Coolster 125cc 3125B

Dedbolt · 06-29-2019, 02:09 PM

Just bought my 11yo a 2018 3125B brand new Coolster ATV from Powersportsmax.com. This is my second purchase from them. No issues at all. This ATV was delivered in 3 days!! Was not expecting that...had to take a half day off work to be here for it.

Anyhoo...My older boy and I put it together and noticed a few things with it. The front brake lever was angled way up, almost vertical, on the bars. Adjusted it and the allen head bolt stripped out the cheap pot metal. Fixed that with a new bolt and nut, not a big deal. my other boy went to ride around the block to test it out and get the shipping oil warm so it was easier to drain. Put good oil in it and ran it around a little more. Went to the take keys out of it so the extra key didn't get lost and there were no keys. Half of the lock cylinder fell apart and is laying somewhere in the mesa. Couldn't find it but it still fires and runs. How big of an issue s this? Will it kill the battery?

Also, it doesn't have much torque off the line. Got stuck in a rut when my boy stopped at a crossroad. Was looking to re-gear it. Haven't looked at what tooth count it has but by other posts was thinking a 13t? Also, how does the CDI work? Was thinking about swapping that out out to increase the speed lost from the re-gear. Looks to be a cheap upgrade. Want to gain a little bit on the ATV. Seems to need a little help. Also got a Mikuni clone if I need it.

Sorry, this ended up a lot longer than I anticipated lol

FLASHLIGHTBOY · 07-01-2019, 03:02 PM

call the dealership for the key... and the power complaint... I do not know how much power you expect... but t hey usually go ok... stock.... the cdi will not really do much for you.... check it all over … adjust the chain properly... and ride..

Douglass · 07-01-2019, 04:13 PM

I have a 2017 Coolster, and a 2018 Apollo 125ATV. Both were automatic, and starting from stop can be a struggle depending on the rider weight. On the Coolster I just installed the 3 speed, and that helped the low end quite a bit, but the 1st gear is very short. I am now just about ready to do a 3 speed engine swap in the Apollo.

I think you should be able to install a 12T front sprocket. You will need to use Allen head bolts, and will need to grind down the keeper, and the allen head bolts to clear the chain. Dropping or adding one tooth on the front sprocket is the same as adding or removing 4 teeth in the rear. You will loose some top end speed.

Douglass

dirtbkr188 · 07-01-2019, 07:51 PM

I believe the actual ratio for the sprockets is 1 tooth change in either direction on the front sprocket is equal to 2.3 teeth on the rear sprocket. Below is a chart for reference

Dedbolt · 07-02-2019, 10:01 AM

I'm going to call the dealer for the key/ignition assembly. Not a big deal though. Just annoying. Haven't been able to ride much the last few days. Gonna wait a bit on the front gear. see how it does with my boy after he gets a chance to really ride it.

Al · 07-02-2019, 11:36 AM

I went from a 14 tooth to a 12 tooth. Big difference. I also bought a performance CDI,. I think there is a everywhere. For the ten dollars it cost me......my 125 will not start with the performance CDI unless the engine is warm. I think the timing is to advanced. Fyi

Dedbolt · 07-02-2019, 09:21 PM

Looking at parts diagrams for the other Coolster 125cc ATV, can't find the 3125B, it looks like its a 14T front sprocket. I'm thinking a change would be good for the hills and stuff here in the desert. I put a warranty claim for the ignition cylinder. Not an expensive part but why should I pay for someone else's mistake.

Thanks Dirtbkr188 for the chart. That helps understand a little better. Couldn't see it earlier at work. Military computers block a lot.

