Transmisión oil leak

[Mongrel505558]

If you're not in a hurry to take your transmission apart, I'd live with the leak until then. You said it isn't a really serious leak. The amount of oil in the transmission isn't an exact science. With the leaning bike on it's jiffy stand the level will "correct itself". Take a look in the kicker cover filler hole and try to see what level that corresponds to. Just check the oil level often. It is a very common problem that stems from factors like wear on the spacer that spins (hopefully - that's what the "L" key is for) in the seal, the cork gasket behind the seal, too much clearance (from wear) between the main drive gear bronze bushing and the main shaft, etc. Of course if the oil is gumming up your clutch you may want to get into the transmission sooner than later. Then you can replace the main drive gear seal and cork gasket, spacer, install Saddlebagrail's seal if you want, and possibly replace the main drive gear bushing if it's shot. Supernuts hardly fit on anything I've encountered, and I don't think they're as effective as they claim to be.

[RooDog]

If oil is getting into the clutch it is most likely coming through the center of the main shaft. Nothing at all to do with the main drive gear. The MoCo only used a piece of cork within the center nut, but one can install a 1965 seal, #12014, or even two of 'em, there's room, and this should keep the clutch dry.....
....RooDog....

[Panacea]

You don't have to take the tranny apart to use the spacer with the "O" ring, you will need to remove the seal, the cork, then swap out the spacer with the modified spacer from saddlebag ray. The new spacer has an o ring that sits on the mainshaft just inside of the splines, where it should be smooth.

[DaCs]

I decided to remove the old seal and use the spacer 17-0392 with the o ring, the problem is that it fits very tight, I would have to tap to make it fit and the notches make the o ring break, has anyone used this before?

[socalrider]

It took me about 3 destroyed orings before i got it right. I think i used electrical tape on the outside of the gear so the oring can slide on.also applied lots of vasoline over taped part. Good luck

[Lowbikemike]

I use STP when assembling things like that, super slick and always aids in installation. The next issue you will encounter is the spacer cut out damaging the outer lip of the seal that is installed next. Ray (spacer maker) told me now to worry about the outer seal, it just keeps dust out anyway.....really didn't like that answer.

[DaCs]

I use STP when assembling things like that, super slick and always aids in installation. The next issue you will encounter is the spacer cut out damaging the outer lip of the seal that is installed next. Ray (spacer maker) told me now to worry about the outer seal, it just keeps dust out anyway.....really didn't like that answer.

Im using v-twin, loking oem a vtwin, looks identical proportions, any idea why it damage seal?

[Lowbikemike]

As socal mentioned, its hard to put on and not tear the o-ring. I'd take his advice on taping the shaft and use plenty of lube.

[George Greer]

I decided to remove the old seal and use the spacer 17-0392 with the o ring, the problem is that it fits very tight, I would have to tap to make it fit and the notches make the o ring break, has anyone used this before?

I used one of Ray’s spacers, and when I installed it, the o-ring tore exactly as you described.

I took a riffles (jewelers file) an chamfered the spline edges of the shaft. Wrap the threads with some black electrical tape, or Teflon tape.

Vasoline as a lubricant and then it went on smoothly

George

[nifty]

Check that seal lip area of spacer is concentric with ID of spacer (many are not, even some genuine ones)
If spacer is tight on sleeve splines, deburr or polish either or both as required so its a slide fit.
When changing seal, select 4th gear, this stops sleeve gear moving inwards as you install everything, but don't beat on sleeve or you will bend selector fork etc. Use a tool to install seal square to shaft, best is set up that uses clutch nut to gently push both seal & pre-fitted spacer into case, as one.
Use heavy duty James seal. With James seal and or modern sealants the cork ring is superfluous.

I have also successfully used a metric o-ring in early gearboxes with all stock parts.

