Razor Dune Buggy - Upgraded Components and then fried stuff. Advice needed..

[ts2340]

I’m baaaaaaack!! Chain popped yesterday. Been running great for months (minus replacing like 4-5 tires).
Not sure what the deal is here. Bad chain? Bad sprocket?

 

[EpsilonZero]

Those teeth look destroyed. Are you running all #25 sprockets and chain?

 

[ts2340]

Those teeth look destroyed. Are you running all #25 sprockets and chain?

Thanks for the reply! I didn't change any sprockets/chains from stock..

 

[EpsilonZero]

Is the motor sprocket #25 or T8F?

 

[ts2340]

From the description it says: Sprocket: T8F-9T

https://www.amazon.com/gp/product/B07KF8M5W6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

 

[EpsilonZero]

From the description it says: Sprocket: T8F-9T

https://www.amazon.com/gp/product/B07KF8M5W6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

T8F and #25 aren't the same. I guess the softest material between the motor sprocket, jackshaft sprocket, and chain was the jackshaft sprocket. You'll need to switch to a #25 motor sprocket or a T8F jackshaft sprocket.

 

[ts2340]

T8F and #25 aren't the same. I guess the softest material between the motor sprocket, jackshaft sprocket, and chain was the jackshaft sprocket. You'll need to switch to a #25 motor sprocket or a T8F jackshaft sprocket.

Thanks for the help.. So I will need to replace that one sprocket where you said the teeth were chewed up, right? So I need to get a new jackshaft sprocket for sure, yes? What would be the best / easiest? I have to replace the jackshaft sprocket no matter what, right? So best to get a T8F jackshaft sprocket? Do I need to get a new chain as well?

Thanks again!

 

[EpsilonZero]

Thanks for the help.. So I will need to replace that one sprocket where you said the teeth were chewed up, right? So I need to get a new jackshaft sprocket for sure, yes? What would be the best / easiest? I have to replace the jackshaft sprocket no matter what, right? So best to get a T8F jackshaft sprocket? Do I need to get a new chain as well?

Thanks again!

Personally, I'd switch to #25 motor sprocket, replace the destroyed jackshaft sprocket with #25 again, and replace the chain because it is probably damaged and it is very cheap. Check to see if your bearings are shot too; my original ones tore up with much less abuse than that.

 

[ts2340]

Personally, I'd switch to #25 motor sprocket, replace the destroyed jackshaft sprocket with #25 again, and replace the chain because it is probably damaged and it is very cheap. Check to see if your bearings are shot too; my original ones tore up with much less abuse than that.

Any ideas where to get a sprocket? A google isn't providing anything..

 

[EpsilonZero]

Any ideas where to get a sprocket? A google isn't providing anything..

Yeah... it can be hard to find certain parts. That isn't one that normally receives that much wear. Maybe you can email someone at electricscooterparts.com; they carry a lot of replacement parts and perhaps it could be special ordered. You could also get a #25 plate sprocket and machine as necessary. I get a lot of sprockets from redboarchain.com. It is also possible to delete the jackshaft, but that comes with more engine load and a higher top speed if your motor can handle it. A downside there is the difficulty in finding an appropriately sized axle sprocket since the axle is some odd metric size that nothing is made for. I ended up replacing the whole axle and all rotating hardware.

 

[madprofessor]

The teeth on that jackshaft sprocket are folded over as badly as any I've ever seen that hadn't already broken some off. All the teeth should be like symmetrical little mountains that are perfectly perpendicular (90-degrees) to the sprocket center.
At 25 seconds into the video, you can see the secondary chain climbing up off of the teeth and popping back down into them, that's the awful sound you hear. Since it goes smoothly without the primary chain on, obviously there's some real drag from the primary. With the motor just sitting there loose, it's hard to say if that's due to being misaligned during the video or not. Line it up and bolt it down straight, see what happens when turning the axle then.
Here's a link to some T8F, 25H, and #35 sprockets that fit the flat-sided electric motor shafts.
Electric Motor Sprocket #35 T8F 25H 11T 9T Tooth For Gokart Scooter Quad Buggy | eBay
I can't be of much help on the other sprockets without knowing the bore sizes. When replacing the jackshaft sprocket (looks like about a 34-tooth or so), and also the secondary chain, for $9 I would go ahead and replace the motor sprocket too. And the primary chain. And the axle sprocket. Why? So that they're all the same size. Otherwise, you'll be stuck with 3 pieces (a chain and a pair of sprockets) that have to be the same type size as whatever sprocket you didn't replace. Then you should go ahead and make both chains and all 4 sprockets the same type size. I like a #35 for that, but Epsilon is one of the best electric kart guys here, and he's recommending #25.
NOTE: You'll be wanting a chain breaker that fits your chosen type size, or a universal that fits several. One thing I'd recommend on that, make sure it's the kind of breaker that has an "anvil" on the bottom side, not just open air. I have both, and the open one SUX wind!
"Anvil" example: 3720 ARC #35 Chain Break - OMBWarehouse.com
Universal "open" example: Amazon.com: Detacher Breaker Cutter Fit for #25#35#41#40#50#60 415H,428H, 520,530 Roller Chain Motorcycle Bicycle Go Kart ATV Chains Replacement (Black) : Industrial & Scientific

