My turn to ask for help.

So....My oil leak has returned.
Background:'82 XJ 750 Seca that I refurbished 8 years ago (oil cooler has been fitted), and which developed a leaky base gasket 2 years ago.
I redid the gaskets on the top end again once the leak became bothersome (including the valve cover doughnuts).
The leak is not present at in-town speeds, but is very evident at highway/freeway speeds.

My thoughts are a blocked breather, or that the valve cover is still not sealing properly.
I do not see evidence of oil leaking from the base gasket, or the cam feeds. It's running along the head gasket line, but the head gasket is new as of 2 years ago (the bike has mostly sat since), and the head nuts are at the specified torque.

More background: The cases are from a Maxim, and the studs are what came with the cases. It may be that they are beyond their stretch limit, but I"m not convinced of that at this time (could be wrong though).

She runs strong with no smoke.
Suggestions are welcome. I'd prefer to not limit my leak-free riding to in-town.

 

Had a problem with a 750 maxim a customer dropped off.
Small crack in cam chain tunnel at front of cylinders just where it meets the main cylinder area at the head gasket. PO had over torqued the 6mm nut at the front to stop a leak.

 

If you clean the oil and put the bike on the side stand and start the engine as oil cannot run uphill is may be easier to locate the source of the leak. Then again if it is only happening at highway speeds that won't work.

 

Yep. That's the problem. By the time I can see the leak the oil is all over the front of the head.

Hmm.....maybe. I don't recall overtorquing that nut though. And the leak is above that area. Worth looking into though. Thanks.

 

Perhaps tightening the cam cover bolt nuts slightly will stop it?

 

They are already torqued to spec. Tightening them more will only result in damage.
I'll be taking the breather apart as soon as weather and time permit (Likely Wednesday).
It may be that the mating surface for the valve cover gasket is nicked somewhere that I missed.
One thing at a time.
The only big change I made prior to the original leak (which was solved) was to fit the correct oil cooler instead of the one from a 650 that I had been running for several years. I did pressure test the cooler before fitting it and found no leaks. I do wish that I had eyes to see the front of the engine while running on the freeway.

 

Yes you don't want them damaged. It will be something simple, when was the last time you checked the breather? I did the breather on my engine but that was because I was rebuilding it.

 

I checked it last when I swapped the cases, so about 5 years ago.

I do wonder about the possability of a crack in the head. If the breather ends up being a dead-end I'll invest in some flouescent dye.
She was leak-free for a long time. This is so annoying.

 

Hopefully it is the breather.

 

It would be very nice if it was. I'd hate to have to to pull the head again to have it resurfaced.
She's been a very reliable machine sine I did the recomissioning, and suits me perfectly.

 

You can try to spread talcum powder around base run engine you might see where the leak is .

 

Will do. I haven't had many rides out of the city since getting her back home. I am certian the the leak is not at the base gasket.

 

Yes as you say check the easy things first. I know CB750's SOHC engines can have head gasket problems, I had an oil leak from mine and replaced the gasket. I have not had that problem with my XJ. Hope the head is not cracked.

 

The other way to find leaks is with spray deodorant after cleaning the engine and when it’s dry and cold spray liberally and fire her up and use a fan to keep thinks cool and the deodorant will go black the second oil appears.. it could be an o ring around one of the cylinder head locating dowels.

 

I first suspect the valve cover gasket

 

I am leaning in that direction. There would be more oil splash off of the cams at higher RPMs. I won't be able to do any checking until Friday. Rain is foreacst for all day tomorrow.

 

If the gasket checks out okay and the breather system is clear you may want to to check for too high of crankcase pressure, CLT test for worn engine rings causing too much pressure entering the crankcase, hopefully this isn't the issue and would be the worst case outcome.

 

Will do.
That is unlikely as I measured the rings and bores when I did the refurb, and again when I changed the base gasket. They were still well in-spec, but that doesn't preclude the possability of a failure.

