Chains Chain jumping teeth

Discussion in 'Transmission / Drivetrain' started by Joe, Jan 12, 2012.

  1. Joe

    Joe New Member

    I'm going to attach a photo.

    Is it common for the chain to jump teeth on the engine drive sprocket? This was really aggrevating as you can imagine. Couldn't even pedal it home! Had to carry the back wheel off the ground. I was about 3/4 mile from home.:veryangry:

    I've noticed that when I release the clutch to fire the engine up, the engine pulls over about 3/8 to 1/2 inch to the left. I have the motor mounts/straps tightened down as much as possible. I'm thinking I'm going to need to fabricate better motor mounts and possibly even an additional upper motor mount.

    Attached Files:

  2. motorpsycho

    motorpsycho Active Member

    the chain doesn't appear to have jumped teeth.
    what it looks like to me is that you have a very stiff link, that has failed to bend.
    BUT, the chain looks well used and it shoudl be loose and free, unless you don't have any lube on the chain and it's dried out.
  3. Al.Fisherman

    Al.Fisherman Active Member

    Looks the same to me....I'd go with a new chain, as when that happens you have a very good chance of ruining the engine, if lucky just the cover. Oops...looking back closely at the picture you destroyed part of the case.
  4. Joe

    Joe New Member

    To me it just demonstrates the lack of quality of the original parts. This chain is basically new. Probably a total of 5 miles on it. Never ridden in the rain. I've never greased it, but it was greasy out of the package, so that's why I didn't bother. I guess that's the way it goes. If these kits were USA made, they'd be $450-500... not $150 shipped. But they'd also be 90-100% ready-to-ride after assembly. Not 40-50% like they are. Still, I'm confident that I can get my bike to a very reliable state for much less than $450-500.

    I actually broke a link on this chain when I was first trying to get the bike going. That was with the original tensioner.

    I've read threads about people swapping to a USA made #41 chain. I'll make a run back to Tractor Supply and get one.
  5. motorpsycho

    motorpsycho Active Member

    There's your problem, a new stiff chain.
    these chains are cheap, and they are poorly lubed from the factory.
    You should go through the chain., link by link, lubing and working each link back & forth to loosen them up.
    I know, it;s a new chain and you shouldn't have to do that...but it is a china made chain in a $150.00 engine kit:rolleyes7:
    both of my chains are original to my engine kits and both are about 3-4 years old, with several miles on them and i have never had a chain mess up.
    of corse, i went through the chains when they were new, link by link, lubing and working them to loosen them up before i ever put them on my bikes.
  6. Joe

    Joe New Member

    Cool man. I'll clean it and then soak it in some lube. It'll save me a few bucks. I looked at chains when I was at TSC to get the idler sprocket. #41 chain was about $16 for 10' with masterlink.

    What would you recommend? Motor oil, gear oil? I've got alot of half empty bottles in my garage. Both dino and synthetic.
  7. motorpsycho

    motorpsycho Active Member

    well, here's what i did with both chains on both of my m.b.'s.
    I went through the chains, link by link moving them back & forth with my fingers. if any links were tight, i sprayed some lube that has teflon in it between the 2 links, down into where the pins are. then, just worked it back & forth with my hands until it got free.
    it can be time comsuming if you have more than one tight link. I only had 1-2 on each one of my chains and it took longer to check each link than it did to get the stiff ones freed up.
    As far as lubing the whole chain, it's best to get whatever lube you decide to use, down in between the links where they pivot on the pins.
    I just use grease on the outer surface of my chains, (on the rollers where the chain contacts the sprockets) but on occasion i shoot some teflon lube down in between each link onto the pins, and pivot points.
    This is just my personal preferance, and honestly, ANY lube will work and be better than what comes on the chains new, as long as it gets down in between the links to lubricate the pins. I seriously think the only reason these chains come with any lube on them is just to keep them from rusting while they are boxed up waiting to be sold. I don't think that lube is good for anything other than preventing rust.
    I like to keep my bikes clean so i do not over grease the chains because extra grease / lube will fly all over the place once you start riding.
    Last edited: Jan 13, 2012
  8. Joe

