I should know better

[canuck750]

Riding my V7 Sport last night at the end of the evening and close to home I suddenly felt a brief decelaration and a high pitch squeal, it felt like a brake grabbing but it was very short lived and then the generator light came on. I was only a couple blocks from home. When I got in the shop I looked around the bike and noticed what I though was a stone stuck to the alternator cover, turned out to be the end of a bolt coming through the cover.



I had set the timing on the weekend and rotating the alternator with an alan key socket I snapped the rotor bolt. I made a new rotor bolt from a stainless steel bolt, the First Mistake, then I did not use locktite, Second Mistake.

While riding the bike the rotor bolt worked loose, then along with the weight of the rotor the bolt cut through the cover until it jammed at which time is snapped the bolt, leaving a few mm of bolt in the crank. The rotor no longer tight to the crank worked free of the grasp of the oil seal and hot oil saturated the stator and rotor negating the charging system,



I should have waited for a proper steel rotor bolt and torqued it with locktiite. Stainless is too brittle and a lack of locktite proved fatal.

Sucks!

[pete roper]

Ouch! I've seen that several times over the last four decades! You're not Robinson Crusoe on that.......

Pete

[oldbike54]

 Yeah , not the first time that's happened Jim .

 Dusty

[canuck750]

Well it's somewhat comforting to know it's not a unique mistake, the V7 Sport sure makes a great drill press! 

Basically a flat headed fastener cutting through a couple mm of aluminum in seconds is pretty impressive!

[oldbike54]

Well it's somewhat comforting to know it's not a unique mistake, the V7 Sport sure makes a great drill press! 

Basically a flat headed fastener cutting through a couple mm of aluminum in seconds is pretty impressive!

 How many drill presses rev to 5K revs ? 

 Dusty

[rodekyll]

Not the same thing, but In the vicinity . . .






I made the hex key too long.   

[n3303j]

Hope you didn't damage the taper on the crank nose.

If the taper is undamaged assemble with a thoroughly dry taper (cleaned with  alcohol or brake cleaner).
Use only the proper grade steel bolt (and NO Loctite) tightened to 14 foot pounds and you will have no problems.

Meanwhile rotate your engine using the rear wheel with the transmission in the highest gear. It saves a lot of aggrevation.

[Aaron D.]

I have never seen this happen! But it was the reason I always used the rear wheel to rotate the engine. Besides being too lazy to take off the cover for the job.

[Dave Swanson]

Man that hurts looking at it!   

[chuck peterson]

Look in McMaster Carr catalog for " tap extractors" for the screw broken off in the crank...

Don't ask, it's a long story...

Can't use just any bolt, go stock, no loctite

Whoops sorry, wrong story...I snapped a tap when I tried to clean the threads on the crank...tap extractor got it out for me

[Groover]

Up to last year, MG Cycle used to carry a replacement rotor bolt, Bosch original supposedly. I'm not seeing it on their site anymore, so maybe no longer available. The one they sold was "gold" in color, the original Moto Guzzi one is black. Long story short, the new gold one broke while adjusting the valves when turning the engine over with the Allen wrench; I was lucky to get it out by removing the rotor then I was able to grab the broken bolt with pliers. I've also started using the turn-the-wheel-while-in-gear method to turn the engine over now.

Try to find an original bolt if you can, even if used. I think they are class 10.9 in the harness scale (don't quote me), but should be at least 8.8. I personally wouldn't use Loctite in that spot and I would also not use an SS bolt if you can't find the original and have to make one out of something out there.

Good luck.

[n3303j]

Part Number 12 31 8 002 348 (BMW) is a direct interchange for the Moto Guzzi bolt.

Originals were finished in black oxide. Current one on Max BMW site shows a gold irridite finish. Same 10.9 tensile strength.

[Antietam Classic Cycle]

Never had one break, but then I never use it to crank the engine over with the spark plugs in. <shrug> Once again, Loops have the superior design... 

[Groover]

Both plugs out in my case, but I do recall turning the engine a little faster that maybe I should have. I remember making engine revving sounds when I was doing this, and what really did it was when the screeching tire sound kicked-in...that's when the bolt broke. I also stopped doing that when I work on stuff - bad habit 

[canuck750]

I had both plugs out at the time I was rotating the crank with an Alan Key socket.

I have a single plate Ram clutch, not timing marks, I was verifying the TDC D and S marks and then marking the static and advance lines on the RAM.

Bike was hot after along ride, I should have let it cool down before rotating the crank. When cold and with plugs out the crank turns pretty easy.

Harper's have come to my rescue again with the replacement parts I need and the advice I can trust as to removing the end of the broken rotor bolt.