 

I finally managed to get other projects out of the way and started to look into things further.
The breather is clear.
I pulled the valve cover and found..........nothing out of the norm.
There may be a spot near the front right where the cover is slightly warped since I found oil under the gasket there as soon a I lifted it up.
I didn't take the gasket off to check since it's glued to the cover and I don't have a spare on hand (at least I can't find the box it's in if I do have one).
I cleaned it all up with alcohol and put a light coat of fresh oil on the head mating surface, followed by an extremely thin coat of RTV all around (not my first choice, but it will do for now). She'll sit overnight and I'll go for a ride tomorrow. IF the leak is gone then I know what needs to be done at the next valve clearance check. A glass plate and some grit to level out the valve cover (if it's not warped too badly).

 

I would not had put oil on the mating head. If the valve cover is leaking, you’re ALREADY GETTING oil on the mating surface. You’re trying to STOP getting oil on the mating surfaces. I would pull it back off, go over the gasket surface and the metal face and clean it with brake cleaner or some other agent that will quickly degrease and dry. Then put a narrow bead of rtv around the whole mating face. Also use a very fine machinist file and just lightly kiss the corners by the ‘half moon’s to eliminate any sharp burrs right on the corners here the faces drop into the curves.

I suspect the gasket has gotten some micro cracks in it, or the corners by the ‘half moons’ have cut into the gasket and you’re getting leaks there. That is an all-too-common issue right there,

 

you could try getting some 6mm "penny" washers , and cut a slot through them , and slide them under the cam cover bolt heads, then torque to speck,
that wont put extra pressure on the bolts , but will put slightly more pressure on the rubber gasket.
stu

 

Was going to suggest the same - go with the UV dye and try to track down the source. Might be the only way to approach this without tearing everything apart first.

Good luck!

 

Well I did that ride today.
Good news, it's not leaking any worse than before.
Bad news, it's still leaking.
Sigh.

I'll add washers next since it's hardly any effort. I know for certain that it's coming from the valve cover gasket since it's wet with oil, and oil isn't showing up anywhere below that. Darned annoying since that was leak-free for years before the base gasket leak showed up.

 

I kept on having a weird leak that sounds a bit like this with my last build (new valve cover gasket at the time also).
It ended up being the valve cover gasket and was caused by a slight chip in on the inside of the mating surface on the head.
I didn't wan't to but I ended up adding a bead of RTV inside the valve cover channel to make the gasket 'fatter' so to speak.
Put it on the bike without tightening right down overnight and tightened it the next day.
No leak now!
So kinda the same reasoning as the the washer concept.
Good luck!

 

Tomorrow will be the day to add washers and see if that finally fixes the oil problem.

Today got me thinking about an issue that I knew would come up at some point.
Urban riding has made it a more urgent issue for me than I'd prefer.

My hand hurts. And it's not the one that usually hurts.
Injuries are just part of life, and I've reached the point where holding in the clutch is more than a little painful. I can still manage, but it might not be for much longer.
I'd like to convert to a hydraulic system, but haven't found a bolt-on slave cylinder that I think would work on a 750 (there are plenty of options for 400cc and under).
I do know about the fitment of the pancake style slave cylinders to the clutch cover, but that requires more modification on an XJ than I'd prefer.

Suggestions are welcome. Preferably suggestions that do not require welding aluminum, and that use Yamaha parts (more for pride than function).

If it comes down to it I'll get a used clutch cover, turn a thicker center, and have it welded in so I can fit a pancake-type slave. Ideally it won't come to that.

@Minimutly. I seem to recall that you've played more with hydraulics than I have. Any recommendations from you would be most welcome.

 

To bad no one makes a recluse clutch for these bikes. I would be all over that.

 

Valvecovers can warp, put it on a plate of glass (etc.) to check. Yamaha actually has a spec in the FSM for how much warpage is acceptable.

 

Ya. The washers will be a temporary fix until I can get the shop set back up. Fortunately the new house came with a very nice surface plate (good enough anyway). A granite countertop that was removed during the last remodel.

 

You could lengthen the clutch actuating lever or fit one of these: https://www.ebay.com.au/itm/3037602...frny_iGlOIkpqT6uXtdcrpdbURtEcpIoaAqLCEALw_wcB

 

K-moe.......have you checked to see if your clutch cable is getting sticky?

