Chain broke!

reikiman's picture

I wanted to ride the Lectra over to the EAA meeting... y'know, show it off, etc. ...but... On my way over the chain broke.

I've had a couple instances where I go to take off and the chain slips off the sprocket and there's no power. It's very surprising when that happens 'cause I'm accustomed to this bike having lots of get up and go power, and when this happens it's zero. It's happened twice, the last time two days ago on my way to work.

This time I'm riding down El Camino Real in Palo Alto and suddenly have no power and pull to the side of the road. Find the chain has slipped off, so that makes the third time it had happened. I put the chain back on and take off again. Immediately again there's a sound and then no power and I pull off to the side of the road. And see the ends of the chain dangling. Soooo...

I hoofed it on to the meeting so I could hear the presentation. Also I knew 'Alias' would be there and hopefully she would be kind and generous and help me haul it home after the meeting. BTW she has some interesting pictures that I hope will get posted. Anyway we ended up taking the bike to a Honda motorcycle repair shop, and the guy says they have a policy of not working on any alternative anything motorcycle. He did take a look though and asked "is that a bicycle chain"? It's a lot smaller than a normal motorcycle chain. Hooboy. But I also took it to two bicycle shops and they don't carry anything that large, which is what I thought, that the chain is larger than bicycle chain.

The chain has '41' stamped in the side. I recall vaguely that bicycle chain is #35...? So is this #41 chain? I'll have to ask Lawrence if he remembers.

In other news I have bought a 60v charger, the one carried by MonsterScooterParts.com. This should make it a little easier to do opportunity charging on the road. This weekend I plan to redo the pack wiring - install rubber booties and install a terminal block for connecting accessories such as bank charging and paktrakr and batteq (which should be arriving wednesday).

before comments

Comments

reikiman's picture

The links are 1/2 inch from pin-pin and the pins are 1/2 inch long.

reikiman's picture

Okay, McMaster says this is ANSI #41 chain. The measurements they give are 'Pitch 1/2 inch', roller diameter .306 inches, roller width 1/4 inch.

Hmm, it also says it's rated "Working load range" of 100-499 lbs, and this sounds a bit low for this motorcycle. The acceleration is real strong so I can imagine the chain might see more than 500 lbs force but I have no idea how to calculate that.

we ended up taking the bike to a Honda motorcycle repair shop, and the guy says they have a policy of not working on any alternative anything motorcycle."

I truly believe the reason of this is for liability for their company, or any company you go to to have something worked on that they are not used to working on, even if it looks the slightest bit of difference.
I always find that you can get away with talking to shops by not telling them certain things,
and if they do not catch on that is :) they will work on it. Then again you have to be careful of that as well!
You would be taking a big issue on your hands if something else were to go wrong and they didn't know exactly what other circumstances they were getting into. So it's almost like taking a 50-50 chance.

davew's picture

I am way out of my depth here, but having the chain slip sounds really bad. Even if the chain were properly sized for the bike it might undergo some stresses in the slipping process that far exceed what it would see in normal use. Is there no way to tighten it up a bit?

"we must be the change we wish to see in the world"

reikiman's picture

I am way out of my depth here, but having the chain slip sounds really bad. Even if the chain were properly sized for the bike it might undergo some stresses in the slipping process that far exceed what it would see in normal use. Is there no way to tighten it up a bit?

Yeah, I'm outta my depth too with foot-lbs of torque versus the 'pounds' rating that mcmaster gives for the chain. I found a load test spec sheet for this motor and it has the following ratings:

Volts Amps Ft/Lb Torque RPM H.P Remarks
Continuous Rating 36 102 9.5 2300 4.15 Class H. Rating
One Hour Rating 36 122 11.6 2100 4.65 Class H. Rating
30 Minute Rating 35.0 166 16.6 1900 5.6 Class H. Rating
15 Minute Rating 34.5 180 18.2 1820 6.3 Class H. Rating
5 Minute Rating 34.0 232 25.0 1550 7.4 Class H. Rating
Continuous Rating 48 115 11.0 2850 6.0 Class H. Rating E—Enclosure
One Hour Rating 48 120 12.1 2780 6.4 Class H. Rating

I suspect that "foot-pounds of torque" is a different unit of measure from the "pounds" rating that the chain has. In any case at the moment of the break the motor would have been getting 60 volts at around 200 amps, a bit off the chart.

There is a way to adjust chain tightness and I had done so a month or so ago. At that time the chain sagged a bit more than I was comfortable with. I shoulda checked the tightness after the incident on thursday. The adjustment may have slipped a bit. But I was in a hurry to get to the meeting ...and...

reikiman's picture

I just got the chain fixed and am about to take it out for a spin.

The #41 chain is a standard size and I got a few master links to go with it. This kind of chain is kinda tricky to get to the right length. It's like bicycle chain in that the links are riveted together and theoretically you can push the rivet out to size the chain to the right length. However the chain tool I bought along with the chain doesn't properly work (rather, I couldn't get it to work right). What I ended up doing, under advisement from a V member, was to find the correct chain length, then using a grinder to grind away at one side of the correct link to get to the correct chain length, and then take that link apart. Voila a chain of the appropriate link. Once you've got it the right length the master link arrangement is a lot easier to do than the way on bicycle chains which I'd been doing last summer.

I had a bit of trouble getting it to be the correct amount of slack until I figured out how to adjust the rear wheel location. This rear wheel doesn't use a normal dropout arrangement unfortunately.

davew's picture

I had a bit of trouble getting it to be the correct amount of slack until I figured out how to adjust the rear wheel location. This rear wheel doesn't use a normal dropout arrangement unfortunately.

I was talking to a motorcycle buddy. He says that chains slipping is almost always a sign that the chain sprockets are misaligned. There is also the possibility that the chain is too loose, but it would have to be really, really loose.

"we must be the change we wish to see in the world"

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