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Jumping around a bit… back on the 14th I posted a question about retorquing the head on this bike: http://www.xs650.com/threads/head-retorque-and-brass-washers-question.52552/

I’m not impressed with how this forum does quotes, so I’m just going to copy and paste here. My original post went like this:

So I have oil leaking from the left side of my just-purchased XS650, specifically from the head gasket. It runs good, so no compression issue is evident. I saw this old thread:

http://www.xs650.com/threads/leaking-head-gasket.30135/#post-302298

The members there talk about retorquing the head bolts, which I have already been advised to try on my 1980 Honda CB650 which has a similar issue. I’m good with doing that, but the thread above is light on details, and I’m the sort who likes to have everything nailed down.

First of all, brass washers are mentioned, from Mike’s XS.  This the correct part:

https://www.mikesxs.net/yamaha-xs650-brass-cylinder-head-washer-oem-90210-10004-00.html

According to the parts fiche on CMSNL (which is the one I use all the time for my other bikes), there are 4 part no. 90210-10004 washers used, which according to Mike’s XS are the equivalent parts to the brass washers they are selling. But according to the parts fiche, there are also 4 part no. 90201-10131 washers, under the other four acorn nuts. Turns out these are standard steel washers and do not need replacing.  However, those nuts still need to be retorqued.

5twins replied to my question on the XS650 forum about retorquing with some advice on different washers that might work, and ended with this very useful rundown of the procedure:

“Yes, remove one at a time, clean and lube the threads (anti-seize), then torque. I bring them up to about 25 in a couple steps, then once all are done, go back and bring them up to 28. The only other bolts that contribute to sealing the head gasket are the 2 under the spark plugs and that little 6mm at the rear. The other smaller bolts in the top cover only hold that cover on. You probably don’t need to disturb those.”

JimD54 added a link to his engine buildup thread. Lordy, I wish I had those skills. He recommends 27 ft-lbs torque on the acorn nuts and 72 INCH-lbs on the little one at the rear. He says 14 ft-lbs on the other bolts, but the diagram he included shows 16 so I’m not sure what’s best there. 5twins didn’t weigh in on the torque for those either. Yamaha’s manual says 16 ft-lbs, so I suppose that’s the answer, and the little bolt at the rear calls for 7 ft-lbs; if I haven’t messed up the math, 72 in-lbs. is 6 ft-lbs, making JimD54’s recommendation pretty close to the manual.

SO at the moment I’m planning on going with this:

Studs/acorn nuts 28 ft-lbs
Bolts under spark plugs 16 ft-lbs
Little bolt at the back 7 ft-lbs

Here’s a diagram I made to help me remember the procedure.  I printed it out and stuck it up on my parts shelf with magnets, for easy reference while doing the job.

As you can see, I’ve revised the diagram from the Yamaha manual, reorienting it so front is down (as JimD54’s diagram is in his thread). I’ve numbered just the bolts/nuts that got attention, and included the torque measurements I chose after all the discussion I read and participated in on the forum.

… and now the job is done.

I don’t think the retorque has fixed the oil leak. Maybe, maybe it’s slowed a bit, but not stopped, nor even slowed as much as I hoped. Gah. Retorquing the head was a lot easier than I expected though. I can’t really tell if the current leak is actually the head gasket, or if it’s the base gasket, as there is so much oily crud from the head gasket to the base gasket on the left side of the cylinders.