Drive Train Problem ERRR! Help!

michaelgrav

michaelgrav

New Member
I have a Nirve cruiser with a jackshaft assembly with an interplanetary Shimano 3 speed rear hub. I am not sure which is malfuntioning the hub or something to do with jackshaft assembly??? I had this hub since December and the same hub for over a year and have ridden this bike mostly on a daily basis. When the hub fially died I replaced the hub with the same hub which lasted only until about 2 weeks ago. The hub seized spinning the rear nut completely off, I retightened it only to happen 3 times.
I have since replaced the hub twice, first with a Sturmy Archer 5 speed and could not get it to gear properly under power but without the engine it worked normal.
I Bought another Shimano 3 speed like the one I was origially using thinking it was a bad hub.But same as the Sturmey Archer It also will not run under the power of the engine without skipping and throughing the chain off. Damn!
I can't seem to get it to function with either hub under power.
The Bike works great without the engine and go thru all gears without slippage. Once the engine is engaged it skips real bad, like its not all the way in gear??
I took apart the jackshaft assembly, checked all the gears, keyways and chains...
I am stumped.
Any suggestions I have had this bike for 2 years and never ran into such a problem. Its only been this past 2 weeks I have run into this. I tried 2 different hubs replaced by a local bike shop and have had no luck and the problem remains that the drive train won't work under the power of the engine. What am I missing?
:-||
 

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This isa tough one, not all the symptoms match o_O

Like a hub havin' engagement issues shouldn't throw the chain... and shouldn't be any different under pedal power vs gentle engine use...

Is that a recent pic of yer bike? I only ask 'cause there doesn't seem to be much wear. Also, it appears like you might have engine/shiftkit/frame alignment problems;

22621d1270101554-drive-train-proble.jpg


While ya might be usin' the extended offset intake that was provided w/the CNS which would explain why the airfilter is so far off-center, I noticed that the lil second gear is kinda hanging off the end of the shaft, the exhaust clamps used for rear mounts seem slightly crushed, and (this could be just the pic) the shiftkit side plates seem bent outward slightly...

Where is the chain jumping off when it bails on ya?
 
I think everything looks quite acceptable. I think everything that BA commented on, while definitely not optimum should not be causing any issues and are probably related to the photo distortion. I think it is something with the hub. Everything else looks fine. Knowing what chain is coming off may help as BA suggested.
 
Then I can't see how it'd be the hub... I could be wrong, but I'd break out a straight edge & square and see of those two sprockets are aligned *shrug*

Wouldn't hurt to check bearings and shaft, even the freewheel sprocket/bearing play while yer in there... but defo listen to Ghost0, it's his baby lol


Awesome bike BTW lol - the forks look particularly sweet on that ride (^)
 
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I don't see how I can get to brand new hubs that are bad in a row? the freewhell has minimal play but it always has. The sprockets are aligned.
 
If the sprockets are not aligned then it could cause the skipping as the chain is trying to come off. As BA said, check the alignment. Make sure the shaft is square both front to back and up and down and that the sprockets line up.
 
Thanks Ghost I have off tommorow and plan to tear the whole jackshaft assembly apart a realign the whole thin again.
 
I'm not sayin' they're bad BTW... but there's gotta be something hinky there, it's the smallest chain from jackshaft's little sprocket to the 44t freewheeled crank sprocket - right?

Thing is I dunno what the problem with the hubs could be, that chain flying off I can't see as related - even if you detonated a rear hub that 'un should stay put...
 
I think possibly the jackshaft assembly needs some staightening but I ordered new housing from SBP and gonna have someone do it in stainless with a some extra strengh. The one I have now is 2 pieces, I had someone weld the right side and the part of the housing that goes bolts to the bike frame as one piece. That assembly has taken 2 years of straight cruising and 3 motors worth of abuse.. LOL: I was trying to rush this fix but think I I'll ltake the bike off the road for a week, sit back and examine it more before I make too many more moves.... This addictive hobby can become a money pit, and it's never been off the road for more than 3 days ( My daily commuter...work groceries etc. oh beer too) It can be a head ache but I love it!
 
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Two years of usage w/o bein' parked fer more than three days? Awesome!

I'd say she's done well and deserves some attention heh ;)
 
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