Help with coleman mini

Lizardking

Well-Known Member
#1
Hello to all. New guy to mini bike and kart world. Just picked up this Coleman for $200 for my son;) and would like to know what can be done to make it run slower for my son since it's his first motor bike. Besides downgrading engine what else can be done? Maybe different clutch? It's currently stock with the 6.5 hp. I've tried the speed screw but didn't help enough. Any help would be appreciated.
 

Attachments

#2
Hey Lizardking...welcome to the Oldminibikes.com forum.

Nice buy at that price.

I would not downgrade the engine, as it's needed to sufficiently pull that frame.

There are ways to limit the top end...and someone with experience doing so can provide more information.

Y'all what does he need to do to make this happen ?
 
#3
One many of these engines there is a "Throttle-stop screw" that prevents the throttle from opening up fully. you screw it in to reduce max engine speed. It may have a coil spring around it.
you should be able to get to it to either side of the throttle cable.
If not, you can drill a hole in the throttle control plate and install one.
Screw next to red circle:
https://www.bmikarts.com/Predator-212cc-Throttle-Linkage-Kit-Instructions
 

Sooner79

Active Member
#4
One many of these engines there is a "Throttle-stop screw" that prevents the throttle from opening up fully. you screw it in to reduce max engine speed. It may have a coil spring around it.
you should be able to get to it to either side of the throttle cable.
If not, you can drill a hole in the throttle control plate and install one.
Screw next to red circle:
https://www.bmikarts.com/Predator-212cc-Throttle-Linkage-Kit-Instructions
On the Hisun 196cc clones that Coleman uses, the throttle stop screw comes tac welded in from the factory and one of the first things people do is to cut it off using a Dremel. Check to see if it’s been cut off. You can drill it out and replace the screw (you may need to but a nut on the other side of it) and that way you can limit the throttle from opening as far as you want it to.
 

Lizardking

Well-Known Member
#6
One many of these engines there is a "Throttle-stop screw" that prevents the throttle from opening up fully. you screw it in to reduce max engine speed. It may have a coil spring around it.
you should be able to get to it to either side of the throttle cable.
If not, you can drill a hole in the throttle control plate and install one.
Screw next to red circle:
https://www.bmikarts.com/Predator-212cc-Throttle-Linkage-Kit-Instructions
I had to put a bolt on to limit the top speed because it was missing. It didn't help much since it still takes off like a bat out of hell. I'm going to try a stiffer throttle spring since it doesn't take much to get it to take off till the governor kicks in and slows it down.
 

Lizardking

Well-Known Member
#7
On the Hisun 196cc clones that Coleman uses, the throttle stop screw comes tac welded in from the factory and one of the first things people do is to cut it off using a Dremel. Check to see if it’s been cut off. You can drill it out and replace the screw (you may need to but a nut on the other side of it) and that way you can limit the throttle from opening as far as you want it to.
That was the first thing I did, had to put a bolt on since it was missing. The bolt to the clutch was also missing which lead me to believe that maybe a stiffer clutch was used. Is there a clutch that can be used that engages at lower rpms?
 

olddog

Active Member
#8
Years ago I used a cable stop on the throttle cable for this. I think I put it after the housing attachment clamp, and the stop would hit the housing and limit the amount the throttle could be opened.

Just be careful with clearances....
 

Sooner79

Active Member
#9
That was the first thing I did, had to put a bolt on since it was missing. The bolt to the clutch was also missing which lead me to believe that maybe a stiffer clutch was used. Is there a clutch that can be used that engages at lower rpms?
Not that I’m aware of. You might just try a different clutch or lubricating the one that’s on it. Others here know a lot more about clutches than I do so hopefully they will chime in.
 

Lizardking

Well-Known Member
#10
Not that I’m aware of. You might just try a different clutch or lubricating the one that’s on it. Others here know a lot more about clutches than I do so hopefully they will chime in.
Good advice on lubricating the clutch. It feels like I have to give it plenty of gas before it engages. Looking up how to lubricate clutch now.
 