Alternative 36up high gear o-ring modification: 36mm x 1mm o-ring fits into many existing undercuts on early stock oem high gears (at step adjacent to roller ends), tape splines, lube & stretch o-ring into place. Remove tape. Use corresponding oem early notched seal collar/spacer, many of these spacers have existing inner ID chamfer, or polish new lead-in chamfer at inner ID, end result is spacer slightly compresses & rides over o-ring, just before spacer abuts against step adjacent to roller ends, spacer snugs up nice & seals to high gear with no machining or spline goo required.
However, variations in sleeve undercuts may cause problems. Ensure spacer rides up over slightly compressed o-ring without cutting o-ring. (this is when having trans in 4th gear helps locate high gear) Re-lube, install spacer into new seal, install seal as above.

When you eventually have trans apart, use fine compound & lap the inner end face of spacer to step of high gear, when you have perfect ring contact here you don't need any sealant, or o-ring (so long as sprocket nut stays tight). Re-check/adjust high gear end float after lapping.

The early L key seems to assume the sprocket nut will be loose, so key required to prevent spacer & sleeve wear.
Proper functioning of trans & seal requires that sprocket nut remains tight and clamps spacer by its ends.
L key and its slotted spacer were later deleted, groove/undercut in sleeve deepened for factory o-ring to seal against ID of new spacer (sans slot for L key, but .030" narrower than early spacer)

Contrary to some OEM manuals, 80ftlb is plenty for trans sprocket nut. Most "Supa-Nuts" will handle 80lbs ok.
When you can fit them, I like supa nuts.

Re oil fill: All factory literature says 1.5 pints, which on a 4 speed with bike upright equates to absolutely full to brim of pig snout and funnily enough right at level plug of late kicker cover. this oil level is not much below clutch pushrod. Sure its a lot of careful work to get a 4 speed to keep this oil level when on side stand and when riding, but anything less and you are hurting your trans.

Nifty

[Panacea]

I found when I look down into the filler hole with a penlight, with the bike on the side stand, the oil is well below the fill hole opening, down near the bottom. This keeps the oil below the point where it will try to seep past the main drive gear bushing. especially on a tranny with a well worn bushing. Just my personal experience, every body has their own...

[nifty]

Panacea,
What you say is correct, but my preference is to give trans best chance at long term survival.

Nifty

[DaCs]

It is exactly what I did, put electric tape, file the sharp corners a bit with a jeweler's file and just press with small strokes, a lot of grease and it enter without problem. I appreciate your help friends! and I hope this thread will serve future members

[saddlebagrail]

Sorry guys I haven't been here in years ,I just got a notification ,if anyone need to contact me here is my email cheaper buying direct than from my eBay due to fees...and yes this is the solution to a leaking 4 speed,unless the main drive gear bushing is worn out and even if you change the small seal at the end of main drive gear it will still leak after a short while,Ray

saddlebagrail@yahoo.ca

[doc9339]

I've stated this a few times on posts with the same subject, and it should be taken into consideration...... One part NO ONE LIKES to check, because it takes dissassemby of the tranny, is the diameter of the mainshaft: Yes, it gets worn. If its worn, you can change every single related gasket that could cause a leak, and you will still get one.

How do I know? I had the same leaky mainshaft probs most have, on more than one 4 speed. On one I changed out every single related gasket that could cause a leak, and it would still do so. I only found out my point when I finally took the tranny apart because frankly, my tranny was probably 10 owners old, and since it was winter, I wanted to rebuild it. The tranny seemed to run OK, but that leak was killing me

I mic'd the mainshaft, and yes, it was worn, allowing a very slight wobble when under power. When this happens, gasket changes will not work, period. I canned the old mainshaft, got a new one, and yep, afterwards, it stopped. This goes for all your gears as well. If the shafts are worn, or the bushings in the gears are worn, it will transfer slop and cause undue wear on the mainshaft

I hightly recommend anyone with a continuing leak at the mainshaft area to grin and bear it, and tear down your tranny. Dont take shortcuts, and check every single part for wear. Remember, these trannys are decades old, and who knows what kinda work was done thru the years. Ill bet 90% of our trannies out there need parts replaced, even though it seems to perform OK.

I also recoommned to anyone with any sort of mechanical ability to rebuild your own if needed: It isnt that hard, takes a minimal amount of hand and measuring tools, (like a $25.00 elctronic measuring caliper), and the Factory Manual covers the rebuild in detail. The parts aren't that expensive, and with crazy shop rates nowadays, you can not only stop the leak, but save some money