    Joe New Member

    Cool. When I was a kid my dad had me service our dirtbikes and quads. I would just take the chains off, let them soak in some 30 weight motor oil, and then hang them up to drain off the excess. But I'll work through each link like you suggest while they're soaking. That should loosen it up.
  9. Big Red

    Big Red Active Member


    Moto, I've found that if you run a REAL LOOSE chain it'll do the same thing. It slaps around till it bunches up in the case. A friend busted out a case the same way. While everyone is giving good advice, I thought I'd include a mention about chain adjustment. A noob may not realize how important this is. If a chain adjuster/tensioner slips then it could also result in a bunched up chain.
    Shiney Side Up,
    Big Red.
    Last edited: Jan 13, 2012
  10. toojung2die

    toojung2die Member

    My two favorites are Prolong and Triflow, but there are dozens of other really good chain lubes. Just wipe off as much excess as you can. Too much flings off all over everything and collects more grit.

    If you find a stiff link, flex the chain back and forth sideways at the tight link, in the direction it's NOT supposed to flex. This will loosen the tight link right up. After adding or removing links with a chain breaker the link is always too tight. A little gentle sideways bend and flex will fix that.
  11. graucho

    graucho Active Member

    I'm not saying it's not a stiff link, probably is... But dealing with these P.O. cr@p engines for a few years here are a few other reasons where i have seen this before.

    The idiot manufacturers/supplies from china shipped you a #40 chain, not a #41. Some have said over the years they are the same, there not.

    Or, When you get rolling and the chain gets into a bouncing rhythm it hops/bunches the small sprocket and jams.

    Or, the chain picked up a tiny piece of debris sucked it into the sprocket and caused a jamb. Unlikely but has happened.

    Or, alignment from the rear sprocket to tensioner to the small sprocket is off slightly bunching the sprocket.

    Or, engine is mounted slightly crooked causing the chain to twist slightly causing tension on the chain pins making them stiff as they pass the sprocket, bunching the chain

    Just saying... all of these things have happened to me, but I agree its probably a stiff link. LOL
    Last edited: Jan 13, 2012
  12. Joe

    Joe New Member

    I have used a chain breaker tool on numerous links of this chain. First to get the initial length. Then again several times after I made my new tensioner. And then there was the broken link I had to remove. I spliced back in pieces that I had left over.

    I could be wrong, but I think my supplied chain is a #415. I'm not a roller chain expert, but I'd never heard of #415 chain until I bought this kit. And you're right, #40 and #41 chains are different. My friend and I learned that on his go-cart when we were 12.

    My chain tension is good... really good since I made the new tensioner. But I know I've been having problems with my chainline. I got most of it worked out. My bet is that you and the others are right and I have a stiff link(s). But the chainline would get out of alignment because the engine would torque to the sprocket drive side when I would release the lever to start the engine. This problem happened after the engine had been torqued over.

    I ordered a new rear hub and sprocket from Pirate Cycles which should be here tomorrow. I'll get those parts installed and then work my way forward to get the chainline perfect.

    Btw... the Bevis and ******** in me is still giggling about "stiff link". HA!
    Last edited: Jan 13, 2012
  13. Joe

    Joe New Member


    Alright guys... I think I'm just going to pick up a USA made #41 chain.

    Took the bike out tonight for a short cruise. Chain broke! No studder, no snapping sounds... nothing. RPM's shot up and speed dropped. That was it. It was dark but I found the chain. Because it happened so innocently, my initial thought was that the master link became loose and fell out. Nope! As you can see in the pic, the chain broke right next to the master link.

    The other photo of the link pieces are from the first time the chain broke... in the daylight so I found the pieces.

