Design change GS 1150 to improve Vibrations?

[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.

 

[kz]

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?

I'm would also be interested in that answer..........

I'm convinced that the problem is related either to the engine or/and the mounting of the engine.

The frames design is also suspected by me.....


BTW:

What can give us hope, is that Earls bike doesn't vibrate.

 

[kz]

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

Agree, I think that is the reason why the vibritions now are less with the overhauled engine with an overhauled welded crank.

Carbs are synced, as I wrote before, if carbs are out of sync, vibrations get worse.

 

[kz]

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.

I'm going for 1327 now, see what happens next week if the weather allows any testing.

BTW:

The 1197 didn't came out well , so it's just to start again (the 1197 problem is not related to the vibrations more a question of knocking engine.)

 

[kz]

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.

That speaks for tolerance differences somewhere.

I just can't get the unbalance theory go, the reason why it probably not has been tested so many times is probably because it' difficult to mount the crank in an ordinary balancing machine.

Anybody here ever balanced a GS1150 crank and used it in a stock engine?

 

[earlfor]

I dont have any experience with pod filters on an 1100 or 1150. I do have experience with 1000's with pods and with stock airbox/filter. The 1000 runs very noticably smoother with the stock airbox. I dont know exactly why though. The only reason I would replace a stock airbox with pod filters is if the stock airbox was an oh my god to install and remove.
(it is on the 1000's) Pods give a small hp gain in upper rpm, are about the same in mid range and terrible at low end compared to the stock airbox.
(my opinion) Gas milage has decreased on all bikes with pods compared to stock in my experience. I think there is a high probability that pod filters would contribute to causing a rough running/vibrating 1150.

My 1150 is stock airbox and filter. The only change I have made to my carbs is a main jet change. Stock is Mikuni jet #120 in 1 and 4 carb and #122.5 in the 2 and 3 carb. I run 122.5 mains in all four carbs.

Earl

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.

 

[earlfor]

I noticed a difference with the Dyna 2000. The bike runs better with it than it did with the stock ignition. I assumed the vibration level was lower because the Dyna is more accurate. The bike was reasonably smooth when I bought it. It had some vibration, but it was not objectionable and was never enough to numb my hands. I wish you were close enough to be able to take it for a test ride. The vibration level is lower than a new 1200 Bandit. Twist the throttle and you would think you were on a turbine.

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

 

[earlfor]

Yes it does. It makes setup so easy and precise, it is a joy.
There is no comparison between it and the stock or "S" system.

Earl

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

 

[kz]

Hi again,

Have now switched to the 1327 engine, I wouldn't go as far as Earl and compare the the engine with a turbine, but for sure the vibrations/buzzing is better than ever before.

 

[Anonymous]

Would you be kind enough topass some information about your new engine ?
according to comon knowledge bigger engine should be vibrating more, not less.

Adam M.

 

[Dink]

I have an 85 E and the footpegs are solid mounted, no rubber dampening.

Earl

Earl ALL 1150 footpegs are rubber mounted BTW.
Dink

 

[earlfor]

Dink, I think I need to clarify my response. On all GS models (that I have seen anyway) , the bolts that hold the footpegs are fitted through a rubber isolation bushing that inserts in the mount bracket. My 1150 is this way too.
From the previous discussion, I had assumed that due to vibration levels, the claim was that additional rubber dampening was added to the 1150 footpegs. There is not, but yes, there are rubber bushings. The footpegs on my 1150 and 750 are mounted in the same manner.

Concerning vibration levels, (anyone), is there any way to determine if you have an 1100 crank or an 1150 crank with only the cylinder head and barrels/cylinder removed? In working on mine, it is obvious someone has had it apart. I'm wondering if mine is as smooth as it is because something was changed.

On another note: (probably not worth starting another thread since we're already talking 1150's) In removing the cylinder head, there are 8 studs with copper acorn nuts and copper washers. The copper washers are 10 mm Inside diameter and 18 mm outside diameter and about 2.5 mm thick.
(that would be about 3/8" x 3/4" x 3/32") Anyway, when I removed the acorn nuts, most of the washers were stuck to the nuts. I put them in a tray and removed the cylinder head. On separating the nuts and washers and counting loose ones, I have 7 washers. I should have 8. I did not hear anything drop or fall when removing the cylinder head. BUT......I am not sure if there were only 7 and one was missing, or if I may have unknowlingly dropped one. At that point, the only possibility is if the 8th washer was there, it had to have dropped down the camchain tunnel.
I've since removed the cylinders and camchain fiber guides, and searched.
It appears the camchain tunnel at the crankshaft sprocket area is not wide enough for a washer that diameter to lay flat in the bottom. It also appears that there is not clearance under the sprocket for the camchain and a large washer. I've turned the engine over by hand about 30 times and everything is smooth and silent. I've also pulled the oil pan off for a look see. I find nothing. There is a plate underneath the crank cam sprocket, so it appears nothing as large as an 18 mm washer could go through. Where could it go? Unfortunately, I am not sure I ever had that 8th washer. Its driving me buggy.



Earl

I have an 85 E and the footpegs are solid mounted, no rubber dampening.

Earl

Earl ALL 1150 footpegs are rubber mounted BTW.
Dink

 

[Dink]

Earl it must have been absent, if it dropped you would have found it by looking where you have. There are supposed to be eight washers.
Dink

 

[earlfor]

Thanks loads Dink. I have literally spent hours with a small fiber optic light fished into every corner of that cam chain tunnel while looking through a big magnifying glass. Even so, I know when I get it back together and press the starter button for the first time, I'm gonna be sssss scaredddd.


I believe the cylinder head has been off the bike at least twice before. Two of the aluminum seating surfaces that should be covered by a copper washer have circular gouges in them. That can only be caused by tightening an acorn nut without a washer. A flat washer doesnt gouge when a nut is tightened on top of it. Since two surfaces are scored and I'm missing one washer, that would indicate the head has been removed twice.

Its also finally came to me why I had a dark spark plug problem on the #2,#3 cylinders some time back. I found the #5, 1,3, and 7 (in the torque sequence) headbolts were set with insufficient torque. Apparently, the mechanic didnt bother using a torque wrench. I had an internal oil leak on the headgasket and the #2.#3 cylinders were su cking oil into the combustion chamber. Not enough to notice the bike using excess oil, but it was enough to darken the plugs. Now, I know why synching the carbs, changing jetting, checking voltage, timing, valves, etc did not solve the problem. Damn!, I hate shoddy mechanics.

Thanks again Dink.

Earl

Earl it must have been absent, if it dropped you would have found it by looking where you have. There are supposed to be eight washers.
Dink

 

[kz]

Would you be kind enough topass some information about your new engine ?
according to comon knowledge bigger engine should be vibrating more, not less.

Adam M.

Hi Adam,

My conclusion is that the the bore of the engine has nothing to do with the vibrations.

I refurbished the crank at the same time I increased to 1197 and the vibrations decreased.

The compression with the 1197 went to high and the engine was knocking badley. :evil:

Well, started all over again with the same engine, mounted new pistons, this time 1327, did also replace the "cylinders" because it was not possible to drill that much otherwise.

As I now mounted the same engine again the vibrations are pretty much the same as with 1197 bore, meaning better than ever.

I belive the reason for that the vibrations are better, is the crankoverhaul and not because I have a bigger bore.

/Karl