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Hi folks,

My 86 GL1200i has developed a very coarse vibration at around 2500 rpm over the past three weeks. It is worse under load both accelerating or engine breaking and doesn't seem related to transmission or running gear (does the same in neutral and with clutch disengaged) any thoughts greatfully received.

Extra info, high milage (206,000miles) runs like a dream except the vibration, starts first time, petrol consumption and performance unchanged, cam belts done last 20,000 ago, no oil burning

Many thanks

Bob
 

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It sounds like you've already ruled out the engine and gearbox. If you are gt#etting the vibes in neutral and clutched in, I'd sayyou should be looking at the driveshaft UJ. When that wears you can get terrible vibration.
 

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Thanks Joe,

What I mean't to say was that the vibration occurs with the engine running whilst it is parked up in neutral, comes in as the revs hit 2500rpm, it is worse however with the bike running when the engine is under load, do you think it can still be the drive train?

I was wondering if there are any engine internals which are known to cause this, funny thing is, the vib dissapears once the ol girl gets up to about 3000 rpm and is good as gold after this



regards Bob Saunderson
 

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1st off, welcome to the forum. With that many miles on your friend, when was the last time you checked all the engine mounts. Just a thought...
 

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Check the torque on all engine mounting bolts.My Clymer manual says that is the #1 place for vibes to show up.
 

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Throw a timing light on. See if it winks out at the problem speed. Vibes are caused when the crank is out of balance (bearing hanging up or combustion forces not equal) or something in a valvetrain seizing or clutch basket bearings bad. The rest of the system is disconnected through the clutch. That it only shows at 2500 doesnt sound like oiling system, pressure would be less as speed decreases, not as it increases. But with that many miles, an oil pressure test wouldnt hurt. Can do a cheap one by letting it idle then dropping the idle speed slowly and see if the light winks on above 400 RPM.

3 places to listen to the internals 1.) oil fill cap 2.) timing mark access plug 3.) stator drive bolt plug

If you go to wits end without finding it, make a recording and Email it to me, I can try to calculate the vibration frequency and make an educated guess as to where its coming from.
 

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Hi Bob,

something else to check is that one of the coils may be failing pull the plug caps, front cylinders then rear see if it makes a differance to engine note,

I've just had a similar problem with a broken primary wire to a coil. ( Miss fireing under load)
 

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Pull a compression test of all 4 cylinders.. A vibration can be caused by just about anything from a loose wire, fastener, engine mount, weak cylinder, fuel feed, spark plug.. The list goes on and on..

By process of elimination, and suggestions from this board, you'll isolate the problem and be able to fix it..

With the cylinders all up to the correct compression, the engine is basically o.k... Look at the spark plugs,, what color are they? Is one or two a different color than the rest? Did this vibration just happen, or has it been coming on for a while? Secondary ignition systems can break down at certain rpms, causing a misfire in one or two cylinders which would cause a vibration... Keep digging and keep us posted on what you have for specs...

Welcome to the nest. :clapper:
 

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Thanks very much folks, what a fantastic forum, you've certainly given me some thoughts to get on with. I imagine I will be spending the next week of evenings in the workshop, and will work through things one at a time.Hopefully I can share some of my thoughts in answer to other peoples annoyances as well:)

all the best Bob
 

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otagobob wrote:
Thanks very much folks, what a fantastic forum, you've certainly given me some thoughts to get on with. I imagine I will be spending the next week of evenings in the workshop, and will work through things one at a time. Hopefully I can share some of my thoughts in answer to other peoples annoyances as well:)

all the best Bob
Hello Bob and everybody!
I also have an 86'SE-i whith most likely the same problem. Only difference I have the vibration between 2000 and 2500rpm. Higher the gear and heavier the load = worse vibration. Once it goes over 2500rpm it's smooth as an angel. I'm pretty sure
it's no misfiring because there's no lack of power during vibration. The mileage is 63000. So, I really hope that you
Bob or anyone might know what the problem can be.
(Please forgive my bad english, I'm from Norway)
Best regards from a hopeful Norwegian, Larsernz.
 

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:waving::waving:Welcome to the Best Goldwing Website in the Known World, larsernz!:waving::waving:

If the problem is the same in both bikes, it kinda eliminates carbs on Bobs since larsenz' bike has fuel injection. The fact that Bob reports vibration on engine braking too would seem to indicate something mechanical amiss since neither the fuelor ignition system would matter all that much when the rear wheel is turning the engine which at that moment is basically only pumping air and not generating any power. I'd agree with JDuggan and take a look at the drive line.

Larsenz problem sounds more ignition or spark plug problems to me, he's experiencing the problem only under high engine load if I'm reading him right, when the engine is turning relatively slow and pulling hard. Not quite lugging but loaded heavily. This generates high cylinder pressures that can blow out poor spark plugs or weak ignition. It only takes a little miss under high load to generate some vibration, you can really feel it in flying machines, a shudder that will quit with leveling off and easing the power a bit.
 

