2017 Coolster 3125 CX-3 - Build

Douglass · 03-13-2018, 11:02 PM

We finally got to take the ATV out for its first run on Sunday. The bike was limitied to at most a 1/4 throttle for my son (5 years old), but drove very well. I decided to replace the carburator, because I could not get the idle to stay consistant. The new carburator bolted right up, and did require a little tweeking. I could use some more, but the ATV runs very good as is. I will wait until I get a little more run time to fine tune it. I did replace the generic spark plug with an Ngk plug, and that seem to be the icing on the cake. Valve adjustment was done after about an hour of light riding

As far as the build went after removing the box, there was more bolts than I expected that were not tight enough, the chain was so tight that I could barely spin the rear axle ( this would suck for someone not mechanical). The chain tensioner was not position very well in my opion, so I cut some material off the bracket so the roller would be postioned better on the chain. The right rear hub was not tightened all the way, and had come loose front the factory after the 1st test run, and none of the grease seals had grease on the lips 100% dry.

The ATV front shocks are horrible. I could at best get about 1/2" of compression, the rear shock is just ok. I have replaced the front shocks, and will replace the rear shock this weekend. The shocks made a fantastic improvement front and rear, and have adjustable lenght and height. I added a tether kill switch, and a set of 2 inch rear wheel spacers. The kill switch was wired up to the factory kill switch wires near the connector, and routed through the black wire tube to keep it looking factory. The wires were soldered, and wrapped with heat shrink tubing. The wheel spacers came with the needed lugnuts 10x1.25mm thread pitch to install onto the hub, not modifications needed.

So far I think it is a great value, but for someone who is not mechanical, it could have been a frustrating purchase. Overall I am mostly happy with the purchase, but my have purchased the TaoTao New Cheetah if I had to do it again. The three main things I noticed between the two is the Cheetah uses ball jounts on the spindle vs delilum busings on the Coolster, The cheetah has the exhaust in the traditional route of over the engine and out the back, and the coolster has the exhaust go under the bike, then up and out the back. The cheetah is equipped with a tether kill switch, and the Coolster is not.

With me on the bike (210lbs) it takes a second to get going, but once it does it pulls hard, and is very fun. Im sure the ATV would be a rocket to my son.

NGK Spark Plug # 4629 - C7HSA
https://www.ngk.com/product.aspx?zpid=9618

Front Shocks & Rear shocks
https://www.ebay.com/itm/320mm-12-5-...72.m2749.l2649

Tether strap
https://www.ebay.com/itm/Pro-Armor-K...72.m2749.l2649

Tether kill switch - always open for my model
https://www.rockymountainatvmc.com/p...l-Switch?c=303

2" wheel spacers 4x110
https://www.ebay.com/itm/2pc-2-Thick...72.m2749.l2649

Carburetor - PZ20 with air fuel adjusments
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Weldangrind · 03-14-2018, 11:04 AM

Judging by the size of your boy's shoes, he'll look like a giant on that quad before you know it.

Nice looking machine! Thanks for the write-up.

Bad_Decisions · 01-22-2020, 10:16 AM

Anyone know the correct adjustment for the PZ20 Carburetor? I just put it on my sons Coolster 3125C and can't seem to quite get it correct. It runs but sort of cuts out as he is riding then kicks back in sort of like it chokes for a second.

03-13-2018, 11:02 PM	#1
Douglass Join Date: Aug 2017 Location: Bay Area, CA Posts: 375	2017 Coolster 3125 CX-3 - Build We finally got to take the ATV out for its first run on Sunday. The bike was limitied to at most a 1/4 throttle for my son (5 years old), but drove very well. I decided to replace the carburator, because I could not get the idle to stay consistant. The new carburator bolted right up, and did require a little tweeking. I could use some more, but the ATV runs very good as is. I will wait until I get a little more run time to fine tune it. I did replace the generic spark plug with an Ngk plug, and that seem to be the icing on the cake. Valve adjustment was done after about an hour of light riding As far as the build went after removing the box, there was more bolts than I expected that were not tight enough, the chain was so tight that I could barely spin the rear axle ( this would suck for someone not mechanical). The chain tensioner was not position very well in my opion, so I cut some material off the bracket so the roller would be postioned better on the chain. The right rear hub was not tightened all the way, and had come loose front the factory after the 1st test run, and none of the grease seals had grease on the lips 100% dry. The ATV front shocks are horrible. I could at best get about 1/2" of compression, the rear shock is just ok. I have replaced the front shocks, and will replace the rear shock this weekend. The shocks made a fantastic improvement front and rear, and have adjustable lenght and height. I added a tether kill switch, and a set of 2 inch rear wheel spacers. The kill switch was wired up to the factory kill switch wires near the connector, and routed through the black wire tube to keep it looking factory. The wires were soldered, and wrapped with heat shrink tubing. The wheel spacers came with the needed lugnuts 10x1.25mm thread pitch to install onto the hub, not modifications needed. So far I think it is a great value, but for someone who is not mechanical, it could have been a frustrating purchase. Overall I am mostly happy with the purchase, but my have purchased the TaoTao New Cheetah if I had to do it again. The three main things I noticed between the two is the Cheetah uses ball jounts on the spindle vs delilum busings on the Coolster, The cheetah has the exhaust in the traditional route of over the engine and out the back, and the coolster has the exhaust go under the bike, then up and out the back. The cheetah is equipped with a tether kill switch, and the Coolster is not. With me on the bike (210lbs) it takes a second to get going, but once it does it pulls hard, and is very fun. Im sure the ATV would be a rocket to my son. NGK Spark Plug # 4629 - C7HSA https://www.ngk.com/product.aspx?zpid=9618 Front Shocks & Rear shocks https://www.ebay.com/itm/320mm-12-5-...72.m2749.l2649 Tether strap https://www.ebay.com/itm/Pro-Armor-K...72.m2749.l2649 Tether kill switch - always open for my model https://www.rockymountainatvmc.com/p...l-Switch?c=303 2" wheel spacers 4x110 https://www.ebay.com/itm/2pc-2-Thick...72.m2749.l2649 Carburetor - PZ20 with air fuel adjusments https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1 Last edited by Douglass; 03-14-2018 at 06:41 PM.
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03-14-2018, 11:04 AM	#2
Weldangrind Join Date: Mar 2009 Location: Sardis, BC, Canada Posts: 25,977	Judging by the size of your boy's shoes, he'll look like a giant on that quad before you know it. Nice looking machine! Thanks for the write-up. __________________ Weldangrind "I figure I'm well-prepared for coping with a bike that comes from the factory with unresolved issues and that rewards the self-reliant owner." - Buccaneer
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01-22-2020, 10:16 AM	#3
Bad_Decisions Join Date: Dec 2019 Posts: 23	Anyone know the correct adjustment for the PZ20 Carburetor? I just put it on my sons Coolster 3125C and can't seem to quite get it correct. It runs but sort of cuts out as he is riding then kicks back in sort of like it chokes for a second.
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