Chain problems, ALWAYS chain problems

[lazar26]

Hey guys I’ve been having issues with my chain ever since the installation of mag wheels. I bought a frame on a New Years sale for a good price, finally got it all together just the other day to have so many issues with the chain. I think that one is mostly fixed but I feel some alignment issues.. pic of the bike below

Now my biggest problem has arisen again on my Kent bike, which mag wheels came in yesterday for. I kept blowing through rims with my YD100 so I just decided to get some decent wheels. Problem is I can’t get this chain right. I also again feel this is an alignment issue but I’ve disassembled and reassembled the chain and sprocket too many times to count today to get the same results. Even tried a new chain, which gave more problems as I couldn’t get it tight enough, or it was too tight.. waiting for half links.

I found the chain tightens and loosens as it turns. I have a video but it seems I can’t post it. Pics of the chain below. When I rode it, it felt like the thing was super chugging at low speeds. Like it kept jolting forward with every rotation of the piston. Very bumpy ride. Felt as if the bike was going to fall apart. It got better as I went faster but it just didn’t feel safe. Any ideas? It sounds like it’s binding near the engine sometimes.. but again it tighten and loosens depending on the rotation.

 

[CrazyDan]

Either the engine output or wheel sprocket isn't mounted concentrically.

 

[lazar26]

I’m trying a new sprocket tomorrow, I’ll try rebolting the motor up as well and try to center it.

 

[CrazyDan]

It looks like you spaced the sprocket out with floating bolts. Are they bent at all? It's better to use spacers of some sort that can take the torsional forces. Those bolts alone can't handle much side load with that gap. Pretty sure @bike4life can give us the maths on deflection for that grade bolt with that distance unsupported.
You need something called a tophat adapter. Make sure you get the right width. Lets you install a disk brake too.

 

[lazar26]

I didn’t add anything to this sprocket yet, this is how it came. I do not believe there’s anything with spacers, it’s just the M5 x 25mm bolt going through nothing more. I’m thinking actually looking at it my engine is a tad off center, a fraction to the left more than the right. Perhaps that’s causing the small jump.

I did however use some spacer bolts on the axle, stretched the rear forks maybe a few extra mm but that was about it! It seems to work okay as is that way and that shouldn’t conflict with the sprocket?

 

[CrazyDan]

If a sprocket is mounted out of concentricity then it will do the lurching you describe. Walk the bike forward and see if the chain goes "loose tight loose tight". If it does, then on of the 2 sprockets on the chain run aren't mounted concentrically.

 

[lazar26]

Thank you!! That’s my goal for tomorrow. I’ll take off all the bolts and make sure it’s centered much better. I do know it’s doing the loosening and tightening as I walk it, so it must be something to do with that.. perhaps they sent me a faulty sprocket? Hope to god it’s not the $100 wheel lol. Thanks for your help!

 

[CrazyDan]

I bet the bolts are bent. Bolts are meant to clamp 2 objects so hard together that side load against them is canceled by the objects' friction from rubbing each other. They are not meant to take side load solo.

 

[Chainlube]

Hey guys I’ve been having issues with my chain ever since the installation of mag wheels. I bought a frame on a New Years sale for a good price, finally got it all together just the other day to have so many issues with the chain. I think that one is mostly fixed but I feel some alignment issues.. pic of the bike below

Now my biggest problem has arisen again on my Kent bike, which mag wheels came in yesterday for. I kept blowing through rims with my YD100 so I just decided to get some decent wheels. Problem is I can’t get this chain right. I also again feel this is an alignment issue but I’ve disassembled and reassembled the chain and sprocket too many times to count today to get the same results. Even tried a new chain, which gave more problems as I couldn’t get it tight enough, or it was too tight.. waiting for half links.

I found the chain tightens and loosens as it turns. I have a video but it seems I can’t post it. Pics of the chain below. When I rode it, it felt like the thing was super chugging at low speeds. Like it kept jolting forward with every rotation of the piston. Very bumpy ride. Felt as if the bike was going to fall apart. It got better as I went faster but it just didn’t feel safe. Any ideas? It sounds like it’s binding near the engine sometimes.. but again it tighten and loosens depending on the rotation.

In pic #6 the sprocket isn't mounted tight to the wheel, you better address that very soon before you damage your wheel.

 

[CrazyDan]

In pic #6 the sprocket isn't mounted tight to the wheel, you better address that very soon before you damage your wheel.

It appears to be nutted against the hub, but not too sure on that. Might just have nuts backing the sprocket and only bottomed out in the hub... I'm hoping he didn't oval out his bolt holes, but I don't have my fingers crossed.
Edit: I guarantee bent bolts minimum.