Sudden power loss to final drive

[Troll]

I know you probably don't want to think about this possibility, and the slipping clutch seems more likely, but the dealer I work with told me that the failure of the spring (in yellow) could cause the trans to pop out of gear/clunk. Early models were more liable to have this failure. This thing works like the compensator sprocket assembly on a Harley, and is coupled with the rubber cush drive in the rear wheel. 

[chief]

You know you are talking about two different things here... the fluid in the hydraulic clutch (brake fluid) and the "wet clutch" fluid which is the engine oil.

Since you replaced the clutch levers, I suppose there could have been a problem with the combination of old hydro fluid and lever position... but honestly the fluid in the clutch line only impacts disengaging the clutch... when released other forces - spring pressure - holds the clutch engagement.

I'd keep an eye on it.

[Redbeard]

I did replace the fluid yesterday using the MityVac method (absolutely recommend it to anyone). It was definitely due (dark brown fluid). I went for about a 35 minute spin to make sure everything was okay. The first ten minutes were great... actually felt like a brand new bike! Smooth shifting with no clunks when I kicked between gears. It accelerated nicely, with no crazy revs at a steady throttle. Then, it started doing the clunking. It was noticeable, but not any worse than the first day I bought it.

Seems like it's back to "normal" though. Thank you very much for giving me the tips! 

Redbeard

[Redbeard]

Thanks for the advise Chief. I'll get on it this afternoon.

[chief]

Older drifters suffer from a weak clutch spring and single holder which allows acceleration of wear on the spring. I'd satisfy myself that the clutch is working properly, that the lever change hasn't changed the release point and that the shaft is working properly. I'd also check the oil in the rearend to ensure there is no evidence of metal etc in it. (And I'd replace it if you haven't done so yourself or know for sure the previous owner did so.)

At that point, I'd probably open the clutch box, measure the clutch plates and replace the spring and holders with those currently used for all 1500/1600 Vulcan clutches.

Do some investigative work yourself before you start taking stuff apart. If you aren't familiar with slipping clutches get with someone who does... it might help you eliminate that as a potential problem.

[Redbeard]

Thanks for responding Chief! Funny you should mention both of those areas...

I haven't done anything to the clutch itself. However, I did change out the levers sometime after Christmas (got new blades). I didn't tamper with the clutch/brake lines though. I just unscrewed the bolt holding the blade in-place, took off the old blade, and installed the new one. The springs and screws were reseated properly.

The drive shaft looks and sounds fine. Although again, I added a new chrome cover sometime after Christmas. It was originally made for a VN1500E, but I cut a notch in the rear end of the chrome piece so that it would fit around the tab holding our rear electrical junction box. The chrome cover attaches to the shaft with two zip-ties. It was a cosmetic modification only... no restrictions/jostling/damage done to the shaft.

Oh, I forgot to add some background on my bike: 99 VN1500J, 11K miles, regular oil changes (no other maintenance performed so far)

[chief]

Two areas I'd check... shaft and clutch. Have you done any work on the clutch.

[Redbeard]

Hey Guys and Gals,

Bit of a problem here. Like usual, a great 35 minute ride into work this morning. But this afternoon was a different story. About a quarter of the way home, I had an intense loss of power to the rear wheel. It started as sporadic revs when I applied steady throttle. I tried varying speeds, gears, and rpms... no change. Then it manifested itself into total power loss, like coast-style. The engine was still running smoothly and revved when throttle was applied. But there was nothing at the wheel. At this point I was at a complete stop. So I tried everything. I even let the clutch out completely... nada. Had to leave her on the side of the road. Came back to get her an hour later and voila. Still not up to snuff, but I limped her home.

I'm taking any advise you might have... Because I'm sure not riding back to work with the chance of being stranded on my mind!

Thanks!