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Oil leak?

5K views 32 replies 8 participants last post by  Spockster 
#1 ·
Ahhh but yet ANOTHER problem with the old 750. So I have literally put no run time on the bike yet because I have been to busy working on it.

Well here is the deal, today I thought I’d go get the bike inspected and get it legal for the first time in 4 years.... well anyhow the rear exhaust manifold is covered in oil, the rubber motor mount above the manifold has oil on it as well. Where the exhaust hooks into the manifold smokes quite a bit when motor gets warmed up.... thtiming chain tentioner has oil on it as well and oil running down the motor above the tentioner. My guess is the weep hole, or half the problem anyways.

So what I’m wanting to know is could the weep hole cause oil to be all over the manifold? I wouldn’t think so seeing how it’s kinda below the manifold.... bike does smoke a little when warmed up, nothing major at all..... I was thinking maybe the bike had to much blow by causing oil to get into the manifold, but seeing how it’s on the outside of manifold as well and the motor mount... could the weep hole actually be the problem? I can’t get it inspected with smoke rcoming off the exhaust the way it is lol
 
#3 ·
I thought the same thing, but valve cover seems to be fine. I ran my finger all around it. No oil on it... Only leak I can find wth a quick look was that weep hole... but bound to be another somewhere else. Surely if rings was bad enough to let that much oil out the ol bike would smoke like a train.
 
#6 ·
If the plug well is holding oil, the spark plug starts getting coated as soon as you break it loose.

Looks more like carbon on the piston, and not too severe. Yes, both plugs should show it if it's pumping oil.

Everybody should have a snake cam! :cool:
 
#7 ·
Here’s a couple pics of what I’m talking about, maybe it will help a bit.

First pic On the exhaust where it hooks to the manifold, that chrome collar that I set my spark plug wire on is where it smokes from and that little mount/bushing above it gets oil bubbles off it.

I took my phone and put it under the manifold and snapped a picture to show how everything’s wet. Valve cover not showing any signs of leaking... I know for sure the weep hole is leaking oil...

It for sure has me puzzled on how oil has gotten everywhere like this 🤔 going to see if my local part store has the correct o rings for the spark plug well in the morning.
 

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#8 ·
Isn't there an o-ring in the deep-well spark plug holes or something? I've heard of other users needing to replace that then it starts to leak and fill the plug well.

The plug well screws out of the case using a large hex (people report using the axle nut to remove it) then the o-ring is replaceable from what I remember reading about it.
 
#9 ·
Yes you are correct, main thing I’m trying to figure out atm is why my manifold is covered in oil. I could see a leaky valve cover gasket causing the problem but it’s not leaking.

The weep hole is on opposite side of motor below the manifold so I can’t see that being the problem either. It’s not a old leak because I have fresh oil dripping down from somewhere.

Unless the weep hole is just blowing oil everywhere, but I’ve only heard of them being small leaks running straight down the motor.
 
#10 · (Edited)
Not trying to offend, but ... Are we sure it's coolant? Did you taste test it? :)

The rear weep hole is much lower then the manifold, almost at the base of the cylinder.

Rear coolant pipe is ahead of, and higher, than the manifold.

 
#11 ·
Not trying to offend, but ... Are we sure it's coolant? Did you taste test it? /forum/images/smilies/smile.gif

The rear weep hole is much lower then the manifold, almost at the base of the cylinder.

Rear coolant pipe is ahead of, and higher, than the manifold.

It’s most definitely oil, even smells like oil when burning off the exhaust. It’s not a coolant leak.
 
#12 ·
Take some spray brake cleaner and completely clean the oil off the entire area. It may take a lot of it, get the Walmart Supertech brand. Once clean and dry, get some Arrid Extra Dry spray, and spray the whole area with it. It is bright white, and any oil leak will instantly become visible. Start the engine and wait. You can also get dye to put in the oil that shows up under a blacklight. I seriously doubt it is coolant, that is quite different from oil. However, there is a coolant elbow fitting on the left side of the rear head that tends to leak. It has an O ring on it, but even with a new O ring, it can leak if you wiggle it around. And yes, I have done the taste test on coolant. Obviously ethylene glycol is poison, and you don't want to swallow any. I just touch it with my finger and touch my tongue to it. If it is coolant you will immediately get that sweet taste. Spit it out. It will never be anywhere near your throat.

You might also want to remove the gas tank and run the engine on a temporary gas supply. You can get a much better look at the top on the engine with the tank off.
 
#13 ·
Awesome advice I didint think much about trying something like that. I appreciate the help! I’m going to give it a shot. I know that little hole next to tensioner leaks oil for sure. Hopefully I can have it fixed tomorrow.

And by chance does anyone know what size the axel nut is on these bikes?
I’d like to know the correct size so I can find another one and just make a homemade tool, that’s way I don’t have to keep taking the rear axel but off when I need to remove the spark plug wells
 
#16 ·
Someone gave me a battery powered black light for Christmas. Antifreeze will glow under a black light, but you need dye for the oil. Small bottle of dye is $5-8. Peanut butter glows green! So does ketchup.

The light couldn't be real expensive, but it has a laser, LED flashlight, LED floodlight, and LED black light.
 
#19 ·
One more question for you guys, when I got to change these o’rings on the spark plug tubes- before pulling the tubes out is the valve covers suppose to be removed first? If so what’s the purpose in that? I’m just curious I read somewhere else that the valve covers needed to be removed in order to pull the spark plug tubes out
 
#21 ·
When I got my 750 my rear cylinder spark well leaked badly as did the rear ACCT. New well gasket cured that as did the new gaskets on the MCCT. But I was amazed at where the dripping oil and vapor went all over the bike.
 
#22 ·
I had gas leak into the oil while I had be bike in storage last winter. The first time I had it on the highway and really opened up the bike the added pressure found ways to get that oil out. Being new to motorcycles I brought it to a mechanic. He drained it and put in fresh oil. It doesn’t leak anymore but the point is when it did leak it was everywhere. I spent a full afternoon cleaning it off
 
#25 ·
I could probably find one to buy on amazon or eBay. May order a few of them. I tried my local part store they don’t have anything....

However I do have a small machine shop located in my town, I’d imagine he probably has what I’m looking for.

Everything else is located an hour away from me each direction.... that’s what happens when you live in a small town in middle of know where I suppose. Haha
 
#26 ·
I'm not understanding about the "weep hole" Do you mean the water drain holes in the spark plug wells? Oil cannot get into the spark plug wells unless the O rings are leaking. There are rubber seals around the bolts on top of the engine that hold the valve covers on. It could leak oil from around there and not leak around the gasket between the valve cover and the head. The spark plug wells can be removed without removing anything else but the plugs. I don't have the manual handy, but they have a hex on the outer end that something like the head of a certain size bolt fits into. I don't remember what size.
 
#28 ·
Finally found something to take the plug tubes out with. Will buy the o rings tomorrow. Even ordered a manual for the bike few moments ago so I don’t have to constantly asking questions bothering anyone more than I have to lol

I had some old parts laying around from a plumbing job I had done, I used a end of a valve to remove the plug tubes it worked perfectly. I uploaded the pic... it’s not stupid if it works right?
 

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#30 ·
I did not know this, but I guess it’s always good to have a book anyhow it was used but it was only 15$ In readable condition so I couldn’t pass it up... and on a side note... I have no clue how to check any of that stuff, I’m pretty new to this still all I have figured out how to do is post things! Haha.
 
#33 ·
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