sproket setup

[w.va rider]

What would be the best sprocket set for trail riding? I would like to ride without clutching all the time. I will be going to Hatfield McCoy Trails in a couple weeks and need a good sprocket setup. Has anyone been there? Is it a good spot to ride if you have a sport bike?

[Pappy]

Down one tooth in the front would be my suggestion if your sticking with the stock tires

Hatfield is a blast on a sport quad as long as the trails are so busy. I enjoy both, the big ute's offer a smoother ride but nothing beats letting it rip on a sport quad!

[MtnEX]

The KFX450R is sort of a complicated machine in this aspect.

The reason being is there are a few aspects to consider...

The one you really can't change is that it is a close ratio 5 speed. So close that it is too tall in 1st for low speed stuff and too short in 5th for high speed stuff.

Next is, I can handle the clutching, been riding sport quads since '86.... but I had a terrible time with stalling the KFX without hearing or feeling prior warning.

I noticed this more distinctly when I dropped to a 13t front. It pulled so hard when riding aggressive that it was tiring. Engine braking was stronger. The clutch feathering for speed control was reduced. But the unexpected stalling was still present during slow speed operation, technical stuff, and occasionally even that tap on the back brake. The only difference was the abruptness.

This and a few other things (long story) guided me to replace the stock ECU with an aftermarket ECU.

This fixed every complaint of mine that could be fixed.
And there are a lot of faulty stock ECU's out there...

(been meaning to write a review thread here)


Anyways, the power delivery difference.... I was trying dead engine starts in 1st gear with 13/38 gearing... no go... Jumped straight up to 15/38 gearing and have to launch in 3rd to keep from ending up on my head.

It's way taller now in 1st with the 15t, but it has way more stall resistance and way less gear changing.

But in the end, the internal trans gearing is still too tall (fast) in first. So it will never crawl around in 1st gear with no clutching like a 400EX will.

If I ever have to open my bottom end, I am at least going to look into rather or not there is an easy change that can happen to slow down first gear a little or something.

[w.va rider]

MtNEx. Are you suggesting going with a 15 front sprocket? What is the best sprockets to buy now days? I dont know much about the sidewinders but have heard some good things about Renthal? Opinion

[MtnEX]

Originally posted by w.va rider
MtNEx. Are you suggesting going with a 15 front sprocket? What is the best sprockets to buy now days? I dont know much about the sidewinders but have heard some good things about Renthal? Opinion

I recommend plain jane steel sprockets for this application, torque-down of rear sprocket bolts, and periodic inspection.

This is to avoid breaking sprockets and chains, and whatever else gets hit.


As for the sprockets, this is what I recommend doing....

Go to RM ATV and order Primary Drive sprockets for it. Steel and inexpensive.

From what they offer, pick up a 13t & 15t front.... and also the 39t rear.

This along with your stock 14/38 will give you several combinations to play with.

Right now, you will probably like the 13t front for casual riding. If you start riding harder or adding mods though, the pull will make you tired and you'll be sick of shifting gears.

Later on down the road after mods you'll be glad you have a 15t laying around also.


This suggestion offers you the following combos...

13/39
13/38
14/39
14/38
15/39
15/38

[KAWIRYDER]

I did the 13 tooth on the primary drive and I love it now. It has the crawling gear I wanted in 1st gear. Now 2nd gear is amazing for the power I want when I need to hop over a log or rocks. You will really like the feeling of a 13 tooth primary.:D

[MtnEX]

As I move through my mod stages here, I need to go back and play with gearing...

How the thing pulls through the gears changes as you go. I know that much already.

Adding the Jardine exhaust for example improved the flow a lot and stopped it from winding up a gear so fast or I should say more accurately.... it kept it from falling flat so soon... which lengthens the gears and reduces shift frequency.

I had to shift a lot real quick before... that was the only down side of the 13t before. After mods it was the spinning and the exhausting pull when riding aggressively.


I have a cordless impact, so changing between 13/14/15 fronts is pretty quick and easy... longest part is the chain adjustment.... And rear changes wouldn't be a lot worse... just a few more nuts/bolts.

Point being, I used to swap between 14 and 13 depending on where I was going that ride, and who I was riding with. I haven't done that in a while, but should try it now just to see where I am...