Pushing Oil-Probable Cause

[Christen]

New member here looking for some advice.
I bought a new 1971 XS1 650 back in college and road for 5 years so it's been a while. I recently bought a I 1975 XS 650B that I have been restoring. It has been sitting for approximately 20 years with old engine and fork oil, brake fluid and gas. The fellow I bought it from advertised it as is, ran well when parked, not running now, confirmed the engine wasn't seized and that the compression seemed good, it was his father's bike with 10k miles and very clean. I shipped it east and started work on it in mid August.I emptied all fluids, replaced fork seals and oil, replaced master cylinder, flex lines and caliper piston seals, emulsified all rust in the tank and coated with POR 15 tank liner, rebuilt both carbs, new filters, rebuilt petcocks, lubed all cables, sprayed some lube in the cylinders, cranked by hand the 50 x, installed a new battery, gapped and installed new plugs, checked spark (good) and refilled oil and gas. five kicks, it started and idled evenly around 700 rpm for about 4-5 minutes (until the engine heated up). then started misfiring and oil smoking out the tail pipes and a bit of oil smoke off the front face of the cylinders.

Turned the bike off, pulled the plugs and saw they were fouled with oil.

Other than the oil leaking into the cylinders, the engine was running very nicely. My guess is the head gasket is leaking and I should have re-torqued the head bolts before starting. It could also be worn valve guides and/or valve seals. In any case, I have to pull the engine and get into the head and will check valve fit and top end condition but I would welcome any advice on how far to go since I will have the engine out. Focus on the oil leak and any observable wear or do a total engine rebuild)?

Thanks for your thoughts.
Christen

 

[lakeview]

A head retorque might fix it without anything else - check the tech section about waking up a dormant bike.

 

[gggGary]

A head retorque might fix it without anything else - check the tech section about waking up a dormant bike.

Certainly worth a try, it's simple to do and will cause no harm. Did one last night on "Milwaukee Iron" I usually do them now before I attempt a start... Takes me about an hour start to finish including polishing the stud nuts, but I've done it once or twice... Insert pointless picture of engine here.

Can also be a cracked valve seal. After the retorque get it outside, warm it up good and see if you can ride it up and down the block a couple times, see what happens. Give it a day or two after a retorque to stop leaking......

 

[gggGary]

Welcome to the forum! At 10K miles a top job should be far enough, I wouldn't expect to need to open the cases. Jim has an excellent how to. I'll let him show up and point you to it. Jim-bob you 'round?

 

[Christen]

If a head torque would fix it, that would be very nice, I must say. One step at a time. Lakeview and gggGary, thanks for your suggestions and quick response. I'll let you know how it goes.

 

[Jim]

Welcome to the forum Christen! Like Gary and Lakeview said, try and put some miles on it after a re-torque and see what happens. Ya never know....
As long as it shifts through all 5 gears, there shouldn't be any need to open up the bottom end. The top end thread Gary mentioned is here.

 

[gggGary]

Sorry for the delay Christen, Jim's usually faster'n that........... Blame it on the ankles.
A great how to, several have already done their heads using that as a guide. That's a pun you'll catch onto in a bit.

 

[5twins]

It's not so much the mileage on these motors now, it's their age. The rubber stuff inside like the valve guide seals and the front cam chain guide are routinely failing because they're so old. Freshen the topend up and you should get many years of good service from the bike.

 

[Christen]

Welcome to the forum Christen! Like Gary and Lakeview said, try and put some miles on it after a re-torque and see what happens. Ya never know....
As long as it shifts through all 5 gears, there shouldn't be any need to open up the bottom end. The top end thread Gary mentioned is here.

Jim,
Thanks for confirming "re-torque and ride" as step one and the link to top end thread. Hope this works and I can get in a few break in miles for the bike and me before the snow flies.
This is a great forum. Much appreciated.

 

[Christen]

It's not so much the mileage on these motors now, it's their age. The rubber stuff inside like the valve guide seals and the front cam chain guide are routinely failing because they're so old. Freshen the topend up and you should get many years of good service from the bike.

Thanks 5 Twins. Hoping re-torque works for now. May do the top end over the winter.

 

[Christen]

Welcome to the forum Christen! Like Gary and Lakeview said, try and put some miles on it after a re-torque and see what happens. Ya never know....
As long as it shifts through all 5 gears, there shouldn't be any need to open up the bottom end. The top end thread Gary mentioned is here.

Jim,

I came across this top end thread when I was looking into the scope of a rebuild. It's a very nice and detailed piece of work. Great to have this reference.

 

[Christen]

The head bolts haven't been turned in 20+ years. I'm thinking that I should loosen them 1/2 turn and then torque to spec. If there is any resistance from oxidation or gunk binding the nut/washer/head surface, the wrench may click before the nut budges. Does anyone agree this might be a concern?
Thanks.

