[fergy]

Unless you were lucky enough to either buy the bike new, or buy it used from someone who kept every record of service, you don't know what shape your splines are in until you see them for yourself. And for you riders who have older bikes and are thinking you don't need to worry about this...Probably the most ignored and overlooked service item on a shaft drive bike is lubing the splines.

The Background: The VN750 is a great bike as we all know, but there is this "spline" issue that can be a real problem if it goes too long without lube. The problem is many bikes as they were being assembled were not properly lubed. The job was to lube the spline where it slides into the collar on the drive shaft, an area that gets lots of movement in and out as the rear suspension goes up and down, creating a ton of heat and potential wear of the teeth on the spline and collar. Well, apparently, someone was sleeping at the factory between about 2000 and 2006 as the largest sampling of our bikes that were discovered with dry splines were during those years. However, many older bikes have been found with the same dry splines, so it apparently had been missed here and there for the duration of the VN750 run. If the splines are left dry for very long, what you will find is not pretty. You'll find rusty nubs where the spline teeth are supposed to be as well as nubs inside the collar, and instead of a glob of grease when you pull them apart, you'll likely get a pile of red dust, which is the rusty, ground up bits of the teeth that are supposed to be there. If you are one of the "lucky ones", you will find some grease and perfect teeth. Either way, you can't let this go for too long, and checking and lubing them is really not that hard. Plus, once you have them lubed, you have almost zero chance of a failure back there as long as you re-lube them about every 10-12 thousand miles. If you are like me, you may find the teeth are already chewed off and you will need to find a replacement final drive and drive shaft collar. The collar you can order if you have to, for a decent price, but the final drive you will pay dearly for unless you can find one from a 750 that's being parted out. The final drive on my 02 is from an 86 model, so keep that in mind. They are all interchangeable from year to year. So, that's the story behind the spline lube problem... I don't really know for sure that it was a farm boy that did all this, but I'll betcha the real story would go something like that...



June, 2006: I'm going into this for the second time, this time replacing the final drive and the drive shaft coupling, but the procedure will be the same if you're only in there to check and lube your splines. You will see by the photos below, mine were shot and needed replacement, so I found a drive shaft with coupling, and a final drive on Ebay for around $100.

There are several excellent write ups on the 750 site and elsewhere, and I used them to go into mine the first time, but I really could have used photos of the steps to make me feel a little more comfortable. I'm certainly not taking anything away from those who posted writeups on this procedure, because they helped me tons, and now I'm hoping to give back by helping someone else. So this is for the guys and gals, like me, who need the photos!

I would suggest that before you start this procedure you order some replacement O-ring's KAW part # 92055-1044. This is the o-ring that seals in the moly and keeps it from gushing out and all over your final drive and back wheel. You could choose to remove your final drive, remove the o-ring and go to ACE hardware and see if you can match it up from the huge cabinet they have full of o-rings in the plumbing section. Either way, be prepared to replace it and keep a couple extras on hand.

Tools needed: Pliers, Metric Socket set (long sockets needed) or Metric Wrenches (ratcheting wrenches would be cool), 27mm socket (not usually included in a normal set, bought mine at Lowes) good quality Torque Wrench, breaker bar (I use my floor jack handle slipped over my 1/2" Craftsman socket wrench) and Circlip Pliers if you are replacing the drive shaft coupling.

Charlie sent this pic of his tools he used on the lube job. Yeah, that's his cell phone. Email me and I'll give you my number and be glad to help you during the process!

1. Put the bike up on the center stand, with the center stand on a 2x12 or similar size block of wood. This will raise the bike high enough to be able to remove the rear tire and wheel without deflating it. It's a good idea to use a ratchet strap to tie the center stand to the front forks to keep the bike from rolling forward and off the center stand when you are loosening the axel nut. You don't need to tighten the strap too tight, just enough to keep a little pressure on the center stand. Keep an eye on things as you loosen the axel nut to make sure you're not rolling the bike forward.

1A. There have been several suggestions from members on VN750.com that it is easier to first put the bike on the center stand, then have two 2x6's handy and tilt the bike to one side and slip the 2x6 under the center stand leg that is up, then tilt the bike to the other side and slip the other 2x6 under the other leg. If that works better for you, that's the way I'd do it. It certainly isn't easy doing it my way, but I'm used to it. Now we have options!
1B. Another option that has been suggested is to compress the front forks using a ratchet strap through the front wheel and over the handlebars while someone sits on the bike and forces the front forks to compress. Again, if that works for you, and you'd rather do it that way, I'm all for what works!

