Killer vibration

[oldschoolorange]

My 81 gs400 with an 89 gs500 engine has a really bad engine vibration.
I found it had actually shook loose 2 of my motor mounts. Those are now fixed, I removed the valve cover but found that I have hydraulic lifters so I can not adjust the valves however I do have some lash there. The only thing left for me to check is the carbs and I will do that tomorrow. I should also note that I only really noticed the engine vibration after the bike was dropped on its side, I have already taken the cam caps off and inspected them for scoring but there is none.

Has anyone ever seen the balance shafts in these engines skip a couple of gear teeth, or a harmonic balancer let go? This is driving me nuts and getting expensive as I have gone through 2 headlights this week

[renobruce]

Out of synch carbs can cause ALOT of vibration. I would start there, especially if it is not mis-firing.

[jbs80106]

Aside from stuff coming apart...

U can pretend you have a 'well tuned' V-twin like the HDs!!!! \\/

[argonsagas]

Out of synch carbs can cause A LOT of vibration. I would start there, especially if it is not mis-firing.

That would be my advice, too.

Since the problem began after the bike fell, look for something bent, or out of place, as well as out of synch.

[chef1366]

Synchronize those carbs! Good advice.

[petelardo]

The GS500 engine does NOT use hydraulic lifters; the valves are a shim-over-bucket design, which is different from threaded adjusters...

Information about the GS500 can be found here:

http://cgi.stanford.edu/~sanjayd/gs500

That link will take you to a wiki specific to the GS500... basic valve information here:

http://cgi.stanford.edu/~sanjayd/gs500/Maintenance/CheckValves

This link will show you a LONG video (ONE HOUR and NINETEEN MINUTES!) on how to adjust the valves on a GS500 engine:

http://video.google.com/videoplay?docid=-2015554469142545363

Watch it, so you'll know what to expect, and what special tools and equipment you'll need. It is LONG, but thorough, and you might want to bookmark it for future reference...

Hope this helps you get those valves taken care of; as others have mentioned, misadjusted carbs can cause a LOT of vibration problems, so this link should help you:

http://cgi.stanford.edu/~sanjayd/gs500/Maintenance/RoutineMaintenance

Check these links too:

http://www.gstwin.com

http://www.gstwin.com/how_to_pages.htm

http://www.gstwin.com/adjust_valves.htm

Lastly, check out the GS500 forum here:

http://gstwins.com/gsboard/

Good luck with this; keep us posted on your progress, and ask any questions you might have if you need clarification about any of this.

[oldschoolorange]

wow thanks for the info Pete.

As for the carb adjustment I think I will do it tonight and let you all know if it fixes my problem.

P.S. I have been on several HD's and they don't shake this much lol

[chef1366]

If it's shaking that much it might be a timing issue.

[oldschoolorange]

Yeah the carb cleaning/ re sync had no effect at all so the problem is defenetly internal.

chef1366 I am assuming you are talking about a mechanical timing issue as the electronic pickup can not be moved, I guess it is possible that the timing chain may have jumped a tooth. It is just weired because the engine seems to run fine and the plugs look good. I have a bad feeling I am going to be tearing the engine apart in the near future to sort this problem out.

Oh and does anyone have a gs500 manual in pdf they can send me or a link to one. I am too poor and cheap to buy one at them moment

[chef1366]

Could be a stretched timing chain or bad cam chain tensioner.

[oldschoolorange]

Yeah I checked out the chain the other day for tension when I had the valve cover off and it seemed tight. I am going to see if I can find out how to check the mechanical timing tomorow

[chef1366]

It's going to be tight between the cam sprockets.

[txironhead]

What exactly was damaged in the layover? Sometimes the smallest things can cause problems......like a faulty clutch safety switch keeping my bike off the road for a week....

[salty_monk]

Look in the headlight bucket, you can simply unplug the bullets & bypass it, when you get the new switch you can connect it back up again.... Takes 5 mins.

Dan

[oldschoolorange]

the only thing damaged was the tank got a dent in it from the bars, besides that everything else in mint I have allready bypassed all of my safety switches since I switched my harness. I am going to check it out tonight