Posted: Sun Mar 29, 2009 2:22 am

My 900F has always impressed me as being extremely smooth. You first need to identify if it is indeed an engine vibration or a chassis vibration. I have read that badly out of synch carbs can cause noticable vibration. It could very well be tire/rim related, however.

Posted: Sun Mar 29, 2009 4:15 am

Make sure all the engine mounting bolts are tight.

Posted: Sun Mar 29, 2009 4:43 am

MikeL wrote:

Vibration is kind of relative, especially without anything to compare it with. My experience with Honda's air-cooled DOHC 4's (750, 900 and 1100) is that they're pretty smooth. My CB1100F is smoother than my ZRX 1200.

That's funny, I just made this comparison somewhere else. There are multiple generations and all kinds of competing technology separating these bikes and my 900f is still a smoother running engine than the zrx1200, which gets a little buzzy in it's power range. There's no escaping the familiar engine rustle of a large inline 4 though.

Posted: Sun Mar 29, 2009 7:58 pm

If I remember correctly, the stock 900F bars had anti-vibration weights in the ends. Or maybe it's the sport kit bars, but one of them did. Anyway, if your bike has aftermarket bars, that may be the culprit. I've had very good luck using the BMW R-90S bars on mine, but they may not be good on your bike.

Posted: Sun Mar 29, 2009 11:17 pm

Is it a engine "buzz" or is it a bike vibe? where do u feel it, in the bars? or in the pegs? or all over? Yes the bars will buzz a bit depending on the rpm, quite normal.

does it do it in neutral at revs? then it engine, clutch in and coast at speed? and still vib? then its somethin else..Narrow it down for us.. Smile

comparing to other bikes is hard as a lot of newer I-4's had the engines as stressed members of the frame, they usually do buzz a fair bit at certain rpm,s, like the connie and others.. Some are rubber mounted, some have rubber mounted bars, etc, etc. Any luck you can find another 750 and compare..but yep, mine buzz's the bars at 60 mph enough to notice.. A bar end weight, bar's full of lead shot, softer grips, etc, etc, can help..

good luck!!

Posted: Mon Mar 30, 2009 2:11 am

Nitro, it's engine buzz. I see the mirror vibrate at idle and a bit more with a bit of reving. I retorqued all the engine mounting bolts today and I will have to see if that helps.

Posted: Mon Mar 30, 2009 2:27 am

Nitro wrote:

Is it a engine "buzz" or is it a bike vibe? where do u feel it, in the bars? or in the pegs? or all over? Yes the bars will buzz a bit depending on the rpm, quite normal.

does it do it in neutral at revs? then it engine, clutch in and coast at speed? and still vib? then its somethin else..Narrow it down for us.. Smile

comparing to other bikes is hard as a lot of newer I-4's had the engines as stressed members of the frame, they usually do buzz a fair bit at certain rpm,s, like the connie and others.. Some are rubber mounted, some have rubber mounted bars, etc, etc. Any luck you can find another 750 and compare..but yep, mine buzz's the bars at 60 mph enough to notice.. A bar end weight, bar's full of lead shot, softer grips, etc, etc, can help..

good luck!!

That's a good question. My 750 has a buzz at about 4200rpm that smooths out with higher RPM. Not enough to make your hands numb or anything but noticable.

Posted: Tue Mar 31, 2009 4:14 pm

My 1100 is very smooth--mirrors are sharp and clear and the bars don't buzz. There is some tingling in the pegs as I run through the gears at about 3500 rpm, but it goes away quickly. Sitting at idle there is some vibration visible in the mirrors and you can feel it in the bars, but it is very low amplitude.

Posted: Tue Mar 31, 2009 5:06 pm

All engines do this,some to a lesser degree,some more. if you dont like the mirrors bluring,and the feel in the handlebars,you can get some handle bar weights,in the org 1979 750fs they came stock in the bars.the longer one goes in the left and the shorter goes right.

Posted: Tue Mar 31, 2009 11:22 pm

seventyss wrote:

My 750 has more engine vibration than I would like. The last bike I had was a 81 KZ750 which I sold 23 years ago when my 1st kid arrived, so can't recall how smooth that one was. Curious about your experience and if there is anything that will lessen the vibration. Carbs have been rebuilt (and synched), new manifold boots, spark plugs, air cleaner, new tires, Dynatek coils and plug wires. Can't think of anything else I've done at this moment.

My 900fz gets a vibrashion thru it when it hits the ton anything under that its quite good regards Rod.

Posted: Tue Mar 31, 2009 11:23 pm

seventyss wrote:

My 750 has more engine vibration than I would like. The last bike I had was a 81 KZ750 which I sold 23 years ago when my 1st kid arrived, so can't recall how smooth that one was. Curious about your experience and if there is anything that will lessen the vibration. Carbs have been rebuilt (and synched), new manifold boots, spark plugs, air cleaner, new tires, Dynatek coils and plug wires. Can't think of anything else I've done at this moment.

My 900fz gets a vibration threw it when it hits the ton anything under that its quite good regards Rod.

Posted: Wed Apr 01, 2009 5:06 am

honda900fz wrote:

My 900fz gets a vibrashion thru it when it hits the ton anything under that its quite good regards Rod.

You need to lay off the weed dude... A ton?? What does that mean is Australia? Laughing

Posted: Wed Apr 01, 2009 5:39 am

CB900SS i smoke weed about 2 times a year
the ton in Aussie means 100 mph or 160 km
CB900SS you want to lay off the booze.

Posted: Wed Apr 01, 2009 5:45 am

honda900fz wrote:

CB900SS you want to lay off the booze.

I only drink sunday mornings...
Sorry for giving you such a hard time dude, I just don't understand half of what your saying. I will stop now.
From your interests in your profile I assumed you smoked weed like I used to. Razz

Posted: Wed Apr 01, 2009 10:54 am

CB900SS wrote:

honda900fz wrote:

My 900fz gets a vibrashion thru it when it hits the ton anything under that its quite good regards Rod.

You need to lay off the weed dude... A ton?? What does that mean is Australia? Laughing

My guess was 2000 rpm

2000 Lbs = 1 ton

Posted: Wed Apr 01, 2009 2:21 pm

A short ton is 2000lb,a long ton is 2200lb,...kph? or just slang for 100mph? I think the latter.

Posted: Wed Apr 01, 2009 2:24 pm

BINGO! What do i win?

Posted: Wed Apr 01, 2009 2:29 pm

Read the thing backwards

Posted: Wed Apr 01, 2009 4:21 pm

oy vey,

A ton is 1000 Kilos.

Not sure why a metric ton makes an imperial speed though.

Funny listening to you guys, like a school yard, verry funny.

Grant.

Posted: Wed Apr 01, 2009 4:28 pm

elcman wrote:

oy vey,

A ton is 1000 Kilos.

Not sure why a metric ton makes an imperial speed though.

Funny listening to you guys, like a school yard, verry funny.

Grant.

Actually - that would be a tonne. A tonne is a metric measure (1000 kilos) and a ton is an imperial measure (2000 pounds). In NZ we also referred to 100MPH as the ton. Not sure why.

Posted: Wed Apr 01, 2009 5:15 pm

"The ton" usually means 100 MPH.

"How much does your bike vibrate?" It doesn't......

Posted: Wed Apr 01, 2009 5:53 pm

My 1100F is one of the smoothest Bike I've owned.