06-29-2019, 02:09 PM	#1
Dedbolt Join Date: Jun 2019 Location: Rio Rancho, NM Posts: 25	Coolster 125cc 3125B Just bought my 11yo a 2018 3125B brand new Coolster ATV from Powersportsmax.com. This is my second purchase from them. No issues at all. This ATV was delivered in 3 days!! Was not expecting that...had to take a half day off work to be here for it. Anyhoo...My older boy and I put it together and noticed a few things with it. The front brake lever was angled way up, almost vertical, on the bars. Adjusted it and the allen head bolt stripped out the cheap pot metal. Fixed that with a new bolt and nut, not a big deal. my other boy went to ride around the block to test it out and get the shipping oil warm so it was easier to drain. Put good oil in it and ran it around a little more. Went to the take keys out of it so the extra key didn't get lost and there were no keys. Half of the lock cylinder fell apart and is laying somewhere in the mesa. Couldn't find it but it still fires and runs. How big of an issue s this? Will it kill the battery? Also, it doesn't have much torque off the line. Got stuck in a rut when my boy stopped at a crossroad. Was looking to re-gear it. Haven't looked at what tooth count it has but by other posts was thinking a 13t? Also, how does the CDI work? Was thinking about swapping that out out to increase the speed lost from the re-gear. Looks to be a cheap upgrade. Want to gain a little bit on the ATV. Seems to need a little help. Also got a Mikuni clone if I need it. Sorry, this ended up a lot longer than I anticipated lol
	0

07-01-2019, 03:02 PM	#2
FLASHLIGHTBOY Join Date: May 2009 Location: SASKATOON Posts: 1,161	warranty call the dealership for the key... and the power complaint... I do not know how much power you expect... but t hey usually go ok... stock.... the cdi will not really do much for you.... check it all over … adjust the chain properly... and ride.. __________________ DEALER FOR ZSTAR & GIO PRODUCTS, TAOTAO ABIBABA ATV ETC
	0

07-01-2019, 04:13 PM	#3
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	I have a 2017 Coolster, and a 2018 Apollo 125ATV. Both were automatic, and starting from stop can be a struggle depending on the rider weight. On the Coolster I just installed the 3 speed, and that helped the low end quite a bit, but the 1st gear is very short. I am now just about ready to do a 3 speed engine swap in the Apollo. I think you should be able to install a 12T front sprocket. You will need to use Allen head bolts, and will need to grind down the keeper, and the allen head bolts to clear the chain. Dropping or adding one tooth on the front sprocket is the same as adding or removing 4 teeth in the rear. You will loose some top end speed. Douglass
	0

07-01-2019, 07:51 PM	#4
dirtbkr188 Join Date: Aug 2009 Posts: 511	I believe the actual ratio for the sprockets is 1 tooth change in either direction on the front sprocket is equal to 2.3 teeth on the rear sprocket. Below is a chart for reference
	1

07-02-2019, 10:01 AM	#5
Dedbolt Join Date: Jun 2019 Location: Rio Rancho, NM Posts: 25	I'm going to call the dealer for the key/ignition assembly. Not a big deal though. Just annoying. Haven't been able to ride much the last few days. Gonna wait a bit on the front gear. see how it does with my boy after he gets a chance to really ride it.
	0

07-02-2019, 11:36 AM	#6
Al Join Date: Jun 2017 Posts: 73	I went from a 14 tooth to a 12 tooth. Big difference. I also bought a performance CDI,. I think there is a everywhere. For the ten dollars it cost me......my 125 will not start with the performance CDI unless the engine is warm. I think the timing is to advanced. Fyi
	1

07-02-2019, 09:21 PM	#7
Dedbolt Join Date: Jun 2019 Location: Rio Rancho, NM Posts: 25	Looking at parts diagrams for the other Coolster 125cc ATV, can't find the 3125B, it looks like its a 14T front sprocket. I'm thinking a change would be good for the hills and stuff here in the desert. I put a warranty claim for the ignition cylinder. Not an expensive part but why should I pay for someone else's mistake. Thanks Dirtbkr188 for the chart. That helps understand a little better. Couldn't see it earlier at work. Military computers block a lot.
	1