GS750 engine noise

[tkent02]

Were the new buckets and different in diameter from the old ones?

I have always wondered why some engines were much quieter than others.

[uk gs nut]

gs750 engine noise

I measured a couple and the difference was hardly worth it, will find out tomorrow. Thanks for your interest.
Dennis.

[tkent02]

I can't remember what the clearance is supposed to be, but I haven't ever seen any obvious wear in the bore or the bucket itself. Have noticed some engines are much louder than others for no apparent reason.
Very interesting.

[uk gs nut]

gs750 engine noise

Hello everyone, well the results are in. ureaka ! job done the noise has gone. I was doubtfull about changing the buckets but it did the trick the bike has never been as quiet as it is now. Old red 77 gets a repreve from being beheaded. Thank you to all who were showing interest.
Dennis.

[Wingsconsin]

(Just kidding)

We may need more video to prove it is fixed...

Congratulations on the repair...

[Charlie G]

Congrats! I know it always feels good solving a potential motor death sentence problem.

cg

[uk gs nut]

gs750 engine noise

Hi everyone, thought i had better post another short video of the GS750 engine sound after changing all the buckets. Could be there is a few non believers.

http://www.youtube.com/watch?v=L88Jgms7L5o&feature=youtu.be

Going to take it out for a blast tonight as its not to cold.
Dennis.

[hampshirehog]

Ahh, but did you lean it upside down to see if it made any funny noises....?

Result there and another new (to the current members of this forum, or at least the ones who read this thread) problem solved. Thanks for updating.

BTW - don't ride your bike down this way tonight - it's bloody cold!

[uk gs nut]

I may need to do the coil relay mod, and full carb dip just incase . The ride was great, but traffic was busy. Heated grips on full and still 14.1 volts on meter.

[Mekanix]

So in theory... Why ?


Just a wild guess:

Could the bucket be worn slightly and allow itself to rock side to side on the valve stem. When the cam lobe would push down on it and the bucket rock to the side, that would put the pressure on one side of the bucket and cause it to rotate. That rotation would push the cam to one side causing the knock...

Only fix would be replacing the buckets.

[tkent02]

Some of the buckets have the little tip inside to push on the valve, some don't.

I wonder if this might have something to do with it?

[uk gs nut]

I will post a picture of what i found on the buckets tonight, at work at the moment.
Dennis.

[uk gs nut]

gs750 engine noise

Well here we go, Mekanix i think your on the right track with lateral forces on the buckets. I found 2 followers with more wear marks at top and bottom but next to nothing at the waist area, measuring with my cheap digital guage i could not see any variation in diameter. What do you folks think ?.
Tried to upload a picture but did not work, so did a video.
Dennis.

http://www.youtube.com/watch?v=0gX6pXojiSg&feature=youtu.be

[londonboards]

And when you lent the bike over, oil would suppress the noise?

Greetings

[Mekanix]

I think the weight of the cams when tiped over would be holding them to one side so there wouldn't be any movement to cause the knocking.


In that video it looks like those buckets belonged to one cam, Exhaust maybe? And maybe they were in the right place for one to compliment the lateral movement of the other ?