Design change GS 1150 to improve Vibrations?

[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??

[Orbatos]

I actually have the same problem with my 1150, but due to the previous owner I have reason to believe worn cams are a contributor, though not the whole problem a carb sync may be in order as well. As it is my Mirrors are only usable from ~80-100 or so...

[earlfor]

You may be shocked at the difference a precise carb synch can make. I had a guy bring his GS 750 to me because it vibrated so bad that riding it made his/my hands itch and become numb in five minutes. After synching the carbs, the vibration was 98% gone.

Earl

I actually have the same problem with my 1150, but due to the previous owner I have reason to believe worn cams are a contributor, though not the whole problem a carb sync may be in order as well. As it is my Mirrors are only usable from ~80-100 or so...

[Anonymous]

Earl, the "85" & "86" 's didn't have rubber mounts on the foot pegs, they had weights added to the bottoms of the actual peg, I don't think the "84" models had them. It's amazing the difference in the vibes from these bikes. Some seem to have no vibration, some moderate, and some, like both of mine, very bad. Both of mine have have pod air filters, I've never heard this before, but wondered if they may cause inaccurate vacum readings while syncing the carbs or the maybe the pods may cause some kind of imbalance at higher rpm's. Not likely, but I'm just looking for something. Does your 1150 with the stock air box vibrate, or is your 1150 with pod filters have little or no vibration? Will be interesting to know. Shouldn't matter, if the ones with the stock air boxes didn't vibrate, Suzuki wouldn't have used thoes rubber motor mounts & vibration dampeners.

[kz]

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.

Dyna 2000 is now mounted , no change in vibrations.

Of course, Dyna 2000 has other advantages.....

[kz]

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 Earl,

I did this so far:

1. Changed to Dyna 2000, no difference.

2. See 1.

3. I have run this bike with two different engines, the stock engine vibrated less then the replacement one.

I overhauled the stock engine, complete head work with bigger size valves, the valves are adjusted many times on both engines to my best knowledge and I can't see that it has any influence on the vibrations.

4. I have had two completely different electrical harnesses on this bike, different stators, and different regulators. No change in vibrations.

5. I have used two different set of stock carbs and are now using Mikuni RS 36 and can't get rid of the vibrations. However if the carbs are out of sync, the vibrations are worse.

6. I have used at lest three new chains on this bike, and I don't think my problem is related to the chain.

At last yes, at about 3.800 rpm and below.