built 3203 yerf dog gearing?

Status
Not open for further replies.
F

fastion420

yerfdog 3203
Messages
62
Reaction score
0
ok,my vids are on another thread but basically I got a built predator 212 on a yerfdog 3203 with stock converter and gearing..
my kart has nice low end,,but on the top end according to my tach its revving to around 4400 at around 40mph...I think its still going but I let off around 40mph on road...
so should I drop 2 teeth down to a 8 sprocket on jackshaft?
and what diameter is stock jackshaft? 5/8 with keyway?
stock tecumesh did 27mph with same setup I gained over 13mph but I think it needs a change? opinion?
 
KartFab

KartFab

Active member
Messages
3,381
Reaction score
50
Location
Dallas, TX
8 tooth type c 40/41/420 jackshaft sprocket with 5/8" bore would be fine.

I dont know what you are trying to acheive. 40 mph is a lot for that kart since its kind of top heavy and likes to flip (i drove mine on two wheels for fun, my nephew flipped it - not for fun). If you want more torque and less speed you can always gear lower like you are saying. It is always a trade off between torque and speed.
 
Tonyzsi

Tonyzsi

Member
Messages
36
Reaction score
0
Location
Baltimore, MD
What is your goal? More top end or better low end?
Your current gearing shows that you could hit 44 mph @ 4,400 rpm's and almost another 1 mph for every 100 rps's above that. As KartFab said above that seems crazy fast to me in your kart. I have a 3203 as well and even at 27 mph my kart jumps all around when I hit a bump in the road. Have you changed the suspension at all? I want to go to hydraulic shocks in hopes they'll help dampen things out some. I'm planning to get these in the 500 lb rating: http://www.bmikarts.com/Hydraulic-Shock-Absorber-500-or-730-lbs-Load_p_3978.html

I've driven mine on 3 wheels quite a few times, but never on 2 wheels as I often have my kids in the kart with me.

I currently have a 9 tooth JS gear, but only have a stage 1 predator w/ governor. My kart has ok low end torque, but I think my TC needs cleaning/maintenance and I can't seem to get enough travel out of my throttle cable so I'm not sure I'm able to 100% full throttle.

You'll lose about 4-5 mph of top speed for each 1 tooth you lower your JS gear, but you'll gain more low end. Are you going for wheelies or donuts?
 
Tonyzsi

Tonyzsi

Member
Messages
36
Reaction score
0
Location
Baltimore, MD
These are both B Type- the gear is on one side rather than centered. I made that work for my kart using 1 or 2 small washers, but I had to grind a slot on the inside of the washer to make space for the key stock. I didn't see any C Type w/ 8 teeth.

OMB type: https://www.ombwarehouse.com/-40-41-Chain-8-Tooth-Keystock.html

Ebay: http://www.ebay.com/itm/8T-Tooth-41...ash=item2c72fd075e:g:wGEAAOSwU9xUURRV&vxp=mtr

I'm using a 9 tooth and going from 20" to 18" rear tires which has close to the same effect as going down 1 tooth on the JS gear. So in effectively have an 8 tooth. :)
 
chancer

chancer

ɔ ɥ ɐ u ɔ ǝ ɹ
Messages
9,358
Reaction score
82
Location
COMFORT, TEXAS
Yep. See the AZ in the part number? that refers to Azuza. Like Kartfab said it is an Azuza Part. So it looks like you are right on.
By the Way. While you are shopping at MFG keep this in mind. Everything ships for 6.99, wether you buy 1 tiny gear or a big box of 20 or more parts still 6.99. So try and get ALL you need on one order.:thumbsup:
 
D

draemweaver

New member
Messages
13
Reaction score
0
Location
St Louis
Thinking I put a 7 or 8 tooth on same kart. Grandson likes to do donuts and has never flipped it just spun it out. It still has good top end but he is having problems throwing chain links for some reason? I did replace shocks with stiffer ones and put a total of 6 shocks on it which made a huge difference on the handling. Put negative camber in front end by dropping down front arms to give more travel and help prevent them from being bent and modified steering for Ackerman effect.

---------- Post added at 01:00 AM ---------- Previous post was at 12:40 AM ----------

My bad I do not have same kart mine is 30034 oops.
 
F

fastion420

yerfdog 3203
Messages
62
Reaction score
0
took a lil tweaking but got the 8 tooth on!...first impression was it definitely gets out of the hole quicker...and feels like it would climb some hills.BUT not like night/day diffence,.took it down road same distance it would hit 44mph with 10tooth, and with 8 tooth I still got her to 37mph in that distance..ill get some vids tomorrow.
 

Attachments

  • 20160116_154136_resized.jpg
    20160116_154136_resized.jpg
    226.3 KB · Views: 12
2SlickNick

2SlickNick

American Minibikes @ FB
Messages
2,758
Reaction score
28
Location
Mesa, AZ.
Very nice!
Did you have to change chain length?
I have a 9t #420 sprocket on my mini bike. I will probably drop to 8T when I pull sidecar if I don't have to mess with chain length.
 
F

fastion420

yerfdog 3203
Messages
62
Reaction score
0
I went from a 10 tooth,so yeah I made a new chain,so that way I can swap sprockets relatively easy...I finally got the throttle to go WOT..i bet it would hit 50 with 10 tooth now that's throttle is fully engaging.
id love to see my motor on a mini bike,it would scream!

EDIT: just checked calculator...im at 5400 rpms at 41mph

---------- Post added at 08:16 PM ---------- Previous post was at 07:16 PM ----------

now all that's left is hooking up speedo,i got a new band brake to go on,then some new rear mud tires...and its officially ready to give to my daughter!,,,we will get some vids of it in mud and trails soon!
and DAD is gonna find a kart frame and or build one..and do a sick 420 predator build or maybe the 22hp v twin..
 
F

fastion420

yerfdog 3203
Messages
62
Reaction score
0
I just ordered rear tires,4 ply,with a nasty tractor V pattern 80$ a pop on amazon,should be a blast in the trails!
 
Tonyzsi

Tonyzsi

Member
Messages
36
Reaction score
0
Location
Baltimore, MD
Nice! I just ordered and installed Kenda Scorpion K290's, 18x9.5 and they were only $85 for the pair delivered. They hooked up really good in the snow we just got here in Baltimore!
 
Status
Not open for further replies.
Top