Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

Hey everybody,

So the one thing that's keeping me from simply enjoying my Tomos a3/a35 build is the stupid chain popping over the rear sprocket when I ride the bike. i check the alignment and tension (2 finger trick), tighten it down and check again... go for a ride and come back to find the chain making clicks and pops... sounds like a dolphin fest.

I've bought a fresh chain, both sprockets only have about a hundred miles on them as the bike is freshly built, and once again... the alignment and tension look perfectly fine!.. I think you can see why I'm irritated.

I don't feel like I'm gonna throw a chain when riding or anything, but its enough to piss me off and make me even consider riding my Batavus instead :(

Re: Can't get Tomos chain to stop popping!

Have you done a proper lube job on the chain ?

The only time I hear what you describe is when the chain has seen the best part of it's life a or when it badly needs lube .

Re: Can't get Tomos chain to stop popping!

Brad William /

That sounds so much like the wrong pitch chain, or totally destroyed wheel bearings.

Since I started using hot paraffin dip to lube chains I'd NEVER touch them with oil again. When it gets a tiny pit warm it flows and lubes. It never slings. It never attracts abrasive grit. It lasts an entire season. My chains stay much more healthy.

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

I can assure you guys the wheel bearings spin great, no play and I recently installed this set of 5-star mags on the bike with pikes powder coating and mopeds in Boston.

I mean, this chain is literally brand new installed yesterday and is a KMC made 415H made to be a direct fit for Tomos.

Re: Can't get Tomos chain to stop popping!

> Dan (high idle) Conway Wrote:

> -------------------------------------------------------

> I can assure you guys the wheel bearings spin great, no play and I

> recently installed this set of 5-star mags on the bike with pikes powder

> coating and mopeds in Boston.

>

> I mean, this chain is literally brand new installed yesterday and is a

> KMC made 415H made to be a direct fit for Tomos.

And it still needs to be lubed.

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

Even after taking it out of the bath of oil it was in when it came out of the package yesterday?

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

So out of curiousity I generously lubed the chain with lubricating oil and it lasted me about a mile before the chain started popping again!!! wth? Ive had over a dozen mopeds now, never seen a problem like this lol.

Re: Can't get Tomos chain to stop popping!

Rear sprocket loose or wrong one. Chain hitting hub?

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

Rear sprocket is tight and torqued with a fresh star hub washer, gearing is stock. Im going to try some lube that doesnt fling off in a freaking mile, maybe Im just beating around the bush though now.

Re: Can't get Tomos chain to stop popping!

Shipping oil is not chain lube. Chain lube is chain lube. Oil will be gone in a mile.

Re: Can't get Tomos chain to stop popping!

Well it's pretty hard to get lube into the real inner santum of a chain where the action really is. That chain might have been in a warehouse roasting for many years all in it's little wrapper. I would try for starters soaking it in diesel. That's an old bicycle racing method. Soak it overnight wipe off and then lube with something dry. If that fails get a new chain from some other source.

Re: Can't get Tomos chain to stop popping!

lock tite that front sprocket nut. its a pain if that pops off and tears up the threads.

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

Thanks pat, it’s actually the upgraded seal nut with a fresh bent washer and locktite, that thing is on there good.

And good point Marc,

I ordered some dry lube today, it’ll be here Tuesday. Im gonna give it a healthy dousing and soak it overnight in some chain lube oil, if that’s a good idea? (it’s just what I have around)

Re: Can't get Tomos chain to stop popping!

Thin lube. Again the old grease in there is dried out and won't let anything else in. I would soak Ina real solvent and then soak in something else.

Re: Can't get Tomos chain to stop popping!

> pat splat Wrote:

> -------------------------------------------------------

> lock tite that front sprocket nut. its a pain if that pops off and tears

> up the threads.

I Second this! Worse is what happened to mine.... Sprocket spun and wrecked the splines on the shaft leading to me having to split the cases to replace the main gear.

Re: Can't get Tomos chain to stop popping!

Lotsa lube flowin in here, I think we need some pictures too

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /
863EE843-2600-462A-B216-5311221B99E7.jpeg
AB2611DA-B9E0-4789-A72E-30871ABC17AB.jpeg

Re: Can't get Tomos chain to stop popping!

At least that rear tire is well oiled . ;)

Re: Can't get Tomos chain to stop popping!

Older chain - measure it for stretch - use a 12 inch and measure from pin to pin with tension on the chain. Chain is 1/2 inch pitch and if the 12 inch pin-pin measure is more than 1/16 over then time to change it out before it takes out your sprockets teeth.

You can use chain saw bar oil on chains, its made to cling to a chain in motion.

Re: Can't get Tomos chain to stop popping!

♣Slew Foot♣ /

Nope nope nope nope nope nope nope what's your problem is is your clutch Bell one way bearing went South when you decelerate they'll pop the chain off every single time if you're brought it to a shop that would have cost you at least 20 bucks

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

Thanks for your help everyone,

I don’t believe it’s the one way bearing, This motor was freshly built for me out of brand new parts less than 100 miles ago. I should have been more specific, I can clearly hear the chain clicking on the rear sprocket. I verified this by coasting with the bike off before the clutch engaged

and could hear where the popping was coming from. No internal noises.

This morning after getting some cavities filled (ouch) I removed the chain and checked the front sprocket after removing the cover, The nut WAS indeed ever so slightly loose but being held in place by the bent washer... Phew! I popped it off, cleaned the threads with brake cleaner, spread on some high temp threadlocker, tightened, bent the washer back over 2 faces of the nut.

Then I removed the back wheel after finding a tiny bit more play in the bearings than I had liked, reset the race and lock nuts in the perfect spot, threadlocked.

As I speak the chain is marinating in bar and chain oil...

I’ll let it soak in it’s “own juices” until Amazon drops off my goodies.

Re: Can't get Tomos chain to stop popping!

Belts and suspenders. !!! Way to go. The one way bearing behaved differently when it failed for me.

Re: Can't get Tomos chain to stop popping!

When I look at the rear shot of the chain,I don't see enough clearance between the hub and chain. When the chain starts to leave the sprocket,it HAS to clear the hub.

Re: Can't get Tomos chain to stop popping!

Re: Can't get Tomos chain to stop popping!

> Mike Boyd Wrote:

> -------------------------------------------------------

> Maybe it needs this?

> https://www.treatland.tv/tomos-OEM-39-5mm-ID-sprocket-spacer-WASHER-thing-p/tomos-sprocket-washer-217158.htm

Might help!

Re: Can't get Tomos chain to stop popping!

looks like the chains been hitting on the rear lock washer tabs, u might have to double bend to get em outta the way.

Re: Can't get Tomos chain to stop popping!

How did you check the chain and sprocket alignment?

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /
0354ED8F-78A2-4F1F-9EE8-2D9046FBF377.jpeg

Definitely a spacer there. Gonna try to get back into it on my day off on the 4th.

Re: Can't get Tomos chain to stop popping!

Dan (high idle) Conway /

In the meantime i’m gonna try bringing those star washer tabs in abit, good point about the chain clearance.

Just got some nice wax based chain line tonight, i’m gonna take that chain outta the oil, let it drip, throw it on the bike and “appropriately” coat it in the good stuff.

“Dot your Ts and cross your Is”

PS-

see if you can spot the bug on my back sprocket from the last photo lol

Re: Can't get Tomos chain to stop popping!

You said you changed sprockets, so how the hell did that get in there?? What is it, a locking tab?

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