GS 1150 - Prone to vibration?

[49er]

Hi All
I am looking at buying an 1150. I hear that they are prone to vibration. Certainly many I have seen photos of have weights fitted to the handle bars. Is the vibration caused though engine harmonics or a slight imbalance of the reciprocating mass?

[aosmith]

as silly as this sounds i've heard of people having vibration issues from rubber guards between the fins on the motor... Otherwise i haven't seen anything about vibration and i'm a troll around here

[SqDancerLynn1]

A good carb sync can make a big difference on any bike

[rphillips]

I think I remember I've seen where two people here have 1150's that don't vibrate. Hopefully this will bring out more. I have 1 now, & just sold my other. Both of them vibrate. The one I sold, you could ride nearly 70 mph before the mirrors buzzed so you couldn't see behind you, the one I still have, about 60 or 65 & the mirrors are buzzed out. I've tried everything, short of balancing the crankshaft, but nothing seemed to help. I replaced the motormounts, re-torqued mounts to spec, I synced carbs myself, then payed pro to do it & get them as perfect as he could again, adjusted valves, replaced clutch basket, filled bars with shot to try to lessen vibes in hands. Nothing changed. I've owned & ridden several GS 1100's & 1000's & 750's, but none of them vibrated nearly as bad as these 2 GS 1150's, & none of them had the external vibration dampeners that the 1150's have. These are the only 2 1150's I've ever ridden, and by this, in my opinion, the GS 1100's are by far my favorite. Not only the vibes, but the seat has a limited seating position, the others let you move around a little, suits me better for long rides.

[renobruce]

I had a consistent vibration on mine at about 4,000 rpm... I could never get it to stop.....until I bought a Morgan Carbtune. It now runs like a sewing machine. The 1150's are super-sensitive to carbs out of synch. I could never get the synch good enough with mercury sticks.

[earlfor]

Thats dead on! Mine was the most sensitive to a carb synch of any bike I have worked on. Morgan Carbtune only on that bike. Forget mercury sticks.

Earl

I had a consistent vibration on mine at about 4,000 rpm... I could never get it to stop.....until I bought a Morgan Carbtune. It now runs like a sewing machine. The 1150's are super-sensitive to carbs out of synch. I could never get the synch good enough with mercury sticks.

[49er]

Thats dead on! Mine was the most sensitive to a carb synch of any bike I have worked on. Morgan Carbtune only on that bike. Forget mercury sticks.

Earl

Thanks for the feedback guys. I have a Morgan Carbtune so I guess there shouldn't be too many bad vibes.
Cheers

[GS Farmer]

Morgan carbtune

Where do you buy the morgan carb tune and how much?? My bikes due for a valve adjustment and carb sync.

[KSP]

Thats dead on! Mine was the most sensitive to a carb synch of any bike I have worked on. Morgan Carbtune only on that bike. Forget mercury sticks.

Earl

Is that the Carbtune II you are referring too?

[49er]

Where do you buy the morgan carb tune and how much?? My bikes due for a valve adjustment and carb sync.

Here's a link to their site. http://www.carbtune.com/carbdtls.html
In my opinion, the best carb sync tool currently available. You will need to contact them for a price.

[49er]

Is that the Carbtune II you are referring too?

Yes, Carbtune II.

[49er]

Taking a punt - GS1150

Thanks for the feedback guys. I have a Morgan Carbtune so I guess there shouldn't be too many bad vibes.
Cheers

Well, I've bitten the bullet and bought one.

