Design change GS 1150 to improve Vibrations?

[cbxchris]

If I ever have to take my 1150 down I am positively going back with a 1100 crank. I have not tried new rubber engine mounts. That will be a good winter time project. I know on drag bikes most people eliminate those. You should feel a 1150 then. 8O

 

[Dink]

Chris replace the rubber bushes, it is a ten minute job. to finish the hour off re-torque your engine mounts and see if that helps.
Dink

 

[Anonymous]

Thanks guy's, this discussion has shed more light on the vibe problem than I'd ever heard before. I've done all I can do to my "86" model, but the mirrors may as well not be there, aboye 4500 rpm. It seems I must have one of the worst vibrating ones, my "85" model isn't nearly as bad, but much worse than the 1100's. Thanks for shareing your imfo. And I still beleive that Suzuki knew early about the problem, thus the vibration dampeners in the bars & footpegs & the rubber mounts.

 

[earlfor]

Karl, my 1150 is stock and all original parts. The only changes I have made from stock are different rear turn signals, a xenon headlight bulb, an
electronic digital tachometer, and two inches of foam removed from the seat to lower the sitting position. I replaced the stock leaded handlebar ends with hollow stainless steel tube which if anything, would make vibration worse, but that made no difference. I have replaced the R/R and stator, but it didnt vibrate with the stock stator either. I replaced the clutch linings too, but it never vibrated with the old linings either. The 1150 does not vibrate or shake at all at any rpm and there is no high frequency buzz at high rpm. If it wasnt for the tachometer, I wouldnt know the engine was running at highway speeds.

I have found the bike to be fussy relative to carb synch. If the synch is a little bit off, it makes a big difference. Also, the stock main jetting is Mikuni #120's on the 1 and 4 cylinder and #122.5's on the 2 and 3 cylinder. I could not get an equal plug burn with that jetting and once in a while, the 2 and 3 cylinders would skip/spit because of it. I am running 122.5's in all carbs now and the plug burn is better. The bike runs even smoother.

I have installed a Dyna 2000 ignition system. I have found the bike does not tolerate the slightest difference in ignition timing between the 1,4 sensor and the 2,3 sensor. It will run noticably rough if there is one degree difference.

The Dyna 2000 has programmable ignition timing curves. I have the full 32 degrees of advance programmed (delayed) until 4500 rpm is reached..
Thats about 1000 rpm later than the stock ignition advance curve.

The factory service manual specifies 89 octane fuel. The bike seems to run smoother on 89 than it does on lower octane.

In short, carb synch and ignition timing seem to make the biggest differences in smoothness.

The bike starts instantly when cold and idles at a smooth and steady 800 rpm when cold. Once at normal operating temperature, it idles at 1100 rpm. Normal oil temp is around 190 degrees.

Earl

Earl is your 1150 "pure" stock? Even the rear shock absorber?

/Karl

BTW:

Having second thoughts about rebuilding my engine if I have to live that @?@@@?? vibrations....

 

[lhanscom]

On the other end of the spectrom (not stock), I don't have much vibration, it buzzes a bit around that 4500 area, but nothing that bothers me much, hands don't go numb, and mirrors are fine. My crank was balanced by Falicon, and I have the 1229 kit in it. Ignition is the Dyna S. I noticed a big difference when I balanced the carbs, it seems these engines are very particular on the amount of power each cylender puts out. Just a thought, if ignition timing, and carb balance makes a significant difference in vibration, wouldn't compression also make a diffence? So if one cylender is lower then the rest, vibration would go up?

 

[mpogue]

Are you guys saying that at 60/70 mph your mirrors are clear? :? After all I've done, everything in my mirrors are still blurry. The bike rides great and has what I see as minor vibration. At 4000-4500rpm I do have some fairing buzzing, but thats it.

 

[earlfor]

At 60 mph or less, my mirrors are the same as if the bike is sitting still without the engine running. At about 65 mph, I can see traffic to the rear clearly (perfect focus) at any distance up to 1/4 mile or so. There is some vibration evident in viewing more distant images, but it is not a problem.
At 75 mph and above, the mirrors vibrate enough that I cannot tell the difference between a Ford and a Chevy at distance, but that is about all. At 100+, they are not much use. I dont feel the vibration at any speed.

I forgot about one modification. A while back, I wanted new mirrors and couldnt find any I liked with long stalks. I bought the style I liked and hacksawed the stalks in half. I then bought a 5" length of 3/8" inside diameter copper pipe for each mirror stalk. I drilled the inside of the copper pipe the same diameter as the outside of the mirror stalk so the mirror stalk would insert into the pipe at each end. This was to increase the length of the mirror stalks. I used J.B. Weld to glue the mirror stems into the pipe ends. I think the effect may have been about the same as
leading the handlebars. Mass is increased and vibration apparently is deadened. That wasnt my original intent though.

Earl

Are you guys saying that at 60/70 mph your mirrors are clear? :? After all I've done, everything in my mirrors are still blurry. The bike rides great and has what I see as minor vibration. At 4000-4500rpm I do have some fairing buzzing, but thats it.