2. Remove the license plate. This will make more room for removing the tire.

3. Using a 10mm socket, remove the four bolts from the Right passenger foot peg mount. This will give you just a little wiggle room for your right exhaust pipe so you can remove the lower right shock nut.

4. Remove the cotter pin holding the brake drum torque rod nut (B), and then the nut, using a 14mm socket. Then remove the brake rod adjusting nut (A). To make sure I got this adjustment close when re-assembling, I counted the threads showing behind the nut, and made sure the same amount of threads were showing when I put it back on.

5. Remove both lower shock mount bolts with 17mm socket or wrench. Remove the shocks from their bottom mounts and let them hang. You may have to put your foot or leg under the tire to support it as you remove the shocks from their mounts. Then let the wheel hang low.

6. You can see that with the lower shock mounts off, the tire hangs plenty low to reach the axel nut with a socket wrench.

Here is where you need to be careful not to lurch the bike forward and off the center stand. Remove the cotter pin holding the axel nut.

Using your 27mm socket and breaker bar, loosen the axel nut and remove it. Lightly tap on the end of the axel with the plastic end of a screwdriver, or a piece of wood and it should pop loose. You can pull it from the right side and remove it along with the spacer. I laid out a shop towel on the floor to put these and all the nuts and bolts on. I especially wanted to keep the axel and spacer clean. Make note of what order things go here. From the right side, your axel goes through the frame, through a spacer, through the wheel hub and final drive (which has a spacer inside it) out the left side of the final drive, through a washer and then the axel nut. Remember this for re-installation!

7. From the rear, grab the wheel and rock it slightly to the right and it should come off the final drive. Keep a hand on the brake drum so it doesn't fall out, and put the wheel to the side.

NOTE: We've had one 750 owner that had the large circular ring clip come loose when he removed the wheel from the final drive. This ring clip is shown in this exploded view below. (OlHoss's edit 25 May 2013) It holds the drive coupling plate that covers the drive damper, has the 7 holes in it in the left side of the wheel hub. He didn't get it snapped back in tight and it fell loose again when he put the wheel back on the final drive, and when everything was tightened back up, it was pinched between the final drive and hub, locking the back wheel. Just something to be aware of! (Added 6-22-2011: Discovered by Wib714 in the KAW manual, this area is supposed to be cleaned and lubed, which he took photos of and I've added a link to his post of the photos and description near the bottom of the procedure, so make a mental note to come back here and look at the diagram below and you'll see the large snap ring that has to come off and the parts you need to remove, clean and what needs to be lubed and how it goes back together! Thanks again Wib!)
(Hope you don't mind me making the clarification of what the big snap ring holds in fergy. I can't believe I found even a small mistake in this thread after it being read by virtually every new member who checked in, and re-read several times by those performing the procedure on their own scoots!)

8. Remove the 4 nuts where the final drive is mounted to the swingarm/driveshaft housing and remove the final drive. Note the teeth on the spline of the final drive and the teeth inside of the drive shaft coupling. This is where the grease should be. Mine, unfortunately was dry, rusty, and full of rust powder the first time I went in here, which is why I'm replacing the final drive and drive shaft coupling, as well as lubing everything. You should also replace the o-ring that goes on the spline behind the teeth in this process.

(You don't get to see my rusty splines cause when I found them, I cleaned it up and greased them and put it back together so I could squeeze a few more rides out of it while I waited for my replacement parts to arrive.That was before I did this write-up with photos.)

You can see in the side by side photo, my old one on the left has nearly all the teeth worn off, and the o-ring is pretty flat. You can see that it was letting the grease out into the area around the spline. You can see the replacement final drive on the right and the fatter o-ring, and good teeth.

Because of the 10 image limit on postings, this is continued in Part 2...

 

[fergy]

Spline Lube Procedure Part 2

A close up of the bad teeth on the old final drive. You can really see the moly was leaking past the o-ring!

A close up of the teeth on the replacement final drive.

If you are only inspecting and lubing the splines, you can skip to section 11.

9. Clean the grease from inside the drive shaft coupling so you can clearly see the circlip. Using the circlip pliers, remove the circlip. I've read other write ups where this was a major pain to do but I feel like it might have been mostly to do with the wrong tools for the job. It might just have been my lucky day but the circlip came off first try.

I think it's worth having the circlip pliers. These are old and they changed the design so even if you found the exact model number, I don't believe it will fit anymore.UPDATE! See the photo of the Klein 73242 model below in my third post. They seem to be the best match, maybe even better than mine, and can be ordered for pretty cheap. You probably won't be able to pull the drive shaft coupling off the drive shaft because of the tension of the o-ring, but maybe you can. I used one of those right angle screw drivers, reached in there and slipped the blade between the drive shaft and coupling and gave it a little twist and it popped right off.

