Project "walrus" Yam XS 750

This may help you, taken from the Triples site in 2008
I should add that some after market base gaskets have been a problem.

To replace the base gasket, you have to pull the jugs...
But....there is a cheap way to try to fix it that often works, and is really easy.
First clean the area where the leak is with brake parts cleaner. Dry the area completley with compressed air.
Get a bar of Ivory soap (use Ivory brand...it works the best). Using heavy pressure, rub the bar of soap over the leaking area, forcing the soap into the leak. Go over the area several times, to make sure you get good peneatration into the leaking area.

I know this sounds dumb, but I have sealed leaks on several different bikes this way. Besides...all you are out is a little time, and the cost of a bar of Ivory soap, if it does not work.
In most cases, this will seal this kind of leak for several months or more....if it starts leaking again, just clean the area, and re-apply more soap.

Short answer (and you won't like it): No. Pull it apart and do it properly.

Could also just be the cam chain tensioner leaking and running down the front of the block.

Re: Project "walrus" Yam XS 750

Ryan Stecken said:

As a german speaker its a always interesting to see alignments in your language is it the same with you and german?

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alignments? there are quite a few technical terms borrowed from germany in sweden
about the leak - did you check the head torque? they rarely come loose but worth a check.

hillsy said:

Could also just be the cam chain tensioner leaking and running down the front of the block.

Click to expand...

I´m 100 per cent sure it comes from the bottom gasket.
The oil drip starts at the bottom gasket and makes its way down to the downpipes and burns there.....AAAARGGHHH i´m so frustrated...thought this thing is finally running now....

Data, which are the cylinder head screws in the diagram?do you mean the screws with number 35?

Cheers!

Headbolts: #32 in the picture

Interesting that there's a seperate gasket for the cam chain tunnel (#27). It's more than likely that if it isn't the tensioner.


Is there a visible gap there between the block and crankcase? I'd try some JB Weld or epoxy if there is - it's not an oil galley, so you won't block anything.

Re: Project "walrus" Yam XS 750

Yes its not worth taking it apart for. Just go over the headbolts, in the correct sequence and check that all is well there before doing anything else

Re: Project "walrus" Yam XS 750

Look at this on eBay http://www.ebay.com/itm/172508264620
i would try this but it doesnt ship to sweden..

I'll let Mr. Stecken post the pictures, but we had a more than thorough check up of the bike and the base gasket is pretty much foo-bared. It most likely has to do with some damage on the mating surface between engine block and cylinder-base - exactly were the spot for prying it up is. What's the odds we'll find screw-driver marks there?

Re: Project "walrus" Yam XS 750

Life goes on.

I will try the trick with a bit of Dirko HT sealant on the spot were the oil seeps out.If it doesnt work it doesnt work.

In the meantime I'm preparing my 74 hp head which I will use anyways sooner or later.Blasting,painting,fitting new viton valve seals,lapping the valves...

Really frustrating when the bike comes together abd runs fine and ready for MOT and this happens (the leak only happens when the bike is really hot so I couldnt check for that before)....





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Re: Project "walrus" Yam XS 750

This weekend I invested my workshop time onto my Yamaha RD.MOT coming up,my exhaust is too loud...blablabla...however took some time and cleaned the gasket surface.
This is taking a lot of work...what a chunk of metal

Yesterday I took some liquid gasket maker and after degreasing put it onto the cylinder foot of the XS...lets see if this will work.
MOT will be done this friday, hope I´ll pass. ;D

Oil leak from that place is apparently an know "child disease" with the XS. I have an XS 750-2D 1977 (1T5...) with the same problem. I just let it be for a couple of years and cleaned it when necessary regularly checking the oil (never a problem here though). Now when its apart I need to deal with it though.