    Attached Files:

  14. wan37

    wan37 Member

    On the new chain don't make it to short and then have to add back ,because every time I have added links, that link would be tight so your better off not to add links if you don't have to.
  15. graucho

    graucho Active Member

    Ahh, the weak link. Maybe the pin was 1/4 way out and you didn't notice it. The chain tunnel is tight... maybe the pin sticking out a bit was causing it to jamb in the tunnel. Now I guess you throw out that "possessed" chain and make a trip to tractor supply for a good #41. Maybe have a Priest bless it while your at it. Ha!
  16. Al.Fisherman

    Al.Fisherman Active Member

    Problem solved :>)
  17. Big Red

    Big Red Active Member


    Joe, If your engine is still moving around, even a little bit, It could be part of the problem. Every time the engine moves (even a little bit) it throws the chain out of alighnment. To check this I grab the the top of the frame and the engine head, (wait till it cools off,) and try to make it move. If you can make it move by hand it will surely move when riding. The engine CAN NOT move AT ALL.
    Everyone is giving great advice about a tight link, but I've found a link has to be REAL,REAL, tight to jam it in the case. This is a possiblity with the POS chain that comes with the kit. If you can wiggle the links back and forth with your fingers, then it's probably not tight enough to jam. the tension and pull of the engine is A LOT more than you can do with your hands only. I get tight links all the time and I just use a punch or chain tool to loosen it, soak it in chain lube and work it back and forth a few times. Just make sure the chain pins are even on both sides when yer done.
    Just my opinion, (I have been known to be wrong at times,) But it really sounds to me like a combination of cheap chain and engine alighnment. Get a better chain and REALLY TUG on your engine to make sure it's tight. And, If you have to, get a straight edge to check engine/ rear sprocket alighnment. I mostly just eyeball it, but a straight edge would get it closer. And last, But not least, especially if you're using a rag mount, Make very sure you're not getting a back and forth or side to side movement in your rear sprocket. Back and forth will put way too much pressure on the chain. side to side will take it out of alighnment every time the sprocket goes around. It's almost impossible to get a rag mount perfect, but it has to be very, very close. At times I've spent 3 or 4 hours on a stubborn rag mount trying to get it just "good enough". As soon as you can you should go with a hub mount system if you haven't already. Good Luck.
    Shiney Side Up,
    Big Red.
  18. Joe

    Joe New Member

    Yeah, the chainline has been a problem... mainly from the engine moving. I was out of town this weekend so I didn't get to play with the bike. But the brown truck did deliver my new hub, wheel and sprocket from Pirate. That should be a big improvement! One night this week or maybe next weekend, I'm going to fabricate a top motor mount. Hopefully that should solve the problem. Probably also going to fabricate lower motor mounts too. No more clamp around the frame.

  19. Big Red

    Big Red Active Member

    Engine Mount

    Joe, I'm not sure what you have in mind for an engine mount, But whatever you do, DO NOT drill a hole in your frame. You can go with a better grade stud and nut that will allow you the extra torque needed . You can also use a U-bolt type mount on the front mount. e-bay has a dual U-bolt type that I'm thinking about for my new build. (Item #150716824212.) But at $15 I can make my own. The two U-bolt type has two points of contact that should prevent the "swivel" effect you get with most mounts. I've also seen some mounts welded directly to the frame. With a good steel frame, a couple peices of good steel,(one front, one back,) a drill press and a welder you can do a mount that Zeus couldn't move. (I hope you ARE using a steel frame.)
    Knowing you haven't got the engine tight yet tells me A LOT. I think MOST, if not all of your chain problems are from your engine/rear sprocket alighnment stemming from engine movement. A hub mount and chain upgrade is the best way to go, but it won't do much good if your engine is moving around. It will still twist the chain into catastrophic failure, even a good chain.
    Let me know when and how you finally get yer engine tight and take it for the first test ride. I think your first words after that are gonna be YAAAHOOO!!!
    Shiney Side Up,
    Big Red.
    Last edited: Jan 17, 2012
  20. Joe

    Joe New Member

    Well I got my solid motor mounts finished. I'm pretty happy with them. The engine no longer torques over. The isolaters allow for just a little movement. Put the new #41 chain on as well. Much better quality that the original chain.

    I'll post a couple pics here, but I've already posted all the pics in an album.