Stuff happens,

So long as I can get the remains of the bolt out of the crank without drama it's another lesson learned.


Another tens years or so I may be up to junior apprentice level of a 'real' mechanic.

[nick949]

It makes me feel just a little bit better to know that things like this can happen to you too.   I was under the illusion that you were perfect - it's good to know that you too are human

That you have the courage and openness to admit your occasional mistakes just makes the work you do even more impressive.    If I were in the market for the perfect bike, I'd be looking your way (or Charlie's).

Nick

[Groover]

Is the rotor already off the shaft?

[Antietam Classic Cycle]

If I were in the market for the perfect bike, I'd be looking your way (or Charlie's).

I've never built a "perfect" bike and doubt I ever will. Do I strive for perfection? Of course, but I've yet to achieve it. 

[rodekyll]

Perfection is all that's left after the mistakes have been made.  As long as there is still a mistake that can happen, you have to drive through it and turn left to find perfection.

Canuck -- bring the busted cover to the national along with the broken bolt.  I want to jb weld the bolt in the position you took the pic and install it on the trike.  I think that big ol' hole and allen head would look good there, especially since there is no alternator behind it. 

[canuck750]

Perfection is all that's left after the mistakes have been made.  As long as there is still a mistake that can happen, you have to drive through it and turn left to find perfection.

Canuck -- bring the busted cover to the national along with the broken bolt.  I want to jb weld the bolt in the position you took the pic and install it on the trike.  I think that big ol' hole and allen head would look good there, especially since there is no alternator behind it.

You got it RK, see you in Oregon.

[John A]

Perfection is the enemy of good.

[canuck750]

Is the rotor already off the shaft?

yes, the rotor spun free of the crankshaft as the rotor bolt worked itself loose, when the head of the rotor bolt broke free of the rotor cover ( looked like a chick breaking out an egg!) the bolt caught in the rough edges of the cover, this stopped the bolt from turning and the bolt then snapped, a small section is still in the crank, This all happened in seconds.

The rotor looks fine as does the stator and crank.

I just need to carefully work the snapped off end of the rotor bolt out of the crankshaft.

[Clancy]

I want to jb weld the bolt in the position you took the pic and install it on the trike.

I like it! 

[AH Fan]

You got it RK, see you in Oregon.

What are you bringing to Oregon Jim?
I will be on the Mahogany Norge with B.C tags.........

Dale

[canuck750]

What are you bringing to Oregon Jim?
I will be on the Mahogany Norge with B.C tags.........

Dale

I am hoping to bring my Eldorado, the fenders are out getting painted, been gone 5 weeks, I am begging the painter to get them done on time so I can take the cruiser to the rally. Failing that I may be brave enough to take the V7 Sport, just not sure my body can take the Sport for that long of a ride. I could always take a KLR 650 but that seems pretty lame. I will be staying at the America's Best Value Inn, plan on getting in Friday morning. Will look for you at the rally.

[rodekyll]

I am hoping to bring my Eldorado, the fenders are out getting painted, been gone 5 weeks, I am begging the painter to get them done on time so I can take the cruiser to the rally. Failing that I may be brave enough to take the V7 Sport, just not sure my body can take the Sport for that long of a ride. I could always take a KLR 650 but that seems pretty lame. I will be staying at the America's Best Value Inn, plan on getting in Friday morning. Will look for you at the rally.

Neeners on you!     I got mine back from the painter on time, although I think I got old at a faster rate by fretting over it.  The trick is to bribe the painter with smoked salmon.  Then he gets his assistant to paint it while he goes home and seduces the ol' lady with fish.   

[Chuck in Indiana]

Perfection is the enemy of good.

Striving for perfection is only good craftsmanship. Demanding it is just being unreasonable. 

[Don G]

Jim: Get yourself a set of Snap-on LH drill dits, usually makes short work of such problems. DonG

[ITSec]

Neeners on you!     I got mine back from the painter on time, although I think I got old at a faster rate by fretting over it.  The trick is to bribe the painter with smoked salmon.  Then he gets his assistant to paint it while he goes home and seduces the ol' lady with fish.   

I guess that works, if your old lady is a sea lion... 

[oldbike54]

Striving for perfection is only good craftsmanship. Demanding it is just being unreasonable. 

  :1: The difference between an OK craftsman and a great one is how they deal with a mistake . In fact that applies to just about any activity . I would tell the young kids working for me in the restaurants , "you will make mistakes , I still do . It is what you learn from them that really matters" .

 Of course mine always cost WAAAYYY more money than any mistake made by an 18 year old cook

 Dusty