Here's a close up of the teeth inside of the old coupling. Nearly worn off.

Here's the teeth inside of the replacement coupling, looking good. I decided to just remove the coupling off the drive shaft I bought on Ebay for $20 because it's generally just the coupling that fails.

As you can see, the teeth on the drive shaft are in fine shape. There's no movement here so they "should" be in good shape.

10. Clean the teeth on the drive shaft, the coupling and the final drive making sure you remove all old grease and any other dirt or loose material before you install them. Slip on the new o-ring onto the drive shaft and dab a little grease around it to keep from damaging it when you slip on the replacement coupling. Slide on the coupling and push it forward until it seats. You will probably need to use a small screwdriver to push the spacer in around the area where the circlip will clip on. Use the circlip pliers to install the circlip. Make sure you get it all the way on. Again, use the small screwdriver to push the circlip if necessary to snap it in to place.

NOTE: Since you can only see the rear end of the driveshaft coupling when doing this job, I don't want to assume that everyone who reads this knows what each of these parts are. Here is a photo of a drive shaft from a Vulcan 1500. Our drive shaft is similar in the fact that it has the U-joint on the front end, and the coupling on the back end. This will give you an idea what's inside the drive shaft housing.

They call this front end a U-joint because it's basically two U shaped pieces connected by a 4 way joint that looks like a cross (+) that has bearings on each tip. This u-joint connects to the shaft that comes out of the back of the bevel gear housing. You can see the shaft on the right side of this next photo of the transmission area of our 750 motor. On our bikes, this joint of shaft to u-joint is well hidden behind the rubber boot. In the following photos, you'll see the rubber boot pulled back but the u-joint inside is hard to recognize.

Bevel Gear/Tranny area

11. Pull off the left side cover, and pull the rubber boot back from the swing arm from the back side, revealing the front of the drive shaft and the u-joint. Your hand should fit under the exhaust pipe to hold back on the rubber boot. While holding it open with your left hand, use the screwdriver or spoon or a toothbrush to rub some moly 60 around the teeth where the drive shaft slips on to the front spline. Just a little will do.

 

[fergy]

Spline Lube Procedure Part 3

Spray the u-joint with some white lithium grease. You can turn the drive shaft from the rear to cover all sides.
NOTE: If you accidentally pull the u-joint off the front shaft, it's not the end of the world! I did it and after a few moments of panic, I slipped my fingers of my left hand under it and guided it back on while pushing from the back end of the driveshaft with my right hand and it slipped right back on. So, no worries if it comes off. Actually, the earlier versions of the spline lube procedure have you pulling back on the driveshaft and removing it from the front shaft, greasing the teeth on the spline with moly, and then slipping it back on like I did it so if you want to go this route, it is probably best for the bike. Since there isn't the front and back movement there like there is on the final drive end, the majority of members feel like you don't need to pull it apart, so it's really up to you. Just know that it will go back on pretty easy.

This shows the coupling packed with moly. (Picture compliments of Sky Rider)
Thanks to Sky Rider for coming through with some killer photos for me after i dropped my camera toward the end of this process!

12. Using Honda Moly 60 or equivalent, scoop out about 1 teaspoon at a time and use your finger to apply the moly inside the drive shaft coupling at the rear. I used a screwdriver to push the moly in as far as I could, making sure no air pockets were left behind. Repeat two more times, getting a total of 3 teaspoons of moly into the fitting.

Showing the spline well coated with moly. (Picture compliments of Sky Rider)

Rub some moly around the teeth on the spline of the final drive. Don't forget to put on the new o-ring. Make sure the spring is seated onto the front of the spline and insert the spline into the drive shaft coupling. Once the teeth are aligned it will slip together. Finger tighten the four nuts attaching the final drive to the swing arm. You will feel some resistance from the spring as you squeeze this together and tighten the nuts finger tight. Using your torque wrench, tighten the 4 nuts holding the final drive to the swing arm, in a criss cross pattern, to 17.5 ft-lbs.

ADDED 6-22-2011: Dave (DACataldo) Pointed out that it is easier to go ahead and torque the 4 nuts holding the final drive to the drive shaft cover (swing arm) while you still have the wheel off and room to work, so I switched things up and moved that to the previous paragraph. Thanks Dave!! Good catch.

