Mini quad build

[Dieselchanic]

Hey guys, I'm the newb here in case you haven't seen my intro. I've got a Chinese 4 wheeler frame that was given to me. It's stripped, and missing the swingarm, but that's ok. I'll start off with some pics of what it looked like when I drug it in the shop tonight.

I received a clutch and chain in the mail so I could mock things up just to make sure it would work before I do any work. I set the motor in and hung the chain. Can you run these clutches backwards like this? Seems I did once in the past...

I've got a bit of a chain clearance issue but that shouldn't be too big a deal. Next I pulled the shocks out. The suspension on these things is a bad joke so I'll be running solid struts in the front and making a rigid axle mount in the rear. Looks like I may have to adjust the camber too. At any rate it looks much better low like this.

I'm going to be running this carb on the Briggs once I build an intake manifold for it. Also I'll build a tank that mounts above the frame.

I've got a 10t clutch, 32t sprocket, and 16" tires. Any idea what my speed will be?

 

[Russ2251]

I've got a 10t clutch, 32t sprocket, and 16" tires. Any idea what my speed will be?

Consider a much larger driven sprocket (well over 100 teeth by my calculation), or better yet, a CVT.
Current ratio is way off the mark and will burn up clutch in no time. Won't be able to get out of it's own way.
Replacing wheels with something much smaller would also work.

 

[landuse]

Consider a much larger driven sprocket (well over 100 teeth by my calculation), or better yet, a CVT.
Current ratio is way off the mark and will burn up clutch in no time. Won't be able to get out of it's own way.
Replacing wheels with something much smaller would also work.

X 10

You are geared far too high with those sprockets. You want at least 8 or 9:1. That means a 80 or 90 tooth sprocket. Like Russ says, bigger would be better

You can run your clutch like that

 

[Russ2251]

That means a 80 or 90 tooth sprocket.

Still too small.
If #35 chain, 115 teeth would be optimal and may not be available.
CVT or re-gearing through a jack-shaft is best bet.

 

[Dieselchanic]

I'm using a 420 chain. I will probably have to get a bigger driven sprocket. The 32t is what was on the quad in its former glory.

So if I can run the clutch like that, everything lines up pretty well. I still have the clearance issue but I may just use a skateboard wheel to hold it up since that's the slack side of the chain...

 

[landuse]

Clearance will be worse when you get a larger sprocket

 

[Dieselchanic]

Clearance will be worse when you get a larger sprocket

True that. I may have to redo the frame in that area. I'm trying to get away with as little fab as possible just because of the time factor...

I figured the speed with my current setup and I come up with around 75 mph. Lol. Biggest sprocket I can find that bolts up is a 60t. It might work...

 

[landuse]

True that. I may have to redo the frame in that area. I'm trying to get away with as little fab as possible just because of the time factor...

I figured the speed with my current setup and I come up with around 75 mph. Lol. Biggest sprocket I can find that bolts up is a 60t. It might work...

With tyres the size of yours, you are not really going to be going anywhere with a 60 tooth sprocket

 

[Dieselchanic]

60 tooth calculates at 30 mph at 4000 rpm. I've ridden gokarts heavier than this that go faster than 30 on a clutch. So.... Why is this not gonna work?

 

[Dieselchanic]

Not being snarky, just curious. If it doesn't work, I can add a jackshaft and still utilize the same sprockets.

 

[landuse]

60 tooth calculates at 30 mph at 4000 rpm. I've ridden gokarts heavier than this that go faster than 30 on a clutch. So.... Why is this not gonna work?

Because your high gear ratio will cause the clutch to slip continuously an get fried pretty quick. It is like pulling off in a car that is in third gear

 

[Dieselchanic]

Ok.. So what target top speed should I plan for and what rpm can I expect from the flathead?

 

[Russ2251]

If everything is correct....expect ~18 to 22 mph with an unmodified engine.

 

[Dieselchanic]

I cut the ends off the stock shocks and welded in 5/8" solid bar to make struts. It's sits nice and low now but I need to adjust the camber.

 

[mysteryboy28]

why would you remove the suspension? crappy suspension is better than no suspension at all.

 

[bamajoe]

why would you remove the suspension? crappy suspension is better than no suspension at all.

Have you ever riden a Chinese quad like that? There's no damping whatsoever.. It's like riding on springs just bounces and is very scary...

 

[ML-TOYS]

Have you ever riden a Chinese quad like that? There's no damping whatsoever.. It's like riding on springs just bounces and is very scary...

Why not just replace with softer shocks then ?

 

[Dieselchanic]

Because it's junk. The whole frame is total junk. If it moves it wears out extremely quick. It will ride way better rigid than it would before and suspension wouldn't help that much on something this small anyway. Almost all mini bikes are rigid...

Plus, I'm just killing time and building this for amusement. If it amuses me to build a super low rigid 4 wheeler that goes 40 mph, I will.

 

[landuse]

Because it's junk. The whole frame is total junk. If it moves it wears out extremely quick. It will ride way better rigid than it would before and suspension wouldn't help that much on something this small anyway. Almost all mini bikes are rigid...

Plus, I'm just killing time and building this for amusement. If it amuses me to build a super low rigid 4 wheeler that goes 40 mph, I will.

We are just trying to give you some advice here. Whether you take it is up to you.

 

[kaymo]

i work on a lot of these mini quads and the junk suspension is better than nothing, ive run into some dead rear shocks that were all but useless but ive never had one pogo around or anything. yeah stuff wears, but only if its not tightened and aligned properly. if everything is setup right in the first place its not so bad.

after riding a bunch of rigid stuff including mini bikes, i will always go for the suspension. its fun to ride something silly every once in a while but i just cant imagine getting rid of suspension thats already there. yeesh...

i just have to disagree with "ride better"