The PO has lovingly restored this one to its former glory. It's an '83, blue/white with 24K miles and is stock except for a V&H 4-1. Apart from a couple of minor blemishes, it's in showroom condition.
I was apprehensive about the renowned vibration associated with most of this model at around 65 -70mph in top. The PO assured me that this one didn't and he was right. I haven't found any appreciable vibration at any rpm.
I have a theory concerning the vibration that many 1150's have, but it is only that.
Since most past and present owners agree that an accurate carb sync is essential, I was wondering if this vibration was more pronounced on bikes that are still running the stock designed 4-2 exhausts. If so, the balance tube between #2&3 pipes may be agrivating harmonics instead of balancing them. The more out of sync the carbs are, the greater the vibration produced through the frame and its attachments!
The top end was freshened in 2004 after the bike had sat for some years. #3 sleeve was replaced and they all were honed to accept the new rings. No other new components were fitted apart from the necessary gaskets and seals.
The bike just loves long rides.
The PO included a Suzuki Service Manual and a copy of '84 Motor Cyclist with the first road /track test of this model in the US. The article mentions two traits that the test riders found annoying. The first was the now customary vibration at 60-65mph, the other was that the bike had a tendancy to stand up when late heavy braking was attempted into a corner. I have found this to be correct, in the short time I have owned mine. It's something new owners need to be accutely aware of.
The power and handling are very good, even through tight sections, but don't ever misread the tightness of a corner!
I'll put some pics on photbucket.
Cheers

[Dink]

The first was the now customary vibration at 60-65mph, the other was that the bike had a tendancy to stand up when late heavy braking was attempted into a corner. I have found this to be correct, in the short time I have owned mine. It's something new owners need to be accutely aware of.
The power and handling are very good, even through tight sections, but don't ever misread the tightness of a corner!
I'll put some pics on photbucket.
Cheers

When originally manufactured, GS1150 motors were placed into the frame upside down(seriously!!) this resulted in the motors being in tension, the very first trick to deal with the "vibes" was to release all the engine mounts and re-torque them.
Secondly if you arrive at a corner too fast on an 1150, use the rear brake only as this counters the "stand up" tendency created by the differences in mass of the 16" front wheel to the rest of the bike, if you are going way too fast use the front as well, but still with a strong rearward bias, and push hardf on the inner bar, an 1150 is a way more responsive handler than it has any right to be.

Dink

[49er]

When originally manufactured, GS1150 motors were placed into the frame upside down(seriously!!) this resulted in the motors being in tension, the very first trick to deal with the "vibes" was to release all the engine mounts and re-torque them.
Secondly if you arrive at a corner too fast on an 1150, use the rear brake only as this counters the "stand up" tendency created by the differences in mass of the 16" front wheel to the rest of the bike, if you are going way too fast use the front as well, but still with a strong rearward bias, and push hardf on the inner bar, an 1150 is a way more responsive handler than it has any right to be.

Dink

Thanks for the feedback Dink.
I do use plenty of rear brake during normal braking. When I first bought this bike, the rear end wasn't set up right for me. It was too hard and skittery. I have softened the preload and rebound by one setting. The tire pressure was in the ball park. The back end now has far greater feel and is much more predictable.
I am happy with the general performance and handling, with the exception of this "stand up" trait. It is a real safety concern. I guess that's one of the reasons that Suzuki only made the model for 2 years.
The difference in emergency braking characteristics into a corner, between the 850 and the 1150 are quite pronounced. In comparison, the 850 is very well mannered.
Why did Suzuki mount the 1150 motors in the frame upside down? Sounds absurd to me. Mounting them back to front would make more sense. They could then have driven the front wheel and made a real feature of this "stand up tendancy"!! :-D

[Dink]

The stand up tendancy is simple gyroscopics, a 16" has a far lower effect than a 19" front wheel, it also creates that steered by thought feel that the 1150's have. when I first got mine the largest bike I had previously owned was a 400, so there was a steep leaning curve; i.e. Idid not use rear brakes at all before I got The Tractor, as I adapted to it I found the rear brake was overly touchy for my liking,so I fixed it by puttinf EBC pads in, this deadened the rear brake off nicely.
By the time I got my Katana; which has been modded to 18" wheels front & rear, I was so used to the 16" front on The Tractor, I couldnt believe what a pig of steerer the Kat was. Nearly got me into serious trouble a couple times.

Dink