Also added 6-22-1011: Wib714 pointed out something that has been missing from this procedure from the beginning that I wasn't even aware of and I would have added it here but there is a limit to 10 photos in a single post, so if I added half his photos here, my next post with the rest would have been 4 pages down, so to keep from breaking it up, I am just adding a link here to Wib714's added steps so you can jump to it and jump back. Thanks Wib for your help in making this an ever growing, and improving document!!
Wib's added steps:

I put a coating of moly around the gear on the right side of the final drive where it meshes with the hub of the wheel, as well as the spacers and the axel shaft. I figure while you have all this laying in front of you, might as well clean and coat everything with moly.

13. Lift the rear wheel into place and mesh it with the final drive. Once it goes together, it should hold it's self in place while you put the spacer and axel shaft through the frame from right to left. Install the washer and then the axel nut finger tight.

14. Attach the brake rod and put on the adjusting nut with the amount of threads showing that you counted before removing the nut. Attach the brake drum torque rod making sure the torque rod bolt head is sitting in the recessed area on the back side, and put on the nut finger tight. Then tighten the axel nut to 80 ft-lbs. Make sure the axel nut cutouts are aligned with one of the holes going through the axel and insert a new cotter pin, bending the long end up around the outside of the axel and the short end toward the wheel. Tighten the brake drum torque rod nut to 22 ft-lbs.

15. Now you can re-install the shocks to the bottom mounts, and tighten the nuts to 22 ft-lbs. Replace the passenger right side foot peg brace. Install your license plate. Remember to check your gear oil level. Also, make sure the bike is in neutral, and spin the rear wheel to make sure everything is smooth. Now put the bike in 1st. gear and you shouldn't be able to spin the rear wheel. If all is good, remove your strap off the center stand and you're ready to ride!

ADDED 4-1-2011:

These are similar to the ones I used, even look a little narrower, and since they apparently changed the design of my Jensen pair, they might not fit into the coupling with the new design. These Klein 73242's can be ordered from here for about $17 plus shipping, but I've found the same pliers for less elsewhere so you might do a google search for "Klein 73242 and see what they're going for!

 

[clock152]

Love ya Brosinky!

 

[hayes2400]

like the detailed photos and directions, this will be a project very soon.

 

[fergy]

Don't wait too long. You might regret it.

Clock152, I hope that's you smooching that pretty brunette! Otherwise, I might be worried...

 

[The DEUCE]

Excellent write-up. :rockon:

I will lube my spline this weekend!

 

[clock152]

Don't wait too long. You might regret it.

Clock152, I hope that's you smooching that pretty brunette! Otherwise, I might be worried...

yup that is me.. and yes the wife is a bit younger than I...LOL:smiley_th

 

[dynajim]

Don't wait too long. You might regret it.

Clock152, I hope that's you smooching that pretty brunette! Otherwise, I might be worried...

Outstanding!!

 

[qweesy]

Great writeup, I am having a hell of a time trying to find some cheapy external snap ring pliers that will fit in the coupler my 50$ adjustable internal/External are too fat bought another set today all these parts stores have around here are the adjustable type.... they were thinner but still didnt fit to get the snap ring out, even home depot didnt have a set gonna try a couple other places tomorrow what brand are yours in the pic I cant make em out or the part number on the handle.

 

[flitecontrol]

I wound up getting a set of the cheap ones and grinding them down to fit.

 

[fergy]

Great writeup, I am having a hell of a time trying to find some cheapy external snap ring pliers that will fit in the coupler my 50$ adjustable internal/External are too fat bought another set today all these parts stores have around here are the adjustable type.... they were thinner but still didnt fit to get the snap ring out, even home depot didnt have a set gonna try a couple other places tomorrow what brand are yours in the pic I cant make em out or the part number on the handle.

Man, I've had those for 30 some years and I'm at work so no idea what brand they are. I think they might be PROTO brand, as they look like this one

and you can get them at Grainger supply: http://www.grainger.com/Grainger/PROTO-Retaining-Ring-Plier-5C600
Mine are so dirty and old I'd have to wait to look at them tonight and get back to you.

