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Discussion Starter #1
Hello! How I love the perpetual project of the old bike.

So, I was cruising around, having a good time today, and was close to the end of my ride. I got off the highway and came to a stop, as I was going to take off, I shifted down into 1st gear and it sounded wayyyy clunkier than normal. I thought that was weird, but continued on. I went forward, and then noticed that anytime I was going at a decent RPM and let go of the throttle, I would get that clunk again. It wouldn't happen every time I went into first gear, only a couple times. Also happens every time I down shift. Even with the bike off, if I have the clutch engaged and roll back, I get that clunk. Def doesn't sound good.

Some posts seem like it might be final drive, but I'm not sure. Any ideas?
 

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Not the final drive but the coupler at the rear of the driveshaft that connect to the final drive. Unfortunately a lot of the time the splines on the final drive get hurt as well.
 

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definitely good idea to look at the final drive.

in my case what you described progressed to one louder clunck after which power to the wheel was lost. walking the bike home wan't fun.
 

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Discussion Starter #4
Looks like I've got some adventures ahead. I'll tear that sucker down and report back what I find. Thanks for your help!
 

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Discussion Starter #5
Anyone know where to get a coupler only? Seems like I can get an entire drive shaft w a coupler attached to it for cheaper than finding a coupler ($38 shipped). What do you guys think?
 

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Ebay is usually the best bet for either one, but complete shafts are often cheaper than the coupler by itself. Just look at the splines real close. $38 isn't too bad for the whole shaft.

Those parts are pretty expensive to buy new.

Make sure to get high moly paste.
 

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yea, spockster is right. the coupler is 80+ (new) last time I looked which was when mine failed. I got full driveshaft with coupler for about 30$ shipped from ebay (I believe it was a motorcycle recycler). make sure to check all the pics to see of they show the splines inside the coupler, and if they dont show them, dont buy it. the driveshaft itself rarely (if ever) fails, its always the coupler. should be nice and clean (no rust) with nice square splines. Same goes for the final drive if you need to get one of them.
 

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Discussion Starter #8
Alright, went ahead and pulled the final drive off. As far as the connecting rod goes, it seems like it's shot with pretty much no teeth remaining. As far as my final drive being bone f'ing dry, it seems like it looks pretty good, what do you guys think? Please note that when I tried to take the left side top bolt out, it seems it threaded out of the final drive. I'm assuming I just tighten the entire thing back on and I'm good? Maybe some blue loctite? I have no problem getting some new hardware being that I nearly stripped one of those final drive bolts and I'll need to replace that anyway.

It seems I pulled the shaft out from the engine side :/. How difficult is it to get it back in there? Seems like the rubber thing covering it is very resistant to me moving it back for me to take a look, any suggestions?

Final question! I'll be ordering a new drive shaft since that seems to be the cheapest way to get a connecting rod. When it comes in, should I remove the connecting rod and transplant the healthy connecting rod onto my existing drive shaft, or should I just install an entirely new drive shaft?

Thank you for your help!
 

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Discussion Starter #9
Any advice on any of these? The top one looks good especially for the price, but it says it's off a vn750 CUSTOM whatever that means. Any chance this is a custom drive shaft/rod? Looks like oem to me.

https://www.ebay.com/itm/01-Kawasaki-VN750-Vulcan-CUSTOM-Rear-Drive-Shaft/254622788367?hash=item3b48b36b0f:g:72sAAOSwy8Ze4l6n#viTabs_0

This one is a little more expensive but teeth look great overall.

https://www.ebay.com/itm/1992-Kawasaki-VN750-Vulcan-OEM-Driveshaft/153961459193?hash=item23d8d16df9:g:LRoAAOSwFLReyBSo

Thanks again!
 

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As long as the front u-joint on the replacement shaft feels ok, I'd just use the whole shaft instead of swapping couplers.

First shaft looks cleaner but second one looks to have a lot better splines.

The splines on the final gear took a beating, but should be ok with a good coupler and moly grease.
 

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Discussion Starter #11
Alright got some Moly M77 paste and the first one due to cost and delivery time. Hope they mate up well!
 

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Discussion Starter #12 (Edited)
So, I tried going the remove the bevel case route, but I couldn't get that damn thing off. Worst part is, I"m pretty sure I stripped the threads on the engine side with one of the bolts. I'm so sick of this bike, anyone in SoCal looking for a used vulcan? Rides great and have all the parts to fix it, but I'm just over it. I'll sell it on the cheap.

One question I have is whether or not its possible to use loctite and a gasket sealer on stripped internal threads? I can't even get the bevel gear case out, let alone get in there to tap a new hole (not even sure if there's enough space for this). Definitely feeling in over my head.
 

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Hmm, removing the bevel gear assembly is pretty straightforward... remove the clutch cable lever, then the bolts (7 I think I don't remember off top of head) and the spring inside it will push it off.

I found it harder to install than remove due to lining up the driveshaft and fighting the spring at same time
 

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We had a member in California but he hasn't been seen for quite a while. He had two Vulcans.
Think Tanner was in Dana Point.

Haven't looked at our member map in a long time, don't have the link to it now.
 

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Discussion Starter #15
Alright got a couple days to cool down a bit. Covid stress and bike stress = needed a break.

When trying to pull the bevel gear case, I couldn’t clear the rear exhaust. I tried shimmying as much as possible but I couldn’t clear it through. Is this possible without pulling the exhaust? Seems like pulling the exhaust off is an inevitable can of worms w a 20 year old bike. There is still the option of trying to pull the snap rings off but that seems more or less impossible to me lol.

Second question is about the stripped threads on one of the seven bolts. Do I need to retap this? Could I possibly get away with a slightly longer bolt if there are some extra threads back there?


Thanks VN750 crew, your help is extra appreciated.
 

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Can you pinpoint better for me which bolt is stripped?

You don't really need to pull the bevel gear. You can slide the rubber boot back in order to get the driveshaft back in place. The boot is difficult to manipulate, I had an extra pair of hands to put it back on.

You need snap ring pliers long enough to reach the back of the coupler.
 

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Seconding what Spockster said. If you're replacing the whole shaft, the old shaft should fall off the splines coming out of the bevel gear with a little wiggling and pulling. Getting the new one on isn't "easy", but it's not too bad if you reach a finger in past the rubber boot/elbow that covers the gap between the bevel gear and the shaft housing.

As for the snap rings, they're a PITA, but can be done either with the nice, long snap ring pliers, or with the cheapo set from HF if you put them together so they act like those extendable fire tongs and grind off some of the shoulder of the tips. PITA but works if you don't have the high quality tools on hand (or ever $$$)
 

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The problem is ... The shaft comes out of the front of the swingarm, and I think the engine is still in the way even with the bevel gear removed.

Best to just swap couplers if the above is true.
 

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Discussion Starter #19
I got a snap ring tool, and I can get it inserted into the two holes of the snap ring and get it to pull apart a bit, but that's about as far as I can get with it. I've attached a photo and squared the bolt that has stripped on the engine end.

Thanks Guys!
 

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Sometimes, you have to adjust the pins on the end of the pliers so they're farther apart when spread. If yours is adjustable.

Does the hole on the engine still have good threads?
 
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