Author Topic: Mongoose 300 cvt upgrade questions  (Read 2718 times)

Jonesy23

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Mongoose 300 cvt upgrade questions
« on: February 22, 2015, 03:10:10 AM »
Hi, new to the forum and new to Kymco. I have a Mongoose 300 and I would like to upgrade to Dr pulley sliders to improve acceleration and will probably change out the big clutch spring to a red one.
Does anybody know what size and weight the stock rollers are? I want to go lighter.
Also, any other resources for exhaust, carb jetting ( what size is stock) any cam options?
Thanks for any help.

zombie

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Re: Mongoose 300 cvt upgrade questions
« Reply #1 on: February 22, 2015, 03:51:03 AM »
Welcome to the forum Jonesy!

If you don't get answers tonight I'll be happy to look around for you in the morning.
Dead tired, and 3/4 full of Fireball Whiskey.

Peace!!!
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

Jonesy23

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Re: Mongoose 300 cvt upgrade questions
« Reply #2 on: February 22, 2015, 10:19:36 PM »
Any help would be appreciate. I'd also like to go with lighter clutch springs.

zombie

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Re: Mongoose 300 cvt upgrade questions
« Reply #3 on: February 23, 2015, 12:56:00 AM »
http://www.kymcoforum.com/index.php?topic=26.0

This thread might help some.

I haven't found the exact roller weight yet.

General rule is go 4-5 grams lighter on 250 - 500 cc bikes.

That thread mentioned 20 gram rollers on a wish lisThey were also talking about a work horse, and you have an MX type bike... I get it.

You are on the right track with the rollers / control spring, and the clutch fly springs.

Getting more RPM, later lock up, and a better gear ratio at lower RPM will all help get more torque on the ground.
« Last Edit: February 23, 2015, 12:59:17 AM by zombie »
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

Jonesy23

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Re: Mongoose 300 cvt upgrade questions
« Reply #4 on: February 25, 2015, 12:29:53 AM »
I did some searching using the stock part number and it appears that they are 23 x 18 25g in case anyone else finds this thread and wants to know.
I ordered a set of Dr Pulley 22g sliders, if they don't give the boost in low end that I want then I will try a 1500 rpm clutch spring.
The only other mods I may try is a set of wheel spacers and maybe some different shocks. Motor mods don't seem to pay off for the investment, at least based on the info I've read.
I'll reply back once I get the sliders in.

zombie

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Re: Mongoose 300 cvt upgrade questions
« Reply #5 on: February 25, 2015, 01:03:30 AM »
We appreciate the info Jonsey. It will help the next fella.

The 1500 spring will hold a lower gear ratio longer, allowing more torque on acceleration. That is the largest bang for the buck mod you can get.

Rollers will give you higher rpm, and the spring will hold them longer. It's a good combo package.

Please do keep us informed.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

Jonesy23

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Re: Mongoose 300 cvt upgrade questions
« Reply #6 on: March 14, 2015, 02:14:39 AM »
Update. I installed the 22g dr pulley sliders, I noticed a slight improvement in the upper mid range but nothing to write home about so I got an EPI maroon secondary spring and a set of main clutch springs. There is now a noticeable improvement in the low and mid range as well as a downshift feel when decelerating. It gives a great mid range response and keeps the motor revs up when coming out of a corner.  I have another 300 that I left stock so I am able to feel the difference. The only negative is that the revs are much higher now at slow cruise and midrange.
Next mod is to remove the flame arrester, higher flow air filter, remove air box lid and rejet the xarb.
Today I pulled the spark arrester, cleaned the air filter, removed the pre filter and air box lid and I couldn't get the quad to do any more than idle, advancing the throttle or going wot would stall it which tells me it need more fuel so I'm now looking for a jet kit but in the mean time put everything back to stock and all runs good.

zombie

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Re: Mongoose 300 cvt upgrade questions
« Reply #7 on: March 15, 2015, 04:48:34 PM »
That's GREAT to hear Jonesy.

Thanks for keeping us updated.

You are 100% correct on the jetting. You will need a FEW main jet, and most likely 2 steps up on the pilot to get the free flow set up to work.

It's always best to start way rich, and go leaner until it runs right. Going the other way can deceive you into thinking it is rich enough, and you start melting valves.

I love it when someone starts really liking their machine.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

BettinANDlosing

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Re: Mongoose 300 cvt upgrade questions
« Reply #8 on: March 15, 2015, 06:10:23 PM »
Keep in mind for an off road vehicle they put the snorkel on there for a reason, you'll be cleaning a pod filter every time you go wheeling.
2002 Kymco B&W 300; MRP 78MM "300CC", Naraku cam, Yoshimura rS3 exhaust, 17g Sliders, Yellow torque spring drilled airbox, stock carb #115 main #40 pj.

2001 "Yamaha" Zuma AKA MBK Booster; MHR OverRange, Dellorto 19mm BHBG, Polini "big" intake, RS-3 Rear shock, Stock cylinder.

zombie

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Re: Mongoose 300 cvt upgrade questions
« Reply #9 on: March 15, 2015, 08:50:07 PM »
100% correct.

When I raced 500cc Moto X I changed the oil after EVERY heat. I had boxes full of pods, and the chain / piston rings got replaced every 10th weekend.

Dirt IS the killer of engines.
"They have nothing in their whole imperial arsenal that can break the spirit of one Irishman who doesn't want to be broken."   Bobby Sands...

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