 

[BRET H]

Hello. I have been putting my bike back together from winter time downtime for much needed upgrades and fixes and after reading this thread and becoming super paranoid about drive line failure so......I decided to lube all the splines too. I used a mixture of Dow Corning Molykote grease and Loctite brand Krytox grease. My bike is an '86 and the splines at the rear of the drive shaft were coated with grease but I really don't think it was Moly(the grease was green?) The front splines were completely DRY!!!!!!, yet still in undamaged condition(very little wear!) Yes....I know I got very lucky!!!!!!! Now what tips I wanted to throw into this thread is that this procedure is pretty simple to do by yourself, UNLESS..........Your bike has had the center stand removed! My center stand was removed by the previous owner due to lowering the back of the bike 2" with 11" progressive springs/shocks. If you have no center stand.....this procedure really becomes a 2 PERSON JOB! :beerchug:Also unless you are replacing the seals in the final drive ring gear unit.....you do not need to drain out the 80w90 gear oil(unless it's time to change it anyway.) It will stay in the housing sealed when the gear housing is removed. Also if you have Vance & Hines Cruzers exhaust you will need to remove the rear exhaust hanger bolts to allow the exhaust to flex a little so that they can be pushed down to get the rear axle out.

 

[scuba]

great instructions, I will do it myself next time instead of having my mechanic do it. They only charged me $60.00. so it wasn't too bad.

 

[Gandalv]

QUESTION - Prepping for the spline lube procedure and am curios if it's worth the money to step up to 65% or 70% moly-di paste? Also, how much do I need? 8oz enough?

 

[fergy]

That's really up to you alone. Depends on what you are willing and able to spend. the Moly 60 we recommend is more than adequate in my opinion, and is a huge upgrade to what KAW used on them (when they used any!) and as long as you don't go over the recommended mileage between lubes, around 12K miles, the moly 60 should be way more than plenty. But, some people want to use the krytox and that's more than fine, if they can afford it. One small tube of moly 60 does at least two, maybe three lubes. I don't pack in so much it squeezes out everywhere, like I did when I did my first one, so I think I can get 3 lubes from the little 3 oz tube.

 

[OlHossCanada]

QUESTION - Prepping for the spline lube procedure and am curios if it's worth the money to step up to 65% or 70% moly-di paste? Also, how much do I need? 8oz enough?

That's really up to you alone. Depends on what you are willing and able to spend. the Moly 60 we recommend is more than adequate in my opinion, and is a huge upgrade to what KAW used on them (when they used any!) and as long as you don't go over the recommended mileage between lubes, around 12K miles, the moly 60 should be way more than plenty. But, some people want to use the krytox and that's more than fine, if they can afford it. One small tube of moly 60 does at least two, maybe three lubes. I don't pack in so much it squeezes out everywhere, like I did when I did my first one, so I think I can get 3 lubes from the little 3 oz tube.

I`m with fergy, the Moly60 is entirely adequate for the spline lube. The moly molecules actually get worked into the surface of the steel with motion and heat, and conditions it. The grease itself is just a "carrier" for the moly. It is possible for the grease in an old bike to be dried up and look really nasty, and the moly conditioning is still providing a virtually friction free sliding surface for the splines.

The manual calls for 17 ml of lube. That`s about 3.5 teaspoons. I think that is more than enough.

EDIT: Dec 30, 2012. Corrected conversion of 17 ml from 3 tablespoons to 3.5 teaspoons.

 

[1986vn750]

Just did a Spline lube on my 2001. The moment of truth was when i slid the Final off the shaft, and SAW GREASE!!! i was so relieved. i'll put some pictures on my photobucket soon.

 

[mistereman1]

Spline lube extras!

Every time I go to fix one issue with my Vulcan I get surprised by finding something else thats needs to be tweaked. I also have a couple of pics to add that may help others when they do this job. Sorry for the poor focus, buth I think they're good enough to get my point across.

I used bungies to hold the shocks and brake rod out of the way, like this:



The right lower shock stud was up against the muffler so I used a rubber chair foot to cover it and prevent scratching the chrome.



I used a broad pine board as a ramp/lever to help lift and hold the rear wheel while aligning the hub splines during reassembly. The square yellow bucket is full of kitty litter and it kept the ramp very stable. I knew cats had to be good for something!



When I removed the left side cover to to pull back the rubber boot over the u-joint the OEM wire guide just fell off. At first I thought it just cracked, but a closer look showed signs it had melted. See the little thin part sticking up on the bottom left and think of stretching plastic as it melts.




Turns out 2 of the three yellow AC wires from the STATOR also showed signs of melting. The top of the plastic cover over the male bullet connector had slipped or shrunk enough to expose bare metal. Either the 2 of them arced against each other or to the frame long enough to melt the plastic guide.



That can't be good for STATOR's health or lifespan. I advise checking them on your bike for similar problems. Replaced all three connectors. Put everything back together and went for short test ride. So far, so good!

 

[sause]

Thanks for this guide. I finally was confident enough to do it after looking through the pictures multiple times. Thank goodness that the splines were is perfect condition and the o-ring was in good shape too. Not bad for 25 years. :smiley_th