 

[gggGary]

Remove nuts one at a time, 1/2 turn is NOT enough, polish use anti seize, install, and torque to 30 ft lbs, M/L.
Read through the BIG retorque thread. catch the two 12mm head bolts under sparkplugs, and the 6mm way in the back above the cam chain tensioner. CAREFUL on that one!

 

[MaxPete]

The head bolts haven't been turned in 20+ years. I'm thinking that I should loosen them 1/2 turn and then torque to spec. If there is any resistance from oxidation or gunk binding the nut/washer/head surface, the wrench may click before the nut budges. Does anyone agree this might be a concern?
Thanks.

Yes - you will need to remove the nuts and clean the threads and the area under the nuts to ensure a valid torque value.

Now, many folks re-torque the head several times following a re-build and in my opinion, after you've had the head off and cleaned everything up, re-torqueing the heads over the next few weeks as you break-in the bike will not require removal of the nuts for cleaning.

The key thing is clean threads and clean surfaces under the nuts - so that your torque wrench is reading the torque to tighten the fastener and not the torque to overcome friction.

The thread has good info on all of that - and welcome!

Pete

 

[Christen]

Remove nuts one at a time, 1/2 turn is NOT enough, polish use anti seize, install, and torque to 30 ft lbs, M/L.
Read through the BIG retorque thread. catch the two 12mm head bolts under sparkplugs, and the 6mm way in the back above the cam chain tensioner. CAREFUL on that one!

Will do and thanks for heads up on 12mm and 6mm bolts. Appreciated.

 

[Christen]

Yes - you will need to remove the nuts and clean the threads and the area under the nuts to ensure a valid torque value.

Now, many folks re-torque the head several times following a re-build and in my opinion, after you've had the head off and cleaned everything up, re-torqueing the heads over the next few weeks as you break-in the bike will not require removal of the nuts for cleaning.

The key thing is clean threads and clean surfaces under the nuts - so that your torque wrench is reading the torque to tighten the fastener and not the torque to overcome friction.

The thread has good info on all of that - and welcome!

Pete

Thanks Pete,
Lots of folks with experience and good advice on this site. I should have checked here BEFORE I started the bike up last weekend.

 

[gggGary]

To clarify a point; the reason 1/2 turn isn't enough is that the studs are long and have some spring. You can either tighten or loosen 1/2 turn and all you did was twist the stud a bit. It's only after you hear the big tink of the nut breaking loose from the stud thread that any meaningful loosening or tightening is done. You'll know what I mean once you actually crack the first nut loose.

 

[Christen]

gggGary,
I see (hear) what you mean. discerning what's a stud "tink" and torque wrench "click" takes concentration. I undid the head nuts in reverse order, cleaned studs and nuts and re-torqued, started and ran the bike for about 15 minutes, good steady idle and no white smoke out of the mufflers. The re-torque seems to have solved that problem. I am now getting carbon deposits on the right plug (rich mixture ?) and engine stall when revving above 2000 rpm. I re-set the mixture screws on both carb's (both now one full turn out ).The advance mechanism looks like it's working and points are gapped and spark is here. I believe the plug caps, leads and coils are original '75 so I'm going there first thinking this willl be an improvement in any case. Snow is forecast this week so My first ride may have to wait until spring anyway. Thanks to all for the head bolt torque advice. saved me a lot of work and headache.

 

[YamadudeXS650C]

I believe the plug caps, leads and coils are original '75 so I'm going there first thinking this willl be an improvement in any case.

Yes, there's a good likelihood that you have degradation in these items, and they are not expensive to replace.

I'm anticipating that we here in the Syracuse area (not sure what part of NY you are in) will have a couple low-50's days left to take a short spin.

 

[Marlin72xs]

gggGary,
I see (hear) what you mean. discerning what's a stud "tink" and torque wrench "click" takes concentration. I undid the head nuts in reverse order, cleaned studs and nuts and re-torqued, started and ran the bike for about 15 minutes, good steady idle and no white smoke out of the mufflers. The re-torque seems to have solved that problem. I am now getting carbon deposits on the right plug (rich mixture ?) and engine stall when revving above 2000 rpm. I re-set the mixture screws on both carb's (both now one full turn out ).The advance mechanism looks like it's working and points are gapped and spark is here. I believe the plug caps, leads and coils are original '75 so I'm going there first thinking this willl be an improvement in any case. Snow is forecast this week so My first ride may have to wait until spring anyway. Thanks to all for the head bolt torque advice. saved me a lot of work and headache.

Hi Christen. Before buying all that stuff, try removing the spark plug wires from the caps and coils. Then cut off a 1/2" on both ends, then reconnect. It worked for me. I do that on my new wires, too. Can't hurt, no cost! Good luck.