DAR-how do I know?

[1speed]

Just how apparent is DAR. This is my first Triumph. I have had numerous Hondas, Kawasakis and a 98 Buell S1W. The Tiger has more mechanical  noise than the japanese bikes, but how much is normal? Is there an easy way to check if the bolt is sheared?

[offtheback]

I wish I had the know how to post sound..  Hope you located the hepco's.  Anyway, the bikes are a bit noisy and have a bit of a whine but if you have the
DAR you will notice it on idle.  The bike has a very pronounced diesel sound on idle and up to about 3500 rpm (where the bolt spins to the outside and no longer rattles around) then disappears.  The noise and vibration are on the top of the clutch where the alternator is driven from.  Your bike has pretty low miles so you may not have it??  Easy way... NO..  You have to remove the alternator which means covers, tank, carbs, airbox, coolant line and clutch master..  It only takes about 1hr to remove all of that so it is not that bad.  Look at the post by abruzzi on what to look for if the bolt may be on the clutch side...

Abruzzi and another member have recently performed this upgrade and I will be doing the same in the next few weeks..  Hopefully abruzzi will post pics when he gets time...

[abruzzi]

My plan is to do mine this weekend, and I'll bring my camera for pics.  There is a lot of half information online, but I haven't found a good clearcut doc on it, so hopefully I'm be able to rectify that.

I tried to get good sound recording, but it didn't really come out.  I'd describe it as this:

- the diesel sound at idle is normal
- the DAR sound is a pronounced rattle, under load (not really noticable when revving the engine in neutral) up to about 3000 rpms.  My rattle cuts off quickly at 3000--no gradual fade out.

My brother also showed me the mechanic trick of using a long screwdriver as a stethoscope.  When doing that the noise was noticeably pronounces when you put the stethoscope on the alternator.

Geof

[abruzzi]

My plan is to do mine this weekend, and I'll bring my camera for pics.  There is a lot of half information online, but I haven't found a good clearcut doc on it, so hopefully I'm be able to rectify that.

I tried to get good sound recording, but it didn't really come out.  I'd describe it as this:

- the diesel sound at idle is normal
- the DAR sound is a pronounced rattle, under load (not really noticable when revving the engine in neutral) up to about 3000 rpms.  My rattle cuts off quickly at 3000--no gradual fade out.

My brother also showed me the mechanic trick of using a long screwdriver as a stethoscope.  When doing that the noise was noticeably pronounces when you put the stethoscope on the alternator.

Geof

[nightrunner]

I've been meaning to do a write-up on it for some time.  I can only atest to the alternator side though; have not done the other side.  Anyway IMO the noise is too loud to be from the broken bolt head.  I think it comes from the cush drive vane rattling on the splined alternator shaft.  Actually there are two possible bolts on the alt side to break; one holding the vane that drives the alt, and the other on the alt shaft.  It is the latter that usually breaks but both are accessible by removing the alt.  

You do not have to remove the tank and all to get the alt out.  Pull the seat and left side cover.  Disconnect the battery.  You'll need the correct Torx bit and fairly long socket extension.  Three Torx bolts hold the alt on with one of them also holding the main ground wire.  Also mind the electrical connector.  It will take some muscle to wiggle the alt out.  You'll see a little squirrel cage in the center of the rubber cush pads and that's where the bolt head and washer will end up.  The biggest challenge will be getting the broken bolt out of the end of the shaft.  

Some people have reported that DAR happens a second time.  I think this is because there is a tiny tiny amount of jiggle room on the splines.  After a few thousand miles of leading and trailing torque on the shaft, the lock washer grips the bolt head and slowly tightens the bolt until it breaks.  Anyway what I did was to use some JB Weld on the splines to take up the slack.   The factory bolt is pretty tough; DIN 10.9 which is the same as US grade 8.  I found some DIN 12.9 aircraft bolts in the same size but a bit longer.  I'll mail you a couple if you're in the US.  Or you can buy a box from McMaster Carr.  They are M6-1X20mm.  I think the stock bolts are 16mm but here was plenty of extra threads in the alt shaft.   Anyway be careful not to pinch the big O-ring on putting the alt back in or you'll leak oil.  If you have high miles, you may want to look into replacing the cush bumpers.

Post back if you have questions.
Cheers

[nightrunner]

I just wanted to add to be very careful with the alternator if there is a broken bolt in the shaft.  Last I heard the alt is about $800 and that was years ago.  If you are not skilled with easy-outs, then take it to a real machine shop (as opposed to a bike shop) and let them extract the bolt.   They have the tools to drill the bolt in the exact center.   Good luck with it.