Scary thing happened yesterday

[pidjones]

I rode the Hunley ~20 miles in to a car/bike show yesterday. Good turn-out and finally some bikes there! Time Warp Vintage Motorcycle Club showed up with 11 bikes plus there were about five others. Happily the show let out around 3 pm so we could beat the UT football traffic. On my way home the road funnels to one lane ineach direction with barriers and pavement grooved haphazardly. I've been through this before and stay on smooth until last thing, slow, then cross at as steep an angle as I can to keep it from grabbing a tire. No traffic behind me thankfully because I dropped 4 to 3 while gently on both brakes, ket out the clutch, and locked up (at about 40 mph!) Pulled clutch quick enough to keep from dumping it, crossed over the grooving, noticed the engine stopped. Since I was still clutched, I shifted down to neutral and pressed the start button - it started right up! I'm now coasting on the right edge of now 4 lane with no traffic. Let it coast down to ~10 mph, put it in 2nd, let out the clutch, all Ok. Accelerated on up to 50 mph (that area's limit) shifting @~3k rpm to 4th finally. Rode the ~15 miles remaining with very high glute tension and care in shifting.

Ok, what could have caused it? Whatever it was locked the engine, but allowed me to clutch, downshift, and restart. I'll be draining oil this week to check for metal. Bet I left 10' of rear tire rubber before getting the clutch back in, very lucky to have kept it straight and not high-sided.

 

[joedrum]

Hmmmm ...on hooch I have to be very careful on down shifting to the point I pretty much don’t do it ...truth is I can just back off the rpm and sometimes it will skid the tire ...after breaking the belt recently...I’d say this event for you you a good reason to change the belts ..with me now it’s screw down shifting as general rule ....

 

[pidjones]

Belts changed just a few years ago. I'm afraid it somehow got in two gears at once.

 

[joedrum]

Could be that and that took all the pressure

 

[Omega Man]

Not saying you may have, but it always seemed to me that my lazy shifting/braking/riding caused this stuff to happen to me. Glad you are okay!

~O~

 

[kerryb]

Kudos on keeping it upright, glad you're ok. Sorry I haven't a clue as to what could cause a lockup.

 

[pidjones]

Kudos on keeping it upright, glad you're ok. Sorry I haven't a clue as to what could cause a lockup.

I credit my mud-slow reaction time in not high siding. Must have finally clutched when it straightened up.

 

[GTC@MSAC]

pidjones » 15 Sep 2019, 20:00[/url]":2f55yptp]

Kudos on keeping it upright, glad you're ok. Sorry I haven't a clue as to what could cause a lockup.

I credit my mud-slow reaction time in not high siding. Must have finally clutched when it straightened up.

No worries, I've done it myself on various other bikes in the past. Havn't dumped one on account of that yet, but it always seemed to surprise me when it happened, lol!

 

[desertrefugee]

My guess is that you dropped two, not one - And the pavement was likely slick as owl snot. Like Joe, I rarely use engine braking on cars or motorcycles. (Trucks are a slightly different story). It’s just not necessary on unloaded vehicles. We have brakes for a reason.

 

[GTC@MSAC]

I not-so-infrequently up-2 on my 67 dream and my GL1100. Did it twice today on the 1100. I sometimes mis-shift and end up in between gears, and don't know which ones, so I upshift to find out. Better to lug in a higher gear than to skid in a lower one!

 

[dan filipi]

It’s easy to over-relax on an oldwing. I’ve bumped the kill switch a few times. You find out real quick just how much forward push the engine is creating lol. And it seems like eternity before reserve kicks in after main has run out.

 

[GTC@MSAC]

dan filipi » 15 Sep 2019, 21:00[/url]"1ofz7nd]
It’s easy to over-relax on an oldwing. I’ve bumped the kill switch a few times. You find out real quick just how much forward push the engine is creating lol. And it seems like eternity before reserve kicks in after main has run out.

Lol, I haven't bumped the kill switch yet. But today I kept staring at the gas gauge, myself. I almost wish it didn't have one, lol!

 

[DaveKamp]

Okay, so I'm thinking through this logically (sorry, bad habit)...

Rear tire locked up... but recovered upon pulling in the clutch...

The clutch disengages the engine primary drive from the transmission input... that means, with the clutch disengaged, the rear wheel, final drive, driveshaft, u-joint, and transmission shafts are all turning.

That being the case, this could not be entirely attributed as a 'transmission' problem... if it were (i.e., two gears' shift dogs engaged simultaniously), then pulling in the clutch would have made NO difference... because it's just disconnecting the engine.

SO... from the clutch forward, we have primary drive, alternator drive, water pump, camshafts, crank, pistons, and oil pump... and of course, half the clutch... anything else?? it would have to be somewhere in that selection.

My other thought, is that just because the timing belts aren't new, that doesn't mean they're absolved of possibility of problems... or even... getting a tooth chunk, or some kind of debris stuck in there... enough to stop the engine. I would hope that it didn't jump just enough to crash a valve, and then somehow get bumped 'back' in place... while it's possible, I don't think it very likely that it'd jump, crash, then return to normal without showing some very ghastly suggestion of the event.

Rear brake... something getting stuck in it, or mebbie a chunk of something wedged between tire and something else, and yanking the clutch provided just enough more push to eject whatever the debris was? Check the tire, and inside fender, swingarm, etc., for signs of a struggle...

 

[joedrum]

Well I’m at the belief that ..the motor itself is all it takes to skid the tire ...it happens on my bike all the time even when there is no gear changing going on ...most just don’t realize how much potential these motors have cause of the lazy stock carbs ....witch this means nothing on down shifts ...I’m sure my bike and it’s modified motor makes this condition worse ...even low rpm back off and no gear change can cause the tire to bark ...this is very yeng yang on the belts ...and I’m thinking the reason of my recent belt breaking ....and I think all oldwing riders should not down shift there bikes that much ..making the belt work completely in the opposite load stress ...it’s not a chain and can not take the same load as a chain can ...just my opinion ..but that’s what I think as it applies to my bike and how I treat it now ....the belts are the weakest link ...

 

[pidjones]

Well, compression checked this morning the same as before - 20 psi lower on the left bank than the right (I know that's out of spec). This has been a mistery on this engine all along as the left bank appeared visibly Ok but the right had surface rust that had to be shaved off with razor blades. Still, left bank is 150 each. I've also been chasing #2 fouling, so if the headers for the '79 get in today and I can get them and the mufflers on it, I'll move the '79 out of the way (presently with the rear wheel off so mufflers and headers can go on) and pull the Hunley carbs. I'll also check the Hunley left belt (again) timing.

 

[skiri251]

That's scary..
Sudden engine stop while riding (caused by ignition) didn't cause a lockup like that for me.
I was doing 60MPH on a freeway.
Must be something mechanical.

 

[GTC@MSAC]

I only ever had one motor actually seize and skid the wheel. It was with my 67 305 Dream, and the circumstances were as follows: A) I was using Castrol 20W50 per the Honda Dealer's recommendation (bad idea) instead of the specified 10W40. B) I was driving 60-60mph for 1/2 hr steady in 30 degree (fahrenheit) weather. I shifted down to 3rd at 40 mph while slowing for a stoplight, and upon slowing to about 35, the motor stuck and I began a rear-wheel skid. I pulled in the clutch and stopped the skid, and went back to 4th gear. When I re-engaged the clutch, the stuck piston popped free. Afterward it ran the remainder to my apartment in Williamsburg, but I could hear the piston slapping.