New Cylinder base gasket already leaking...

[DougXS2]

I just went thru the entire top end of my xs2 and put new base gasket, head gasket, cam chain, valve guides, seals, etc.

and everything runs great but with only about 20 miles on it....the new base gasket is already weeping oil off the back four studs.... the fronts are completely dry.

everything was torqued to spec so I'm a little reluctant to just put a wrench on and crank them down more....but what to do?

 

[scabber]

The head needs to be torqued several times after you put it back together. Put a wrench on it and torque it.

 

[weekendrider]

+1 on scabber's advice

 

[vr3506]

Did you put the 2 o-rings on the cilinder, the ones that are situated at the base gasket?

 

[5twins]

How much torque did you use on the 8 large acorn nuts? The Yamaha factory spec of about 26 ft/lbs is not enough. Most of us go about 30 ft/lbs on those 8 nuts.

 

[vr3506]

3,5-3,7 kg/m

 

[DougXS2]

yes....on the two cylinder o-rings. got two new ones from yamaha.

on the 8-acorns...I went to 32 ft lbs on those.

also got 4 of the new rubber outter washers but from reading it sounds like those should be switched to bronze? I couldnt understand how you can get an accurate torque reading with rubberized washers in there?

 

[DougXS2]

so should I just plan on retorqueing the head every xxx miles?

200, 500, ???

 

[blackbetty]

I did mine after every heat cycle for the first 4-5 rides.

Then I would do it every 2-300 miles.

Leak free w copper gaskets prepped with kopperkote.

 

[5twins]

You can get an accurate torque reading on the rubber washers, it's just that it doesn't stay there for long. Those 4 outside acorn nuts will constantly loosen up on you. The 4 outside studs flow oil so you need a soft washer under the acorn nut to seal it. The rubber ones are too soft. A brass or copper one is soft enough to seal but hard enough to hold the torque setting. Change the rubber ones out.

Yes, after a top end rebuild, you'll need to do several re-torques in the 1st few hundred to a thousand miles. First couple times, you will probably find quite a few loose fasteners. That should taper off as all the new gaskets get fully compressed. Even after things do stabilize and stay tight, it's not a bad idea to check the head torque once a season. I do mine every spring.

 

[DougXS2]

good to know.

was just hoping to have gotten rid of all or most of my leaks with all the new gaskets!

I'll keep torqueing and cleaning.

 

[peanut]

I'm reading this with much interest as i'll be building my engine for the first time shortly

Sounds like these bolts and nuts give a real problem . Is it worth replacing the stock studs and nuts with a better quality item like stainless steel or something ? Surely owners that prep these engines for racing don't have to go through all this retorquing every 5 minutes ?

 

[xjwmx]

The rubber ones are too soft. A brass or copper one is soft enough to seal but hard enough to hold the torque setting. Change the rubber ones out.

My rubber coated steel ones ones have lasted for 46,000 miles so far with no leaking. No retightening since at least 17,000 before which who knows.

I suspect what's going on if there's a lot of leaking and loosening around here is that the gaskets are the problem.

 

[650Skull]

How many times did you go around the head when you were torquing it.

 

[peanut]

I just did a search on this problem out of interest and Bob B over on 650motorcycles.com talking about this problem says ''Heavy duty 10mm X 1.25 race studs that have rolled threads and are a full 10mm diameter across the stud length get torqued to 40 ft lbs.' so interestingly enough it looks like I was thinking along the right lines

http://www.650motorcycles.com/CopperWashers.html

 

[DougXS2]

I initially torqued the head in two or three passes, working up to 32lbs.

then went around a last time to double check it.

the gaskets are new from mikes, so I doubt thats a problem.

 

[5twins]

That new base gasket is supposedly treated with heat activated sealer. There have been a couple reports of it leaking at first. Maybe it just needs some run time and to get good and hot before the sealer kicks in. I've used a couple of them so far and have had no problems but I do multiple re-torques in the 1st few hundred miles. My 1st re-torque comes after letting the freshly assembled motor sit over night, before it's even been started.

 

[DougXS2]

haha. now you tell me!

 

[hooktool]

It also may leak from somewhere else and appear to be the base gasket. Oil can wick up, down and across and sometimes show up far from where it came.

John

 

[DougXS2]

I wondered about that but it appears dry about that....