XS 1100 Special Engine Knock or clacking sound Help?

[dolphans1]

I have a difficult question to ask about my 1979 Yamaha XS 1100 Special and it centers around a "knock" noise I feel I am hearing, so I made this YouTube video to see if I may gain some clarification to it.

I recently rebuilt the carbs, but never had them synched, however, when bike runs at high speeds and higher RPM's that sound goes away.

My bike has almost 11,000 miles.

https://www.youtube.com/watch?v=YXQY1IXhQbE

Thanks for any input or suggestions....

[TopCatGr58]

Can't access video!

Hey there,

We can't access the video, it's PRIVATE!!! You need to edit it to make it public!!

T.C.

[BA80]

You've gotta change your privacy settings on youtube or load it into a Photobucket account

[dolphans1]

Hey there,

We can't access the video, it's PRIVATE!!! You need to edit it to make it public!!

T.C.

Thanks for letting me know, let me see what is going on.

[dolphans1]

I just made correction and I did not realize we had to make it a public video, I hope it shows up.

Thanks Again for letting me know.

d-1

[BA80]

Sounds like an exhaust leak. Take a piece of hose, vacuum hose works well, put one end in an ear and run the other open end around the exhaust pipes where they connect to the engine and you can find which pipe is leaking.

New exhaust gaskets should take care of it if that's what it is.

[dolphans1]

Sounds like an exhaust leak. Take a piece of hose, vacuum hose works well, put one end in an ear and run the other open end around the exhaust pipes where they connect to the engine and you can find which pipe is leaking.

New exhaust gaskets should take care of it if that's what it is.

You mean like a vacuum cleaner hose to like a shop vac?

Thanks for advice.

[BA80]

Ummmm........no. I mean vacuum hose like to hook to the vacuum ports on the engine. Black rubber hose about half the diameter of your little finger.

[MaximPhil]

Sounds like an exhaust leak. Take a piece of hose, vacuum hose works well, put one end in an ear and run the other open end around the exhaust pipes where they connect to the engine and you can find which pipe is leaking.

New exhaust gaskets should take care of it if that's what it is.

I agree Greg. I should know as i have experienced this many times.
Dolphans, get some PB Blaster penetrating oil available from Walmart
and soak those nuts before you attempt to undo.
Gaskets available lots of places like here http://www.partsnmore.com/parts/yamaha/xs1100/?filters[fitting]=custom
about 1/2 way down the page.
Be sure to remove all the old gasket. Check manual for torque when
re installing. See forum thread about how to replace broken studs if you do not have a torque wrench with a low enough setting

Phil

[ViperRon]

I agree sounds like exhaust but also while you are at it you have old style cam chain adjuster. You should perform the cam chain adjustment if you do not have a manual search threads there are several downloads.

[BA80]

I heard that too Ron, I was just trying to stick to the subject.

[dolphans1]

Just a follow up to this post, it appears the sound may be caused by a vacuum leak from the carbs.

I took it to a bike shop today and he plugged a carburetor synchronizer and we he attached all 4 hose to the sync gauge and started the bike, and plugged the hose leading to the crank case, the knocking sound went away.

The carbs were all dead on synced , but I do not know how all the original vacuum hoses should be connected to the bike, since the original owner had air pods on the bike and I went bike to the original air cleaner.

I know there are 2 vacuum hoses that hang down, but I am not sure where I would put those.

Does anyone have a drawing how these hoses should be connected?

[dolphans1]

Just a follow up to this post, it appears the sound may be cause by a vacuum leak from the carbs.

I took it to a bike shop today and he plugged a carburetor synchronizer and we he attached all 4 hose to the sync gauge and started the bike, and plugged the hose leading to the crank case, the knocking sound went away.

The carbs were all dead on synced , but I do not know how all the original vacuum hoses should be connected to the bike, since the original owner had air pods on the bike and I went bike to the original air cleaner.

I know there are 2 vacuum hoses that hang down, but I am not sure where I would put those.

Does anyone have a drawing how these hoses should be connected?

[motoman]

Just a follow up to this post, it appears the sound may be cause by a vacuum leak from the carbs.

I took it to a bike shop today and he plugged a carburetor synchronizer and we he attached all 4 hose to the sync gauge and started the bike, and plugged the hose leading to the crank case, the knocking sound went away.

The carbs were all dead on synced , but I do not know how all the original vacuum hoses should be connected to the bike, since the original owner had air pods on the bike and I went bike to the original air cleaner.

I know there are 2 vacuum hoses that hang down, but I am not sure where I would put those.

Does anyone have a drawing how these hoses should be connected?

Should'nt be any hoses hanging down as you say. The sound your hearing is likely from the vaccum advance hose hooked up incorrectly. That hose, which comes from left-side ignition cover goes to #2 carb itself, not the intake boot nipple.
I don't have the Special, so don't have the 'octy'. Another member here who does can better explain or show pic of the hose configuration on the Specials.

[BA80]

There should be vent hoses (kinda look like vacuum hoses) running from the battery and the middle drive and hanging down by the middle of the front of the swingarm under the bike.

If you still have the octy there will be a hose from the diaphragm to the #2 intake boot. The vacuum advance hose running from inside the left engine cover goes to the vacuum port on the front of the #2 carb.