 

[ts2340]

Thanks for the reply and as I mentioned before somewhere in this thread.. Apologies for being clueless as this stuff is just so foreign to me..

The sprockets you linked aren't for the jackshaft one though, right? The one with all the jacked teeth? I emailed Electricscooterparts and they don't have one either so I'm hoping I'm not screwed.. I don't know how to "machine" one or anything, unfortunately..

 

[EpsilonZero]

Thanks for the reply and as I mentioned before somewhere in this thread.. Apologies for being clueless as this stuff is just so foreign to me..

The sprockets you linked aren't for the jackshaft one though, right? The one with all the jacked teeth? I emailed Electricscooterparts and they don't have one either so I'm hoping I'm not screwed.. I don't know how to "machine" one or anything, unfortunately..

The sprockets madprofessor linked are for the motor. Most of those small motor shafts are for D-Bore or DD-Bore sprockets. You'll be able to tell just by looking at the shaft or sprocket that is currently installed.

If you pull that jackshaft you will be able to check the bore on the sprocket that needs replacement. I suggest you pick up a digital caliper if you don't already have one so that you can get precise measurements on the bore; holding a ruler up to it won't do. However, I do remember that I replaced my bearings with PGN 6001-ZZ. I don't remember the configuration of the jackshaft, but if the jackshaft is one diameter throughout, the ID of any hardware mounted to it would be 12mm just like the bearings. You should be able to order a sprocket with a custom bore if the company isn't just a reseller and has a machine shop. I know that redboarchain.com has one since they quoted me to custom bore a sprocket in the past.

 

[madprofessor]

redboarchain.com

I've gotten a lot of stuff from them too, good products and service, decent prices too. Known on Ebay as redboarchainspiderpig63.

 

[ts2340]

OK guys.. I'm back.. The weather is getting nice and I'd really like to get my son's cart fixed.. I've dumped like $500 in it so really need to get it running..

So, Im at the same spot.. Since I'm pretty green to all this I haven't done anything.. Sounds like my next step is purchasing a digital caliper, removing the jack shaft and measuring the bore size of the sprocket? Sprocket 2 is the one I'm measuring? But then you guys suggested I literally replace all sprockets and both chains??

 

[EpsilonZero]

As I recall, you had a T8F motor sprocket (4) that chewed up your #25 jackshaft input sprocket (3). Both of those need to be replaced with #25 sprockets unless you do a jackshaft delete and run straight from the motor sprocket to the axle sprocket. Razor likes to use essentially proprietary shaft diameters, so you may have trouble finding appropriately sized hardware. You can get sprocket blanks and have them machined if need be, but the motor sprocket is available off the shelf. The motor to jackshaft (4->2) chain should be replaced.

 

[ts2340]

As I recall, you had a T8F motor sprocket (4) that chewed up your #25 jackshaft input sprocket (3). Both of those need to be replaced with #25 sprockets unless you do a jackshaft delete and run straight from the motor sprocket to the axle sprocket. Razor likes to use essentially proprietary shaft diameters, so you may have trouble finding appropriately sized hardware. You can get sprocket blanks and have them machined if need be, but the motor sprocket is available off the shelf. The motor to jackshaft (4->2) chain should be replaced.

Thanks for the reply! IT's actually the sprocket labeled 2 in the picture that got chewed up.. So I can eliminate the 2 and 3 sprockets and just go 4 to 1?

 

[EpsilonZero]

Thanks for the reply! IT's actually the sprocket labeled 2 in the picture that got chewed up.. So I can eliminate the 2 and 3 sprockets and just go 4 to 1?

Yes, it is possible to eliminate the jackshaft by going from 4 to 1, but your top speed will be drastically increased without a much larger axle sprocket. I don't remember if the tensioner has enough articulation to be retained or if you will have to remove it.