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Hello and thanks exavid for quick reply.
Yeah, you're right about this must be the best GW forum in the world!!!
Well, back to my bike. It's not only under high load I'll get the vibration, it's just much stronger then. If I hit the throttle fast when the bike is in neutral on the centerstand, I can hear/feel it too (clutch engaged or not, no difference). It's also worse when the engine is cold. I'm a quite experienced mechanic and my proffesion is technical adwiser for Peugeot, but of course, I don't have to much experience with bikes. My guess is that the problem is somewhere in the gearbox, but I'm far from sure.. Normally if it's a bad bearing, large clearance or so, the problem should
accour more or less all over the rpm-range. So that's why I hoped somebody ells have had a simular problem and knew what it was. Anyway, I guess I have a total stripdown coming up.... Whatsoever, it's really nice to search this forum and find so many good hints and tips, Thank you all!

Best regards, Larsernz
 

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otagobob wrote:
Hi folks,

My 86 GL1200i has developed a very coarse vibration at around 2500 rpm over the past three weeks. It is worse under load both accelerating or engine breaking and doesn't seem related to transmission or running gear (does the same in neutral and with clutch disengaged) any thoughts greatfully received.

Extra info, high milage (206,000miles) runs like a dream except the vibration, starts first time, petrol consumption and performance unchanged, cam belts done last 20,000 ago, no oil burning
Bob, if it doesn't seem related to transmission or running gear and will stillvibrate in neutral you might have a rotted out or cracked exhaust system. If that lower exhaust crossover between muffler sides is broken or cracked it will vibrate more than normal.

Make sure you haven't bent an exhaust pipe or pipe mount also.

If it still seems like engine internals try running the bike down the road in 3rd gear above the vibration point, then hitting the kill switch and letting it cost back through the offending rpm. If it quits vibrating suspect a carb sinc problem or one carb that's not pulling it's share of the metering load just as the slide opens.

One cylinder that is low on power will cause a vibration when throttling up.

Any idea when the vibration started? Was it a gradual introduction or did it appear all of a sudden? The more history you can give us on the problem and when it started the closer we can get to the problem.



Twisty
 

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larsernz wrote:
Hello and thanks exavid for quick reply.
Yeah, you're right about this must be the best GW forum in the world!!!
Well, back to my bike. It's not only under high load I'll get the vibration, it's just much stronger then. If I hit the throttle fast when the bike is in neutral on the centerstand, I can hear/feel it too (clutch engaged or not, no difference). It's also worse when the engine is cold. I'm a quite experienced mechanic and my proffesion is technical adwiser for Peugeot, but of course, I don't have to much experience with bikes. My guess is that the problem is somewhere in the gearbox, but I'm far from sure.. Normally if it's a bad bearing, large clearance or so, the problem should
accour more or less all over the rpm-range. So that's why I hoped somebody ells have had a simular problem and knew what it was. Anyway, I guess I have a total stripdown coming up.... Whatsoever, it's really nice to search this forum and find so many good hints and tips, Thank you all!

Best regards, Larsernz
I'm surprised the vibration is present even on the sidestand with the rear wheel stopped. It's hard to imagine what could cause the vibration internally from the engine or transmission that wouldn't cause a catastrophic failure. The fact that is smooths out above and below the critical rpm does usually eliminate a badly worn bearing. Crankshaft and lower bearing problems are rather unusual in these engines.

It's a long shot, but have you pulled the timing covers off and had a look at the timing belts? Slack from a bad idler or a stretched belt could cause an odd resonant vibration.

:waving::15red::waving:
 

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Assuming the compression is within specs., and there is no abnormal engine noise like rapping, knocking or grinding, and the oil pressure is where it should be, balance the carbs. If you still have the vibration running the engine in neutral, it could be a x-fire of the spark plugs.. With that many miles on the engine, the plug wires could be leaking voltage. I had to deal with it on early Ford v-8 engines due to the way the plug wires were routed.. In a short period of time, owners would complain of a skip and vibration in the engine when parked... It came and went either in neutral or under a load and no one could figure it out. It was two cylinder plug wires just routed near each other and arcing would occur under certain conditions.. Re-routing the wires made the vibration & skip go away... Perhaps it's time to replace the plug wires after all these years and miles..
 

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Hello again exavid
No, I haven't checked the timingbelts yet, but I sure will do
now... I'll let you know when I have checked. Thanks for the tip!
Larsernz:waving:
 

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To anyone reading; are there any balance shafts within the 1200 engine?

With the sort of milage quoted at the start, any bearings in or around that kind of area may be suspect.

With the vibration "driving itself out", as with a steering wheel wobble on a car, I would summise something like shaft/bearing.

Just a thought. Nasty, I know; but possible.

Phil.
 
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larsernz wrote:
(Please forgive my bad english, I'm from Norway)
Best regards from a hopeful Norwegian, Larsernz.
Hey Larsernz :waving: Your very welcome to the best Goldwing forum on the net.:clapper: Your english is very good, i wish i could speak Norwegian half as good. The best ican sayis "Takey mekey bra" and thats all spelt wrong. :crying:

:walker: :18red: :walker:
 

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Redwing. wrote:
larsernz wrote:
(Please forgive my bad english, I'm from Norway)
Best regards from a hopeful Norwegian, Larsernz.
Hey Larsernz :waving: Your very welcome to the best Goldwing forum on the net.:clapper: Your english is very good, i wish i could speak Norwegian half as good. The best i can say is "Takey mekey bra" and thats all spelt wrong. :crying:

:walker: :18red: :walker:
Hello redwing!
Thank you! It is a great forum. He he, your norwegian beats me.... you got "bra" right (means good), but "takey makey" must be some new norwegian words that I've never heard..!
:D Larsernz
 
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