On the danish page, www.rider.dk you can find information about the tripples in danish ofc. They have an passage about this oil leak, ill translate:

Danish passage:
"Firkantet gummitætning ved cylinderfod
For XS750 er det ikke ualmindeligt at finde oliespild fra området omkring denne pakning. Det må anses for sandsynligt, at en del motorer har en lidt for dyb rille til den firkantede gummipakning, som måske heller ikke er høj nok. På XS850 er gummitætningens profil ændret fra et nærmest trekantet til rund. Rillen er tilsvarende mindre dyb.
Ifølge Yamaha skal rillen for XS750 være mellem 1.9 og 2.6 mm dyb. Er der problem med oliespild dette sted kan sagen undertiden afhjælpes ved at klippe en 0.5 mm papirspakning til i samme facon som gummipakningen. Papirs- og gummipakning smøres med siliconegummi og placeres i rillen. Papirspakningen nederst og gummipakningen med den skarpe kant opefter. På XS850 er der sjældent problemer dette sted. Lidt silikonegummi kan den dog med fordel smøres med."

translated:
"Square rubber seal at cylinderfod:
For XS750 is not uncommon to find oil spills from the area around the package. It is considered likely that some motors have a little too deep groove to the square rubber gasket that may not be high enough. On XS850 the rubbersealing is changed from an almost triangular to round. The groove is correspondingly less deep.
According to Yamaha, the groove for XS750 be between 1.9 and 2.6 mm deep. If there's a problem with oil spill from this place the matter may sometimes be corrected by cutting one 0.5 mm paper packaging in the same shape as the rubber gasket. The paper package and rubber seal are lubricated with "silicone rubber" (silicone based lubricant?) and placed in the groove. The package of paper at the bottom and the rubber gasket with the sharp edge upwards. On XS850 is seldom a problem this place. Try using a little silicone lubricant."

Re: Project "walrus" Yam XS 750

I had an updated big round section seal in my gasket set, feels good.

So long time no hear guys....
The XS is up and running on thr streets of Vienna...
Got that thing MOT'd with no real problems,found a workshop which is pretty easy on youngtimers so my RD got its MOT there too

After some days of riding with the cylinder foot leak I checked the cylinder head screws...the PO forgot the even screw of them in...there were on there completely loose...so I brought then carefully to the right torque and now the oil loss is minimal,no oil on the headers anymore.
Changed my bars the higher more comfortable ones,now I need new longer cables refitted.

One problem however I encountered is that the bike makes 'cracking' noises (like when one misshifts on a car) in first and second gear in the 3rd and other gears the problem gets smaller.
When I revv the engine to the 'right' revvs the sound dissappears...
Could this be a maladjustment of the clutch,normally the gears are independent from the clutch arent they?

Thanks in advance!

Re: Project "walrus" Yam XS 750

datadavid said:

Yes its not worth taking it apart for. Just go over the headbolts, in the correct sequence and check that all is well there before doing anything else

Click to expand...

datadavid said:

alignments? there are quite a few technical terms borrowed from germany in sweden
about the leak - did you check the head torque? they rarely come loose but worth a check.

Click to expand...

Ryan Stecken said:

So long time no hear guys....
The XS is up and running on thr streets of Vienna...
Got that thing MOT'd with no real problems,found a workshop which is pretty easy on youngtimers so my RD got its MOT there too

After some days of riding with the cylinder foot leak I checked the cylinder head screws...the PO forgot the even screw of them in...there were on there completely loose...so I brought then carefully to the right torque and now the oil loss is minimal,no oil on the headers anymore.
Changed my bars the higher more comfortable ones,now I need new longer cables refitted.

One problem however I encountered is that the bike makes 'cracking' noises (like when one misshifts on a car) in first and second gear in the 3rd and other gears the problem gets smaller.
When I revv the engine to the 'right' revvs the sound dissappears...
Could this be a maladjustment of the clutch,normally the gears are independent from the clutch arent they?

Thanks in advance!

Click to expand...

Glad and not surprised to hear the bolts were loose. These suckers have sharp little vibes knocking every nut and bolt loose eventually.
Sounds like you still have clutch drag. Gears are clunkier than modern bikes but quiet when everything is working right. Mine is very smooth now, and its all old parts in there except the springs.

Re: Project "walrus" Yam XS 750

Btw i loctited the screws holding the clutch springs. Torque value seemed too low to retain them securely and tightening more risks stripping them.

I might have had the same sound on my bike. Hash and raw. Usually when the bike was warm and in lower rpms but disappeared when giving more throttle. I dont know if this is what caused the sound, but I saw that my primary chain gnawed on the inside of the engine cover. Could it be that? Loose primary chain? Seems to be a known problem.

Great to hear she is on the road.
The shaft drive also adds to the amount of lash in the drive train, so there is plenty of room for clunks and rattles.
Cheers
Tim