crankshaft oil seal

I installed a cNw e-start last summer, which came with a new crankshaft oil seal. I was surprised (dismayed) that the old one literally fell out of the case in my hand with no prying required. I put the new one in with some Yamabond goop around it. No leaks for the 300 miles I got to ride last season.

However...

The bike's been on a lift in my shop since November for winter maintenance and yesterday I found a puddle of oil under it. It's dripping from the vent slots in the cNw chaincase. Obviously, wet sumping has filled the crankcases to a level where oil can find a way out. Suspects would be the chaincase bolts (with blue Loctite) or the oil seal. I haven't been in there yet, but I suspect the seal.

So...

Is there a preferred seal to use, and a proven way to seal it to the case? Disassembly will not be fun and I don't want to do this again.

edit: Maybe a more pertinent question, is it possible for oil to wetsump that high, or should I expect the lower chaincase bolt instead?

How much oil makes its way into the primary is contingent on several variables, though I would think that even a weak drive side crank seal would still offer some resistance to migration, perhaps combined with migration through the fixing bolts could get the level that high given enough time. You say you were able to put some miles on without any apparent problems with the seal? You'll have to go in and check regardless. When you're in there check the endplay on the crank, there's not much space between the lip of the seal and the keyway, if there's too much float the seal will leak no matter what. A speedi-sleeve can be installed in-situ if the problem is determined to be with the seal bearing surface on the crank

I had exactly the same situation with my 850 Mk2. cNw electric kit, new crank seal, yada yada. Installed a anti-sump valve in the oil line. Oil leaked from the primary cover vent slot. I went in and found that both the new crank seal and the inner cover lower mounting bolt showed signs of leaking. Installed another new crank seal and sealed the inner primary bolt threads with gasket sealing goop along with new tab washers. Well, the SOB leaked again!
I went in again and found the oil seal bone dry but found oil leakage at each of the 3 inner primary mounting bolts. The gasket sealing goop on the threads was hard and cracking. The lowest bolt was actually loose I could unscrew it by hand despite the tab washer. So, I sealed the bolt threads again with
Permatex 57535 Seal & Lock compound. While I was in there I replaced the transmission shaft oil seal. I also removed the RGM anti-sump valve from the oil line and replaced it with a manual valve which has an ignition interlock device included that I bought on eBay. That proved to be a cheap unit as the wires were undersized to serve the TriSpark ignition and the dual coil. I had trouble starting. So I bi-passed the interlock, easy starting resumed and now I have the dangerous manual valve with no fail-safe device. I plan to fix that ASAP with this valve from Feked. I have gotten pretty efficient at disassembly and reassembly of the entire primary with cNw electric start.

Well, I had intended to get into the primary anyway as I was getting a very slight knock at idle that I believe to be the clutch contacting the inner chaincase. This leak has shown up while the bike has been laid up for a few months, no doubt from wet sumping, but I have no intentions of addressing that with a valve. I'd sooner drain the oil before putting the bike up for the winter.

Thanks for the tip about Permatex 57535. I'll get inside and see what the root cause is next weekend.

lazyeye6 said:

I have gotten pretty efficient at disassembly and reassembly of the entire primary with cNw electric start.

Click to expand...

Any tips on doing that? I was gonna ask Matt, but since you're here...

1. Loosen rear wheel nuts; adjust adjusters and push rear wheel forward to loosen up drive chain
2. Loosen top and bottom mounting nuts, and adjuster nuts and push transmission forward
3. Remove Primary cover
4. Remove clutch plates
5. Disassemble electric start parts in reverse order of assembly
6. Use pneumatic roto hammer to remove rotor and clutch nuts. Remove rotor. Let the stator hang.
7. Remove circlip at the center of the drive sprocket holding sprag gears in place.
7. Use small 2 arm gear puller put pressure on the sprag gear while turning it slowly right. Might have to reposition the puller a couple of times.
As the gear starts backing out it will suddenly pop lose
8. The remaining front sprocket has two threaded holes in it. Buy 2 grade 8 5/16-24 bolts and along with a puller screw them fully into the holes.
Tighten puller until you are afraid of stripping the threads (yikes!). Tap on the side of the sprocket with a small hammer in a few places and increase
pressure the with puller. Eventually the sprocket will break loose from the crank taper.
8. Pull engine sprocket/chainwheel and belt off together.
9. Remove the inner primary bolts and lift it free.
10. Reassemble as per Matts directions except first reinstall the sprag gear into the sprocket by placing it over the center of the sprocket while
slowly rotating the gear to the right and firmly pushing it in. A large socket and a rubber mallet might help. It will pop in. Drive it in until
the groove for the circlip is fully exposed. Re-install the circlip. Test it. The gear should lock turning it counter clockwise and spin freely
when turning it clockwise. Pay close attention to directions for measuring for and installing spacers between inner primary and the boss
where the outer cover mounting stud screws in.
11. On reassembly adjust and set belt tension and lock the transmission in place with it's mounting bolts. Better lose than tight!! Then adjust
drive chain and tighten rear wheel axle and nuts

PM me if you run into snags.