 

[lhanscom]

At 80 I can look into my mirrors and they're moving a bit, but the focus is fine. I think the movement has more to do with wind and road surface then engine vibes. When over 100, I haven't taken notice of my mirrors shaking, but I'm usually concentrating more on what's in front of me at that point.

 

[mpogue]

I think I see why you're mirrors are clearer than mine Earl, you have them mounted on the handle bars. Mine is on the fairing.

As for Luke, if yours is a ES, your mirrors are on the fairing. You're probably right about some of it being road and wind. I'll have to pay more attention at low speed to see when the mirrors get blurry at what rpm. I remember from my last ride, I was lucky to guess what colour the vehicle is unless he's real close.

Thanks.

 

[lhanscom]

Currently I'm in ES mode, so the mirrors are on the fairing, I've also been in E mode, and had no problems with the mirrors.

 

[kz]

I have installed a Dyna 2000 ignition system. I have found the bike does not tolerate the slightest difference in ignition timing between the 1,4 sensor and the 2,3 sensor. It will run noticably rough if there is one degree difference.

The Dyna 2000 has programmable ignition timing curves. I have the full 32 degrees of advance programmed (delayed) until 4500 rpm is reached..
Thats about 1000 rpm later than the stock ignition advance curve.

Earl, I have not made any changes to the ignition and are running stock.

Did you notice any differens with the vibrations after you installed the Dyna 2000 or has the bike always been OK?

As you can see from the replys here, your GS seems to be unique... :roll:

/Karl

 

[earlfor]

Karl, now you have me thinking. As I said, everything as far as frame, rubber engine mounts, shocks, forks, etc is stock. I have replaced electrical components, but except for a few, I do not think they would have anything to do with vibration. The bike had the original factory non adjustable ignition system when I bought it. It did not have an objectionable vibration level when I bought it, but it did need a carb synch. It was acceptably smooth, but not as smooth as it is now.

The only things I have changed that I believe would have any effect on smoothness are the ignition system setup and the carb synch. Changing the main jets in the 1 and 4 cylinders to 122.5's smoothed out those two cylinders response. Those two cylinders were running a little too lean and I could not get the fuel flow correct without increasing the vacuum levels on 1 and 4, which resulted in the vacuum level on 1 and 4 being too great a difference to the 2 and 3 vacuum levels, and that made my vacuum levels too out of balance. (unfortunately, if your 1 and 4 cylinders are not running lean, I dont think this is part of your problem)

I am running the 1 and 4 cylinders with 1 in. (2.5cm) more vacuum than the 2,3 cylinders when the bike is running at 1800 rpm.

The bike runs smoother with the Dyna 2000 ignition. I also have high output Accel coils and graphite plug wires. I run 35 thou plug gaps on stock NGK D9ES plugs. I think part of why the bike runs so smooth is the ignition system. I think the main advantage the Dyna 2000 has is it is adjustable and it has a degreed plate. You dial in the total advance desired on the plate, then set the curves on the ignition module/box. It also lights and indicates when the curve is starting relative to the crankshaft degrees and indicates duration. There is no guesswork at all. It is precise. The stock ignition is not adjustable. In retrospect, I think my tuning problems in the first year I had the bike were largely due to a stock ignition system intermittently malfunctioning. I could never figure out why it seemed to run differently at times. It took about a year before the stock ignition finally died completely. Since replacing it with the Dyna 2000, the bike has run better than ever.

I spent about a month with three sets of new spark plugs in synching the carbs. I would synch the carbs, put in a new set of plugs and run the bike 50 miles. Once home, I pulled the plugs to read them, made vacuum and jetting adjustments, installed a new set of plugs and then ran the bike another 50 miles and came back to read the plugs again. As I used a set of plugs, I soaked them in vinegar overnight to clean them. I always make my 50 mile test ride with a fresh set of plugs so I could see the effect of the changes I had made. It took about 20 rides before I got all cylinders running exactly as I wanted.

I cannot believe everyone with an 1150 has vibration due to a twisted or out of balance crankshaft. I dont think that is possible. Hardened rubber isolators on the engine will make a big difference. Sloppy valve clearnaces will also contribute to vibration. (mine are recently adjusted) I believe, ignition voltage, advance curve setup and carburation explains why my 1150 is as smooth as it is. I dont think mine is any different than anyone else's bike.

Also, it appeared to me that the stock ignition module was feeding in 33 1/2 degrees of total advance. Excessive advance will increase midrange vibration levels. (that is my opinion from measurement and road test preceptions)

Retarding the timing a degree or two sometimes will decrease vibration levels. (another of my opinions by experience)

Mismatched voltages to the coils and/or different outputs between the two coils produces a vibration prone engine.

I think the vibration problems are a combination of a dozen little variations with each one by itself not being enough to be a concern.

I rode a new 1200S Bandit a few months ago and it was not one bit smoother than my 1150. If you have ridden the 1200S, then you know exactly what the vibration level on my 1150 is.


Earl

Earl, I have not made any changes to the ignition and are running stock.

Did you notice any differens with the vibrations after you installed the Dyna 2000 or has the bike always been OK?

