DAR part check

[biodegraded]

I've not had the chance to compare my engine sound to another Steamer, but I was pretty sure kitty had a case of the DARs. Now that I'm doing a total refurbishment, I'm getting around to checking.

Yup - the bolt on the clutch side is sheared. Fortunately it failed about 3/4" down from the head which left enough bolt to stay captured in the alternator shaft hole by the sprocket face; one hates to think what mischief could have been caused if the head had dropped into the accessory gear and clutch space.

Anyway, I'm looking at Bike Bandit and presume the part I need is this one (link):

ALTERNATOR SHAFT SPARES KIT
ENG NO 56684 AND BEL0W   p/n 1388050   $142.78

Their part number of course doesn't match Triumph's, but I think this is it. Confirmation yay or nay welcome. Other parts needed, like alternator cush rubbers, 3 of 4 which are crushed, are obvious.

Cheers-
Keith

[Mustang]

and read the sticky threads there are some good ones for repairing the DAR.

cuz you don't want to lose the sprag clutch down the gearbox or you'll be splittin cases

[biodegraded]

I'll give them a careful read. My thought, was to drift out the old shaft with the new one, but perhaps there's a better way. I sure don't want to be splitting the case!

[Mustang]

I'll give them a careful read. My thought, was to drift out the old shaft with the new one, but perhaps there's a better way. I sure don't want to be splitting the case!

thats the way it's done............ works great

it's bad enough as is, you get to pull your clutch apart .

[biodegraded]

Oh, I disassembled everything yesterday. I just need the part now.

I toyed about 5 seconds with the idea of putting in a proper diameter dummy shaft (sans splines) and seeing if I could remove the broken off bolt in the existing shaft and putting harder replacement bolts in, or even cajoling one of our machinists at work to bore it hollow for a single long bolt like Triumph's updated shaft.

Naaaaa... I'd rather just get the manufacturer's proven replacement.

Next up: valve clearances. Oh joy - haven't done under-bucket shims since my '83 Kaw 650... [edit] - doh! I just looked at drawings and see they're over-bucket shims.  :o

[nightrunner]

Make sure to use threadlocker when you assemble; and on the alternator side too.  The bolt break is caused by the coupler hub having the tiniest bit of play on the splined end of the shaft.  As torque goes back and forth between leading and trailing throttle, that bit of play allows the hub to rotate a fraction of a degree on the splines.   Now add the action of the lock washer.  Ever so gradually over thousands of miles the bolt gets tighter and tighter until it breaks off.  The factory bolt is DIN 10.9 (U.S. grade 8 equivalent) so its not due to a weak bolt.  You can go to a 12.9 aircraft grade bolt if you want but the key is make sure the bolt cant get tighter.  One trick is to use something like JB Weld on the splines to take up the bit of wiggle.   Another is the threadlocker.  And its up to you but when I did mine I got rid of the lock washer and used a flat washer.  Good luck with the repair.

[biodegraded]

I just got the OEM repair parts, so know some of what I'll be doing this weekend.  :)

The new bolt has some kind of purple thread locking compound on the end. The kit uses flat washers on both ends. I'm hesitant to form a JB Weld bond between the coupler and the shaft. Though the upgraded parts should last the life of the bike, what if I need to take it apart again? Is that a worry over nothing?

Thanks for the reply,
Keith

[Mustang]

it's the coupler halve on the alternator that usually rattles like hell , worse when the bolt head is broken , don't use JB on the engine side  :shock:

once you have the new and improved shaft with one bolt installed it is the bolt in the alternator shaft that breaks all the time ............  :roll: seriously

The new bolt has some kind of purple thread locking compound on the end.

blue =removable
purple = sorta removable
red = no fuckin way it's comin apart without a torch !

[MIMbox]

Loctite Rocks, ( and of course, Locks)....and is an engineering solution, not a bodger's delight

http://www.loctite.co.uk/uke/content_da ... enn_08.pdf (http://www.loctite.co.uk/uke/content_data/LOCT.C.G.final_english_version_genn_08.pdf)

[biodegraded]

Now that the forum has settled down, here's my report on How I Spent My Summer Vacation. (Holiday to you King's Englisher types  )

The brown truck made the drop:


Here's a flash shot of just the parts:


Thanks to the various links / faqs on this site, it was trivial to drift the old shaft out with the new one. Here is your alternator shaft on DAR. Any questions?


I gave some thought to the comments:

One trick is to use something like JB Weld on the splines to take up the bit of wiggle. Another is the threadlocker.

and:

it's the coupler halve on the alternator that usually rattles like hell , worse when the bolt head is broken , don't use JB on the engine side

once you have the new and improved shaft with one bolt installed it is the bolt in the alternator shaft that breaks all the time

I guess I gave the impression that I don't know what thread locker is. That's not the case, we use it by the gallon at work and I usually have fresh blue at home. I got thinking Loctite might make a product specifically for shaft fittings, so I went to my company's motherload and found this:


It looked to be just what the doctor ordered so I took one of the bottles of it to try out. It's a light green. After consideration, I decided I'd use the stuff on both couplers on their respective splined shafts. I understand if I have to mess with the engine shaft I'll be limited to drifting it out the alternator side and will need a torch to 250F to release the thing, per Loctite's specs. Anyway, here's the de-greased engine side coupler:


Here's the alternator before the job in case you didn't know what it looks like.  (Not bloody likely - I expect most of us a well acquainted with the monster) 


Anyway, the clutch is all buttoned up again and all that remains is getting the alternator in. Getting the vanes and cush rubbers all lined up seems to be a bit of a trick and I didn't have the patience to fuss with it at the end of the repair session.

So there it is: one less DAR-afflicted tiger.
Keith

[matts23]

I don't have a steamer, but I hope that lasts a long time.  I use Loctite 609 at work to hold press fit bearings in an open side frame when they are worn and spin in the bores.  It is tough stuff.  I wouldn't want to get anything threaded back apart with it on there.