Hi Guys, noob here...

Greetins,

really cool forum, I was given a old xj and so im going to try and make it roadworthy. I got a new batt, new plugs, new gas, oil, tires, brake pads, all installed. it has 2 problems at this point, one that im pretty sure
we can sort out easily enough ( rough cold running and bit of a miss )

but its the second problem im not sure of as i dont know whats behind all those covers on the engine. the trans works fine, engine itself works fine,
but thre is a whining or howling kind of noise coming from the front lower part of the engine , behind those round covers with the yamha spider wheel on it. whats in there ? is that some kind of clutch or part of the tranny or what ??

thnks much ! oh ! its a 85 750 water cooled

 

wow.. 11 views and no replys, sorry i asked such a hard question...

 

Sorry Yankee, we can be a skittish lot. Welcome to you and well met. A free bike is a good place to start. I'm not up on water cooled X bikes but I know others will wander in and offer their observations. My best advice is to get your hands on a maintenance manual (Chacal is our site parts guru, he'll likely be your best source). You will learn much from it, be able to identify parts of your machine and can give better descriptions of issues you have. Worth every penny.
Welcome once again.

 

can we take it that the noise is from the left side of the engine as you sit on the bike? And Hi.

 

I'm no expert but I'll take a shot at it,

Those covers you discribe are refered to, in the parts schematic
Under the section crankcase cover as Oil pump cover 1 (left side
of motor) oil pump cover 2 (right side) My bike is an 82 750 and
I couldn't find a part break down of your bike so referencing
my bike.
Found under the left side cover is the pick coil- governor.
Also the crankshaft ends are located there under those covers.
I've not had the right side cover off so I don't know whats under there except for the crank end

 

Hi Guys,
As your sitting on the bike, its the right side,
thnks for the help, it honestly sounds louder behind the right side cover,
the left side sounds pretty good. its the weirdest noise, kind of like
mechanical howling

DOES EVERONE NOT HAVE THESE ROUND LOGO COVERS ?

IM ALSO WONDERING, SINCE ITS WATERCOOLED, DOES IT HAVE A WATER PUMP ?

 

Hi Guys,
As your sitting on the bike, its the right side,
thnks for the help, it honestly sounds louder behind the right side cover,
the left side sounds pretty good. its the weirdest noise, kind of like
mechanical howling

DOES EVERONE NOT HAVE THESE ROUND LOGO COVERS ?

IM ALSO WONDERING, SINCE ITS WATERCOOLED, DOES IT HAVE A WATER PUMP ?

 

on my bike there is nothing behind the right cover. just a seal that blocks off the end of the crank. you should be able to remove it without much worry to see for yourself. just in case, wait for some water cooled guys to chime in first.

 

in there is the main bearing, if that is in distress stop the engine before the con rods crochet you a new beanie.

 

Here's something we can do now in this marvelous New Age ...

Have someone who has the goods make a 30-second video of it and be sure we can hear the noise over the exhaust ... even if you have to practically put the camera on the bike!

XJ-Tube!
Let's do it!

 

Not a clue on the mechanical issue of it outside what has been mentioned already, but to answer one question you have... no, we don't all have the logo round covers. That started on the 85 model year and I've noticed that the majority here have 80-82 models (though there are plenty as well with newer models). Anything prior to that had no logo or the Yamaha lettering on it.

 

On the right side, the larger cover is the clutch, the smaller round one all the way forward is the "vanity cover" over the RH crankshaft end seal. That's the one with the "star" pattern to it on your bike. Wizard is right, nothing behind there except the RH end of the crankshaft and the main bearing. Are you 100% positive the noise is coming from there? There are components behind the larger (clutch) cover that can have issues and cause strange sounds (like the "oil pump cover" coming adrift.) Take a long screwdriver, wedge the end of the handle in your ear and use it as a stethoscope. You should be able to pinpoint the source of the sound that way, and we'll go from there. And yes, your bike does have a water pump, although exactly where it is wasn't clear from the Yamaha parts fiche. Appears to be on the LH side somewhere but I could be full o' poo on that one...

 

I use this trick often, it works great.
You can use a hammer handle, broom stick, anything solid.
Pinpointing a noise on a V8 it has saved me time and money.

 

Ha! Thanks much guys, yea the diagrams dont show the round vanity cover for the end of crankshaft, or even the end of the shaft sometimes, so ...... I did put a metal rod to the area and pin down its coming from there, ... however the noise decreased by half or more once the bike warmed up, I think most times we hear bad noises there after a bearing has trashed, its possible i might be hearing one in progress of going bad..

But, im going to pull her out of the garage tommrow morning and fire it up and double check the noise with a rod agian.

AND MAKE A RECORDING

 

Guess one cant expect a free bike to be perfect.... this one has 2 problems, one of which a good carb rebuild at Wild Georges will fix,
the other is this funky noise. The rest of the bike is pretty nice
considering its half as old as I am...LOL

Thanks for the hint on where the water pump is, Water Pumps can
make a hell of a noise when they go bad.. ill check that too..