As you can see from the replys here, your GS seems to be unique... :roll:

/Karl

 

[kz]

Hi again,

I have now replaced the engine, the buzzing/vibrating changed to the better for sure. However I'm not completely satisfied......

I am now certain of that the buzzing/vibrating in the handlebars is related to the engine.

The crank in this engine is now welded and checked, but not balanced in a balancing machine.

Maybe I try to balance the crank with a portable instrument this winter, just have to set up the crank properly for balancing...

 

[Anonymous]

Why not to use an Earlfor solution with Dyna 2000 and good coils ?
I think this is a road worth checking and as soon as cash will be there I will try it.

Adam M.

 

[earlfor]

Karl, I think its possible your crank could be a tiny bit out of balance, but I dont think it is likely that Suzuki would have mass produced out of balance cranks. The 1150 was their top of the line machine and a problem such as that would have been addressed.

I think it is probably a combination of little things that are not quite right and together, they cause a bigger problem. Some of the things that could contribute are:

1. An intermittently malfunctioning ignitor box, and possibly the advance function not correctly operating.

2. Factory ignition timing not correct (mine was not and this was on a non adjustable ignition)

3. Valve adjustments out of spec. It occurs to me that if the valves are out of adjustment beyond a point, then the intake duration and fuel charge will not be balanced between the cylinders. Power pulses would then be different strengths.

4. Unbalanced voltage supply/output between the coils. That would give different combustion and power levels between the cylinders.

5. Carb vacuum synchronization ................ On my 1150, a precise synch makes a huge difference in vibration level. I use a Morgan Carbtune.

6. You are going to laugh at me for this one, but a dry, binding link in the drive chain when at speed can feel like an engine vibration.

Is there any rpm when you are riding down the road, that the mirrors become smooth and show decreased vibration levels?

Earl

Hi again,

I have now replaced the engine, the buzzing/vibrating changed to the better for sure. However I'm not completely satisfied......

I am now certain of that the buzzing/vibrating in the handlebars is related to the engine.

The crank in this engine is now welded and checked, but not balanced in a balancing machine.

Maybe I try to balance the crank with a portable instrument this winter, just have to set up the crank properly for balancing...

 

[Anonymous]

I keep waiting for someone to come up with the answer. I still think Suzuki knew there was a vibration problem with the 1150's, thus the rubber motor mounts & vibration dampeners in the bars. They for sure knew of the problem after "84", the first year, but instead of fixing the problem, they tried to hide it with different size handlebar weights & now vibration dampening weights on the foot pegs. Just wondering, did Suzuki ever use rubber motor mounts or vibration dampeners on any other GS models?

 

[Carter Turk]

I've have a Falicon super crank in my 1150 with rubber motor mounts welded to stock Katana mounts as the engine is in an 83 Kat frame. The thing vibrates. It vibrated horribly without the rubber motor mounts.

With them, it still vibrates, but actually since I got talked into a big bore kit with Gisxr carbs it buzzes less. It might be the vibs are more baratone now, less high buzz.

I rode a friends ZRX, what a smooth motor. It just spools up, no drama, and there in lies the problem.

 

[earlfor]

I have an 85 E and the footpegs are solid mounted, no rubber dampening.
I've replaced the stock leaded handlebars with hollow stainless steel tube with no dampening weights at all........nothing but the tube and grips.
To look at the images in my mirrors, you would swear the bike was electric. Has anyone loosened the engine mount bolts and replaced the isolation rubbers with new, pliable ones, then retorqed the engine mount bolts. They can make a big difference if dried out or not evenly tightened.
I havent seen any rubber isolation mounts on any other GS, but then, I havent worked on every year/model Suzuki made.

Earl

I keep waiting for someone to come up with the answer. I still think Suzuki knew there was a vibration problem with the 1150's, thus the rubber motor mounts & vibration dampeners in the bars. They for sure knew of the problem after "84", the first year, but instead of fixing the problem, they tried to hide it with different size handlebar weights & now vibration dampening weights on the foot pegs. Just wondering, did Suzuki ever use rubber motor mounts or vibration dampeners on any other GS models?

 

[earlfor]

Is the vibration level enough to numb your fingers and if yes, how long does it take to do so? I have spent 12 hour days on the 1150 and my butt gets tired, but hands and feet are fine. Also, at what speed does the vibration start to be objectionable. I get zero vibration up to about 70-75 mph. Above 75, I still cant feel any, but I can see my mirrors start to show some vibration because the image begins to go out of focus. My mirrors are still useful up to about 100 or so. Above that, I dont worry too much about traffic overtaking anyway.

Earl

I've have a Falicon super crank in my 1150 with rubber motor mounts welded to stock Katana mounts as the engine is in an 83 Kat frame. The thing vibrates. It vibrated horribly without the rubber motor mounts.

With them, it still vibrates, but actually since I got talked into a big bore kit with Gisxr carbs it buzzes less. It might be the vibs are more baratone now, less high buzz.

I rode a friends ZRX, what a smooth motor. It just spools up, no drama, and there in lies the problem.

 

[SqDancerLynn1]

If the vibration is really bad the crank may be twisted Have you synced the carbs??