I just ordered a new shaft for 35 bucks, with a coupler. I asked them so check it for me for wear, and they say it's very good. It comes from a vn700 with about 2,5k km's on it
common problem rear?
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I just ordered a new shaft for 35 bucks, with a coupler. I asked them so check it for me for wear, and they say it's very good. It comes from a vn700 with about 2,5k km's on it
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Comparing your coupler pic to others, I see what's going on now.
Your coupler is completely missing the outer half of the splines. When the suspension moves, the driveshaft moves and the splines engage and disengage.
A good coupler only has approx. 1/4" or a bit more of area with no splines at the very end. Your coupler has something like 1.5" to 2" of area with no splines.
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Your coupler is completely missing the outer half of the splines. When the suspension moves, the driveshaft moves and the splines engage and disengage.
A good coupler only has approx. 1/4" or a bit more of area with no splines at the very end. Your coupler has something like 1.5" to 2" of area with no splines.
Ah I see now. Is it maybe possible that the coupler is backwards or something? previous owner told me that he changed the drive shaft a year ago, but the bike had been sitting since about 8months now because of the problem. I haven't seen the other side that's on the shaft tho, so maybe it's a silly thought.
Or should I try and get a coupler like the picture you sent?
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It wouldn't fit backwards. The other end is different, snap ring retainer, etc.
Just find a coupler for the 750 and post a link or pic for it. We can see if it looks ok.
Maybe that coupler wasn't so great when the PO installed it?
if I look at the second picture they have on this website. it looks like that part is outwards what I posted a picture of. but the new (2nd hand) shaft with coupler and spring is on it's way, maybe that's the one outside what you posted. then I can take this coupler off and check the other side if that seems to be what I ust thought
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Oh hell, maybe your's is installed backwards!
My apologies, I haven't had to deal with this problem, so haven't had the coupler in my hands.
The link you just posted shows one set of coupler splines is deeper than the other. I would believe those shorter splines go onto the driveshaft.
You haven't removed the coupler from the shaft yet? I think it's installed backwards.
This can also explain why it was slipping but the splines aren't destroyed totally.
Exactly my thoughts! My brain started cranking and thinking about it that would be such a stupid mistake from the PO.
I tried tapping (outwards towards where the rear drive should be) on the coupler to get it off, but it wouldn't budge at all. Could that be the snap ring you were talking about? That's maybe binding inside?
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Absolutely, the retainer ring holds the coupler onto the driveshaft. You need a set of snap ring pliers that will reach inside the coupler and still open enough to engage the retainer ring. You have to remove the retainer before the coupler will come off.
It makes sense that the shallow splines belong on the driveshaft and not the rear gear, because the driveshaft goes deep enough for the retainer to engage.
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Well ... dammit.
You're right Thorn. The deep end does go to the rear.
Should've looked here first, scroll down.... (wasted splines)
The Spline Lube Procedure Part 1
This Site is Awsome, just lubed spline I want to thank everyone on this forum for the outstanding job of suppling so much valuable info. I purchased an 05 750 last July with only 5k miles. The bike is mint and I love riding it. It gives me a break from riding my Goldwing. I waited untill...
www.vn750.com
so.. the coupler is not backwards? and the problem should be somewhere else? I'm still changing out the shaft with coupler and spring and all. because the coupler seems to be damaged.
but now I'm back to figuring out how this happened, since it isn't backwards and all
but now I'm back to figuring out how this happened, since it isn't backwards and all
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Yes, no the coupler isn't backwards, my mistake.
You said the spring didn't have much tension?
No damaged splines on the front? If the spring was weak it might let the front slip off the splines.
Replacing it all should do it.
The splines from the final drive and the axle-coupling (front), and the bevel-gearing shaft looks all fine and ready to go. The spring was just gunked up with grease and some metal shavings from the splines of the coupler. So maybe it was just the spring that failed.
Hopefully I'll get the shaft ASAP, so I can replace and drive it again
Hopefully I'll get the shaft ASAP, so I can replace and drive it again
Your current coupler is installed properly. All your symptoms stem from wear on the splines of the coupler. It is c-clipped in place, so you'll have to remove that clip to get the coupler off the drive shaft. It's a PITA because it is so deep. Was still easier for me than replacing the whole drive shaft. The splines between the drive shaft and the coupler do not move, so they should be undamaged. The splines between the coupler and the final drive DO move, so a little wear can cause some overlap, crunching, and jamming. The spring is quite stiff (takes up slack in the drive shaft when going over pot-holes, roughly the same job as suspension springs), so if it isn't broken, it is likely still good.
The original wear on the coupler was probably due to inadequate lubrication, and the sliding of the splines back and forth as your suspension moved (as intended) wore away the material (not intended). The PO probably replaced the final drive, but not the coupler, added lube, and shipped it. The (newish?) final drive splines are showing wear due to slipping past the worn splines on the coupler. The damage isn't too bad, so a new coupler should engage well enough to not slip. The mating surfaces won't be perfect due to the small amount of damage now present on the final drive splines, so wear will be slightly accelerated, but should last a long long time if kept properly lubed.
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He's already got the swingarm removed.
just to put the info on here again:
PO is a good friend of mine
PO had the bike, last march 2022: replaced the driveshaft because of a noise, noise was gone. PO drove again.
PO messed up the bike in about May/june 2022, this noise appeared again.
PO tried looking for the problem, instead of going to a shop, couldn't find it.
PO gave the bike for free to me in Nov 2022, he bought a Vn2000. He gave the bike because I'm a mechanic.
"If you can fix it, you have a free-ish bike. If not, you can just sell it."
- I replaced the final drive with PO in december 2022, problem was fixed and I drove a few meters on our property (no license yet)
- few months later, March 2023. I drove again, a bit bigger lap, and noise got back
PO is a good friend of mine
PO had the bike, last march 2022: replaced the driveshaft because of a noise, noise was gone. PO drove again.
PO messed up the bike in about May/june 2022, this noise appeared again.
PO tried looking for the problem, instead of going to a shop, couldn't find it.
PO gave the bike for free to me in Nov 2022, he bought a Vn2000. He gave the bike because I'm a mechanic.
"If you can fix it, you have a free-ish bike. If not, you can just sell it."
- I replaced the final drive with PO in december 2022, problem was fixed and I drove a few meters on our property (no license yet)
- few months later, March 2023. I drove again, a bit bigger lap, and noise got back
Joined
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431 Posts
Be careful here. Don't do as I did. Do not use Moly lube on the wheel splines. Check out this video I made here for my Youtube Channel. If you use Moly lube here on the wheel splines, you'll make a mess of your rear wheel. Instead, use some high temp wheel grease like what I show in the video.
As a former car-mechanic I still have some spline-grease left from my old job. It's rated up to 300degrees celcius and made specifically for spline-connections like driveshafts. But I'll check out your video for good measure
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