Have you ever seen a clutch this burned?

[Firehawk068]

This came out of one of our Police bikes at the shop today.
It's an ST-1300PA





I swear it looks like it spent 20 hours in my Smoker! It has a nice bark on it........

If I wasn't aware that it was just removed from the bike, I would assume they lit it on fire first.
I don't know the full story of this bike, but I know it came to the shop on the flat-bed and had a write-up for "Clutch Problem".

[fj1289]

A new rider spent a lot of time at Bandimere for the Colorado State Patrol sponsored test and tunes?!  Looks like a LOT of heat - but still a lot of material left.  Make sure they drop the oil pan and clean the oil pickup thoroughly.  Many a drag bike has lost a rod after a clutch issue - the residue either clogs up the pickup screen or "balls up" and restricts the flow to one or more rods. 



Only once I've seen worse...



That was an expensive mistake!

[aviationfred]

I believe the offending officer should be redeployed to driving a cruiser and never allowed on a motorcycle again.



Fred

[JPaganel]

How do you even do this?

[Firehawk068]

How do you even do this?

I am not quite sure?

Let the bike idle for hours, and then full-throttle 5th gear starts?

[PaulG]

Maybe some miscreant dumped something through the oil filler cap while it was parked.  I remember watching an IMSA race on tv years ago.  One of the teams had a recurring slipping clutch and found that dumping Diet Pepsi into it cured the problem (but Diet Coke wouldn't work).  So what would it do to a normal clutch? Tin foil hat theory for the day.

Maybe one of the riders keeps his fingers on the clutch just enough to engage the plates slightly enough to burn it out.  Years ago (again...) my sister in law burned out two clutches in their VW Golf diesel by resting her foot on the clutch while driving.  They and the dealer couldn't figure out what was happening.  When she told me, that's what I immediately asked her, if she rested her foot on it.  "Oh really?... Uh oh, don't tell you're brother!"

[Earl Svorks]

  This brings to mind something I encountered on an ex- police Kaw 1000 acquired at auction
in a Californian city then imported to Canada that wound up in an East Van bike shop on my bench. The engine had a stripped cam bearing cap bolt hole. It was necessary that I remove
both cams. As I did so, it became apparent that  most of the bolt holes had been heli-coiled.
Equally apparent, the fact that all the inserts still had the little break off tab more or less, intact on the bottom of said insert. The bolts , the helicoils, the bolt holes, the cylinder head all beyond repair.  The road to hell is paved with good intentions,,, and helicoil inserts.
   Cheers
   Simon

[JMR]

 Helicoils are OK if they are installed correctly......they are stronger then the original aluminum bolt hole. I have installed many in SOHC CB750 cam tower bolt holes when used with high performance cams. Also case cylinder stud holes in different bike engines.

[Pat Conlon]

Yep, we used inserts, called them "case savers" on hopped up VW engines.

[fj1289]

Yep, we used inserts, called them "case savers" on hopped up VW engines.

OK, FJ's, Miata's, old school Honda choppers, and now aircooled VW's -- what other toys are you playing with Pat?

[Pat Conlon]

Hey Chris, my current project is a '55 TBird. It was my dad's so it's still considered a 1 owner car. I've got the 292 out and I'm trying to fit some stainless steel valves and hardened valve seats and guides. The solid lifter engine has 10.5 compression and the oem soft valves/seats/guides will burn using the current crop of E10 unleaded fuel. I'm tired of adding cans of Octane booster (with lead) to the gas tank.
Unfortunately Ford does not make anything for this family of Y block engines (272/292/312) so I have to use Chevy (shudder) 327 valves and have them turned down to fit the Ford head. I just converted the old 6 volt positive ground system over to 12v negative ground like the later '56/57 TBirds..

My VW, CB750, MGA, MGB, Austin Healey days are well behind me... I do love that Miata 'thou.

Cheers!

[ribbert]

Yep, we used inserts, called them "case savers" on hopped up VW engines.

Interestingly, VW used to have a widespread problem with heads coming loose (studs turning not pulling), even on standard motors. The factory supplied fix, at the owners expense, was a kit with inserts like these and new studs. The inserts were not to provide additional strength, although they did by default, it was to allow the fitting of studs with a different thread pitch, which was determined to have been the problem. I fitted a number of them and it was an expensive job as the cases needed to be stripped and sent out.


Noel

[rlucas]

Hey Chris, my current project is a '55 TBird. It was my dad's so it's still considered a 1 owner car.

Damn, Pat - you keep coming up with stuff we have in common. My Dad's on his second '55.

He had a red one when I was a kid; I always wanted it but he never would let me drive it. I got to drive the current one to a car show a couple of years ago and I found out that, apparently, humans were much shorter in 1955. My head hit the roof, I couldn't push in the clutch because my knee got jammed between the steering wheel and the door, and the performance was somewhat less than exhilarating.

Still one of the best-looking cars ever, though.

[Earl Svorks]

   Noel,
  The inserts pictured in your post appear to have a finer pitch on the outside (1.25 mm maybe) and perhaps 1.5 mm on the inside. This fits with what you said about the VW mod. Do my eyes deceive me,
or are these the same?
   I had a mill foreman who insisted that "It's a fact that fine threads are stronger". It was pointless to argue as a little authority will trump any amount of trade qualification.I don't work at that mill anymore.
   Cheers
   Simon

[Pat Conlon]

.... I had a mill foreman who insisted that "It's a fact that fine threads are stronger". It was pointless to argue as a little authority will trump any amount of trade qualification

Mechanical Engineers have figured this all out before we were born.

Size for size a fine thread is stronger than a coarse thread . This is both in tension (because of the larger stress area) and shear (because of their larger minor diameter). 2. Fine threads have also less tendency to loosen since the thread incline is smaller and hence so is the off torque.

Suggested reading:
http://www.boltscience.com/pages/faq.htm
http://www.katonet.com/article/coarsevsfine.html
http://www.eisc.com/support/coarsefine.htm
http://www.eng-tips.com/viewthread.cfm?qid=72123
http://www.hotrodders.com/forum/fine-vs-coarse-thread-177132.html