fear of chain locking up

GoldenMotor.com

deskman

New Member
Aug 29, 2012
42
0
0
california
Hello gang!


I just finished my first build...for real this time...it runs well...i think...ive ridden it probably 2 miles or so and no real issues

I'm still breaking it in.


I bought 41 chain and attached that without a tensioner because last time i used one it killed my back tire.

I'm using a half link and a master link and i have this incredible fear that my chain will jam in the engine and lock up my tire.

the chain is pretty well fitted, not rreeeeeaaaallllly much slack...even with a half link i couldnt shorten it any more....

but the combination of a half link, then a master link immediately after sort of frightens me, especially with my chain not being really tight...

what i suppose im asking for is some assurance that my chain won't freeze up and send me flying...


here's my new bike by the way!

http://sphotos-b.xx.fbcdn.net/hphotos-snc6/244317_4563688414298_1883337078_o.jpg
 

Ted

New Member
Apr 20, 2010
208
0
0
Leavenworth Wa.
It looks like you have room to mount the tensioner away from the tire, use it, if the chain did come off at the engine is where it's going to happen and probably rip the side case off.
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
i broke 4 chains over the years. 3 of them just fell off and ended up in thd street, and the other one came off and cracked the case.

none of them did any damage to me, but it's possible, i guess.

i never run tensioners, and i don't use masterlinks or half links, either. i trim down, or add shims to the rear motor mount block to move the motor forward or backwards to take up the slack.

assurance? you're building a hi speed bicycle. there's no assurance. good luck...:)
 

deskman

New Member
Aug 29, 2012
42
0
0
california
what do you mean by trim down?

also update for anyone curious, i was riding my bike home tonight when my chain popped off the back sprocket, i then put the chain back on and it derails again, i put it back on again and the chain splits.

that stupid stupid masterlink exploded! it was dark so i never was able to recover the blasted thing. i came home, attached a new masterlink and grinded the pins down slightly hoping that itll help it not hit anything. i also opened up the clutch plate and grinded the part on the side that chain always rubs on.

i'm hoping that this will let my chain grind less...and reduce the possibility of my masterlink getting caught on something.

my half link doesn't seem to be giving my any trouble, doesn't show any signs of wear.

if my masterlink does give me more trouble i'll just have to ditch it and find someone with a chain breaker...

i did my best to test out the chain by riding around the block a few times with the engine off(didn't want to infuriate my poor neighbors)...and at 20-25ish mph it doesn't seem bad...chain seems to be running quite smoothly...

here's hoping!
 

bairdco

a guy who makes cool bikes
Aug 18, 2009
6,537
264
63
living the dream in southern california
if your chain keeps popping off, it's either too loose or not aligned right. from the picture, it looks pretty loose.

what i mean by trimming down the rear motor mount block is exactly that.

if you cut the block down 1/4", it will put your motor in a slightly different spot on the frame, closer to the rear wheel. by making a shim it'll move the engine forward (Venice Motor Bikes makes a shim kit.)

most bikes i've done, removing 1/4" from the block will add a 1/2" to the chain.

basically, you're adjusting the motor instead of adjusting the back wheel.

since you can't adjust the rear wheel because of your drop outs, it looks like you can remove the half link altogether. there should be 1/2" or less of play in the chain.

a chain breaker is a valuable tool to own. i don't run masterlinks because that's the weakest part. i've broken them on pedal-only bikes before, so i just don't bother with them.

but none of that matters if your chain's not in a straight line to begin with. it'll always walk off the sprocket.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
Nice! The best thing to do though is not use a tensioner. The tensio nshould be at 1/8 to 1/2 an inch.

That's too tight. anything tighter than a half inch risks putting too much pull on the shaft/bearing.

Of course you'd have to run a bike more than a couple hundred miles to wear anything out...

To each his own though.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
Best to just do what needs to be done for correct tension- 1/2" to 3/4".

Still not sure about all this chain stretching stuff. Of all the kits I have built a few had the chains loosen slightly after awhile, but I never had an issue with having to re-tighten the chain all the time. The chains don't actually "stretch" the rollers get worn in a bit, and the sprocket wears in and the chain loosens, but doesn't really "stretch". Just like cables don't stretch, that's a misnomer.
 

dodge dude94

New Member
Jun 8, 2012
1,017
1
0
East Texas
I had a problem for a while where I was having to tighten my chains all the time. Now that I have a bunch of miles on the same chain, I don't have to worry about it as much.

If only I could keep my pedal chain tight...
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
Sounds like you have a frame bending issue. The only time I ever saw a chain keep loosening up, was when a customer (big guy) rammed his bike through every bump and pot hole and he was actually shoving the seatpost down through the bottom of the frame.
 

Goat Herder

Gutter Rider
Apr 28, 2008
6,237
20
38
N.M.
i think a few folks get chain stretching mixed up with the idle roller settling over time? When it is set too tight and also simply starting the motor up puts tension on that idler every time. When in a sweet spot it gets to be more forgiving.

For me with everyday riding when I used a H.T motor it would loosen that idler a little every weak or so. I would just reset it and go while again. When staring the motor the roll of tension on the motor chain reverses it self.

This is why you hear stories from folks periodically saying their tensioner went into their spoke after a start up. When set up right and properly maintained these tensioners can work great.


I was pretty happy when finally coming up with my first spring design ones.
 

deskman

New Member
Aug 29, 2012
42
0
0
california
Final update... :confused:


My new tensioner is working great! I hit 29mph and am sure that I could go faster. Chain seems to be working nicely.

Now that I'm getting to higher speeds my rpm is obviously much higher... At what point should I worry about the rpm being tooooooo Hugh?
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
Final update... :confused:


My new tensioner is working great! I hit 29mph and am sure that I could go faster. Chain seems to be working nicely.

Now that I'm getting to higher speeds my rpm is obviously much higher... At what point should I worry about the rpm being tooooooo Hugh?

When it vibrates out from under you.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,837
252
63
up north now
Well, they kinda limit themselves as to max revs. Most of them vibrate so bad at higher rpm that you just don't want to rev them higher.

Ride it like you stole it!