 

It's not the cable. The pull is smooth and easy. Holding the clutch in at stoplights is the problem, especially after the third or fourth light.

 

I actually have one of those in a box. I never did manage to get it to fit on the bike, but I suppose I wasn't as motivated to make it work back then. I'll see if I can find the box it's in before I start yet another project.

 

Shift to neutral

 

Not in this city. I need to have a quick way to get out of the way of idiots.

 

it takes "X" amount of force to work the clutch, cable or hydraulic. to make the lever easier to pull it has to move farther. how far does a hydraulic clutch lever move?

 

Hydraulics multiply force beyond what can be achieved with just a lever (within the same packaging constraints).

I've driven vehicles that only had mechanical brakes, and there's good reason why hydraulic brakes were adopted as soon as they became practical.

I've also ridden motorcycles with hydraulic clutches, and have no trouble holding the lever in at a stop on those.

Turning wrenches paid the bills and then some, but sometimes the after effects suck.

 

The washers did the trick. I took a 20 min freeway run and all of the oil is still on the inside of the engine. Thanks.

 

Always... always keep your left foot on the ground.
so
+ 1

 

Hmm, I've no experience of modifying cable to hydraulic clutches (on bikes anyway). However, on cars you often have an over centre spring arrangement that takes some pressure off at full throw - might be worth looking at?

 

There is an idea. It'd be relatively inexpensive too.
If I don't find the Ezi Pull mentioned earlier I'll see about figuring that out, and as soon is it's made and fitted I'll find the Ezi Pull.

The only reason I thought about hydraulic is because Magura makes a bolt-on kit for just that, but it's a bit more expensive than I can stand. The knockoffs are all sized for 400cc and under.

 

Another reason for wanting a relatively cheap fix for this issue: the stiching on my Corbin seat finally gave up the ghost. Today's ride on the factory seat reminded me why I bought the Corbin. I can't have by backside hurt and my hands hurt at the same time, and I'm horrible at stiching leather. There are a few upholstery shops near me that do motorcycle seats, so my money needs to go to one of them first.

 

I sympathise. In my one hour spin on Saturday I had a numb bum from the xv750 single seat and aching wrists from the too straight flat(ish) bars. The bars are easy, I will get the propane torch on and add 5 degrees or so of in angle. The seat will need a gel pad and or new foam, might as well get it recovered with something better than black plastic - that will cost me...

 

Not a mechanical solution, but Voltaren works well for me with arthritis in my hands.

 

Thanks. I've been trying different things for years, and NSAID ointments do help. There are just some days where they don't help nearly enough.
I guess I should be thankful that the worst hand is on the throttle side and not the clutch side, or I'd have to fit an electric shifter ($$$).

 

Is CBD-oil an option?
THC free ofcourse.

 

It is, and hasn't helped. I won't go into the politics of what I'd prefer to use for pain management.
Most of the time my hands are around a 2, even just when resting (the right hand more often is a 4). Most riding puts them both at a 4, but the joy of riding is enough of a remedy that I keep on keeping on.
The day I started this thread asked about suggestions both hands were at a 6, and my left hand never used to get above a 4 during any normal activity. I'm used to dealing with the pain in the right hand (it's been over 20 years since the accident), but having both hurt that much at the same time was very concerning. I briefly thought about parking the bike and having my son bring the trailer to me.
The past two days of riding were great in terms of pain (aside from the stock seat, which is definately not all-day comfortable for me). I got out of the city as quickly as possible, and spent three hours each day enjoying the countryside.

I appreciate all of the suggestions and concern. This is a great community.

 

I'm not familiar with those numbers regarding the severity of pain or painlevels.
We've got thc-free or other to our disposal.
A big bummer for you but a big hooray for sticking to it.
Well.. it, riding bikes again, saved my sanity after not being able to ride for 3 years with muscle issues..

 

The last two pain scales mentioned in this blog are what my doctor uses, and what I refrenced.
https://lifewithmcc.com/2019/08/04/my-favorite-pain-scale/

 

how about something like this
https://www.progressiveautomations.com/products/mini-linear-actuator there's cheaper ones on amazon from china
didn't they have drag bike electric clutches that worked by moving the shifter? maybe they were pneumatic