Lizardking

Well-Known Member
#11
Years ago I used a cable stop on the throttle cable for this. I think I put it after the housing attachment clamp, and the stop would hit the housing and limit the amount the throttle could be opened.

Just be careful with clearances....
I did adjust the throttle limiting screw but didn't help much. Chain was dry and rusty before I oiled it up. Clutch is next and adding a stiffer throttle return spring.
 

SAS289

Well-Known Member
#12
I think your best option is to restrict the throttle travel like others have said. And even if you do limit throttle travel the clutch engagement RPM and power delivery may feel the same. The top speed should be lower. Oiling the clutch will not change engagement RPM.

If you can't get less power/RPM with the throttle screw you may have to add something near the return spring. Problem is that too little throttle and the clutch will never engage to get the bike going or just slipping in between engagement and not engaging. You can add a spring like you see in the picture. I added this spring because I chopped off too much of the original spring. It was binding. It does make the throttle slightly tighter.

Your problem is not an easy one. Most people want to go faster not often thinking about how to make these bikes slower.
20170703_182437.jpg
 
Last edited:

old shed finds

Well-Known Member
#13
I really think. Make sure brake works perfect. Make sure kill switch is perfect. Train you boy..
These are a stock 25mph bike when new.
My dad put me on a 1976 Yamaha MX175 at 10 yrs old..Helmet and pads It will be fine..
 

Lizardking

Well-Known Member
#14
I think your best option is to restrict the throttle travel like others have said. And even if you do limit throttle travel the clutch engagement RPM and power delivery may feel the same. The top speed should be lower. Oiling the clutch will not change engagement RPM.

If you can't get less power/RPM with the throttle screw you may have to add something near the return spring. Problem is that too little throttle and the clutch will never engage to get the bike going or just slipping in between engagement and not engaging. You can add a spring like you see in the picture. I added this spring because I chopped off too much of the original spring. It was binding. It does make the throttle slightly tighter.

Your problem is not an easy one. Most people want to go faster not often thinking about how to make these bikes slower.
View attachment 263999
That's the spring I'm going to put. I have a few springs I can try. I'm thinking it's binding at the stock throttle spring too. That should help the speed limit screw do its job better. I'm also going to spray some lubricant on the throttle cable from the handle bars to engine. Feels sticky and not smooth.
 

Lizardking

Well-Known Member
#15
I really think. Make sure brake works perfect. Make sure kill switch is perfect. Train you boy..
These are a stock 25mph bike when new.
My dad put me on a 1976 Yamaha MX175 at 10 yrs old..Helmet and pads It will be fine..
Check off list is in hand. Kill switch checked, Brake has been adjusted along with tire pressure to suit the terrain. The pick up it has is hard till the governor flat lines it.
 
#16
Keep in mind, if this is a 212 predator, and the throttle is still sticky...in the pivot point assembly of the throttle lever on the motor, there is a 'wavy' shaped washer, put there for fixed throttle applications.

Disassemble the throttle lever pivot point... remove the 'wavy' washer...and replace it with a slick feeling washer of similar diameter as you reassemble...and your throttle response, and return smooth right out.
 

Sooner79

Active Member
#17
Keep in mind, if this is a 212 predator, and the throttle is still sticky...in the pivot point assembly of the throttle lever on the motor, there is a 'wavy' shaped washer, put there for fixed throttle applications.

Disassemble the throttle lever pivot point... remove the 'wavy' washer...and replace it with a slick feeling washer of similar diameter as you reassemble...and your throttle response, and return smooth right out.
He said it’s the stock Hisun 6.5 in his first post.
 
#19
I know it's not a predator, but they are both clone engines...if it's still sticky...I'd be willing to bet that pivot point shown in your picture for throttle lever has a wavy washer sandwiched in there for fixed throttle applications.
 
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