Differential rear on go cart
- Thread starter Ltcjc
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Ebrownie
Member
It seems like you must have another issue besides gearing. My kart has a predator 212 w/ 18” tires and 6:1 gearing with a 30 series, just like that. It accelerates really good and has no issues climbing. Sounds like either something is wrong with your axle setup, or something is wrong with your clutch. Are you sure you have the correct belt? And your primary and secondary are functioning correctly? Does the engine rev up when you try to drive it or does it bog down a little.
Ltcjc
New member
TC and belt are clean, the engine is responsive but trying to accelerate the rpm's increase with the pedal push, but other than an initial rolling, the cart goes nowhere. I was thinking it may be an issue with the differential. I understand the concept of the differential, but I can't find anything on line on how to trouble shoot if it is the differential. Any thoughts? Thanks.
Kartorbust
Inmate #627
If you have room to add a jackshaft for changing the gear ratio I would start there. Maybe have the existing sprocket run to a 15 with a 10 output to the sprocket on the axle.
Denny
Canned Monster
No Alex, I did not lead lead him astray one bit. I just gave him the facts as I have seen and rode in person. I think with those tires it needs a 8hp or larger with a 40 series CVT. How is that leading someone astray? Everyone is far too quick around here to say 212 and 30 when in reality bigger would be better.
Denny
Denny
Kartorbust
Inmate #627
They already have the 212. Buying another engine is going to be an added expense. $230 for the 301 or whatever other engine around the 8hp range, a 40 series runs about $169+belt, jackshaft, sprocket, maybe alignment backing plate, so already in the $550 range, then needing an engine plate (small block/big block). $50 for an extra jackshaft with sprockets, chain, bearings (pillow block).
hm 6:1 on 18" should work to roundabout 420 lbs of weight (kart+passenger)
So by now I'm fairly convinced you have a belt issue.
Most likely incorrect belt.
(I fear the 699 story continues..)
Please post a few pics of the TC (at least one of which showing the belt prints)
And a rear view to see the alignment.
One more kart total to get a good overall impression helps as well,
'sid
So by now I'm fairly convinced you have a belt issue.
Most likely incorrect belt.
(I fear the 699 story continues..)
Please post a few pics of the TC (at least one of which showing the belt prints)
And a rear view to see the alignment.
One more kart total to get a good overall impression helps as well,
'sid
Functional Artist
Well-known member
Yup, I agree. 
You lowered the gear ratio, as suggested
...so, it should go now.
FYI
Here is an "old school" video explaining differentials
https://www.youtube.com/watch?v=yYAw79386WI
Please post lots of pics, for further assistance.
You lowered the gear ratio, as suggested
...so, it should go now.
FYI
Here is an "old school" video explaining differentials
https://www.youtube.com/watch?v=yYAw79386WI
Please post lots of pics, for further assistance.
Ltcjc
New member
Where in the world did you find this film? Great presentation. Still have to work on the gearing I think. I'll let you all know how it pans out. Thanks
Kartorbust
Inmate #627
It's a video someone uploaded on YouTube. No idea how anyone finds archival footage from decades ago.
jeffmorris1956
New member
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I have watched most of the films. Very interesting. There is one film about crash testing using dummies in 1960.
Ltcjc
New member
Here's another "Clue", the driver belt is a Manco #5959, should I try another Mfg.' s belt to see if the belt's the issue?
"So by now I'm fairly convinced you have a belt issue.So by now I'm fairly convinced you have a belt issue.
Most likely incorrect belt.
(I fear the 699 story continues..)" Have no idea what the 699 story is.......... Thanks
"So by now I'm fairly convinced you have a belt issue.So by now I'm fairly convinced you have a belt issue.
Most likely incorrect belt.
(I fear the 699 story continues..)" Have no idea what the 699 story is.......... Thanks
chinese belts are often labeleld as 699... and that number is orignally for a totally different type ot CVT belt (yes CVT for gy6 engines too be precise)
seveal users bought cheap gy6 belts (because cheap and CVT)
several chinese companies put the 699 numbers on correct belts
(of mediocre to low quality unfortunately)
So if the belt carries a 699 number somewhere.. chances are it's the wrong size, shape or length,
OR just of a subpar quality.
That's the summary of the 699 story
if you have a Manco kart the 5959 belt is indeed the correct one,
if you however run a TavKit, it is the WRONG belt.
unfortunately not too many know that the TavKit belt (203589A) is actually a bit shorter than the 5959
and worse.. some put both numbers on the belt not knowing or caring about the slight difference.
So measure the outer circumference of the belt.. 5959 should be 27.4"
and the correct size is 27 1/32"
So yeah your belt's too long for your TavKit.
'sid
seveal users bought cheap gy6 belts (because cheap and CVT)
several chinese companies put the 699 numbers on correct belts
(of mediocre to low quality unfortunately)
So if the belt carries a 699 number somewhere.. chances are it's the wrong size, shape or length,
OR just of a subpar quality.
That's the summary of the 699 story
if you have a Manco kart the 5959 belt is indeed the correct one,
if you however run a TavKit, it is the WRONG belt.
unfortunately not too many know that the TavKit belt (203589A) is actually a bit shorter than the 5959
and worse.. some put both numbers on the belt not knowing or caring about the slight difference.
So measure the outer circumference of the belt.. 5959 should be 27.4"
and the correct size is 27 1/32"
So yeah your belt's too long for your TavKit.
'sid
Ltcjc
New member
Thanks for your input. I've ordered a correct size belt (27 1/32") so I'll test it out and update the thread.
J.S.@SMS
Road Hazard
You don't need a 40 series or a bigger engine. My streaker has 22x11-8 tires in back, 16x7.50-8 tires in front and is the heaviest go kart that I own. I have a predator 212, a 30 series with w 7" driven (not the 6"), a 9t on the torque converter, and a 60 toth axle sprocket. It has plenty of acceleration, and reaches about 35 at 3800 rpm. I have about 30 hours of low speed trail riding on it and the belt is fine.
Ltcjc
New member
Thanks, I'm still a novice at this. Can I swap out the 6" driven and just replace it with a 7"? I'll order a 9 tooth sprocket (I have a 60 tooth axle sprocket) and just install and see what happens?
J.S.@SMS
Road Hazard
The 7" will swap on in place of a 6", you'll just need a bigger belt. If you're running a tav kit use the 203591 belt. Mine does like to vibrate the kart around engagement, but I think that's from the engine.
newcart
New member
can i ask what differntial is in it and can I fit one in my yerfdog 3203?
Ltcjc
New member
Couldn't tell you the diff size, make or anything else, as there doesn't seem to be any accessible info on the unit itself. Update: I removed the TC, rechecked the install, put smaller tires on the rear (used golf cart tires and rims), put it all back together and it ran fine?!! The Predator 212 with the TC 30 series (10 tooth gear), 60 tooth axle drive gear pull along fine. I'm trying to upload a video, but other than adjusting the dual rear disc braked, I haven't done any other mods to the cart........Beginner's luck?? Don't know. But thanks to all who contributed to my thread.
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