Update -

Yup, crank seal leak. Dunno what I'll do different. I guess JB Weld on the outside.

lazyeye6 said:

8. The remaining front sprocket has two threaded holes in it. Buy 2 grade 8 5/16-24 bolts and along with a puller screw them fully into the holes.
Tighten puller until you are afraid of stripping the threads (yikes!). Tap on the side of the sprocket with a small hammer in a few places and increase
pressure the with puller. Eventually the sprocket will break loose from the crank taper.

Click to expand...

I was disappointed that the spacing of those holes is different than the stock sprocket and my sprocket removal tool wouldn't fit. The 5/16-24 bolts in my steering wheel puller kit are about 1/2" too short to be able to get the puller in place. Ain't gonna find fine thread grade 8 bolts 5" long at Home Depot (I looked). Got some on order from McMaster.

Fortunately, I had used anti-seize on the sprocket and was easily able to remove it just by screwing in the bolts against the primary case..

I found those bolts both at the corner Ace Hardware and Tractor Supply

following this thread. interesting comments on the seal and mounting bolts as i'm considering an e-start. no experience here, so I can't contribute much. as for using JB weld on the outer surface of the seal, IMO, bad idea. JB is some serious tough stuff. it will glue that sucker in place, and most likely seal ad stop the leak, but if and when you go to remove it, you WILL have issues - guaranteed! non-related curious - when installing the inner primary case, does cNw recommend using a gasket or sealant (or both) between the crankcase and the inner primary? I know alton specifies only sealant.

gasket

Just be sure the leak is actually coming from the OD rather than the ID of the seal (looks like you already used sillycone around the OD), you'll drive yourself nuts replacing seals otherwise. IMHO, after chasing down this leak, the culprit is often the bearing surface on the crank (wallowed out), or excessive float allowing the seal to overlap the key slot. The former can be fixed in situ using a speedi sleeve (installed backwards). The SKF version of the speedi sleeve actually overlaps the key slot very slightly, so may remediate the latter scenario as well.

Not sure which puller you're using, but there are generic steering pullers available at auto stores that provide enough range to accommodate most needs

The leak is definitely around the outer ring of the seal, from the crankcase. JB Weld may indeed be an extreme measure, but it can be removed with a wire wheel. I had used Yamabond on it when it was assembled.

A gasket is included in the cNw kit, Joe.

My universal puller is similar to that, acadian, and the screws are 4" long.. not quite long enough to get the "foot" between the cross bar and the end of the crankshaft.

Going down to the shop in a few for some more diagnosis. I hope I have another seal handy.

Im on seal four because the first three leaked. This time I put in a speedi sleeve not because the crank looked compromised but because I would gain a few thou of thickness. At this point Im getting tired of the leak. It is not leaking on the OD of that Im sure. As for sumping, mine has a new pump and a new engine and it still sumps. Ill just drain it if it sits more than a few weeks.
Havent run the bike since I put it in because other bits are caught out at the machine shop due to the Great Panic.
Ill let you know how it goes and will await with baited breath your reports on your bikes.

Bought a bag full of these rubberized seals back when I had the same issue. With the new build I used a speedi sleeve, plus shimmed the crank float and installed studs in the case to replace the through bolts. Perhaps a result of all three measures combined, but my primary's been dry as a bone ever since (knock on wood)

As for JB Weld, it can be easily softened with a bit of heat from propane to where it will release the crank seal without a fight.
What is a speedi sleeve and how does it help in these situations?

It's a repair sleeve that restores grooved and marred shafts back to new, made by SKF.

Tornado said:

What is a speedi sleeve and how does it help in these situations?

Click to expand...

They come in all sizes and are (were) routinely used on the nose of an automobile engine where the timing cover seal runs.

Could anyone who has used a speedi sleeve on a Mk3 please let me (us?) know the correct size required?

I have engine oil finding its way into the primary despite several crank oil seal repolacements.

So, given the fact that these seals can leak twixt seal and crank AND seal and case, what is the best seal to use ?