Full Access, KRX & KRX4 "SOFTER" Primary Clutch Spring



Product Description


Do you need to run a primary spring? The answer is "YES"!

Take it from us, without a primary spring both our shop KRX and KRX4 were not able to even travel 4 miles round trip without hitting 5-6 bars of belt temperature (MAXIMUM TEMP) and pulling over. (Read Story below)

Our new spring will push the primary sheeve with over 50% less force than stock. It will not overload the clutch weights onto the rollers causing premature wear or breakage. It will also lower RPM's by a minor amount.

The KRX and KRX4 1000 need this upgrade. 

1- replacement primary spring

No matter what  companies clutch weights you have, we have found with the softer primary spring it will lower rpm from the power band. It will have less RPM at cruising speed making it nicer to drive, but feel a little less powerfull. If you have adjustable weights, we simply moved our added weight from the tip towards the heal of the weight, or remove the tip weight completely. Simple changes will return any lost performance and increase rpm into the power band. 

This subject has just been beat to death, BUT its back again!
We had a new 15% reduction primary, secondary clutch, Adjustable weights, and a new Badass belt for our 2020 KRX. Also recommended with that setup was to "NOT" run the primary spring.  Our KRX belt temperature guage hardly ever showed 1 bar running all day long. Honestly we felt why even look at it.
With the new set up we hit 3 bars of belt temps within 2 miles, 6 (MAX) bars once we turned around and headed back to the shop! 

We swapped the old primary clutch and secondary clutches back into the KRX to see if that was our issue (180 mile KRX). It was still getting hot. We also went back to the OEM belt and on the same trip, we hit the same temps again. The only variable that was different was that we had "NO" primary spring as recommended.

We put the spring back in and the problem went away immediately. We made the 4 mile round trip with "NO BARS" of temperature. NONE! All the heat was caused from running NO primary spring. We then installed the new 15% primary, secondary, weights, and Badass belt again with the primary spring and have had no issues to date. 2490 miles currently, WITH Spring! 

I shared my findings with our clutch expert and he thought it was odd and that they have had no problems. Then we built our new KRX4 two years later and we experienced all the same problems again. However, this time we quickly fixed it by installing the primary spring. 

A KRX needs a primary spring!
Maybe not on the east coast where you live and dont do over 20 on a trail or something?? But for us and our customers. We ride to get to and from the trails. Some customers even drive them on the roads.

What your telling us and all KRX owners is we are ALL WRONG?
If I did not run a primary spring this KRX and KRX4 would be TRASH to us. Not driveable.  Matter of fact anyone who rides near me would NEVER be able to use them and have to sell them? It sounds crazy, because it is.
Or just run a primary spring and have some fun!

 Sir, not everyone rides the same places, same speeds, with the same weight,  and needs the same things. Running without a primary IMO was not allowing the belt to drive to the bottom of the primary and its simply confused. This occured to us while going down a slight grade, and then up a hill back to the shop.  It causes heat and wear. PERIOD!
For that reason since day one, we have sold weights and say to "KEEP" the primary spring "IN" even though the maker says to not run one.

Twice in the last 6 months I was asked, and then TOLD to stop telling our customer to run a primary spring.
What I told him was, "I WILL NOT LIE TO THEM OR TELL THEM SOMETHING THAT IS NOT TRUE". You sir have warranty issues with weights, and this is not a primary spring issue or my customers fault.  

Common sense! Hey, Kawasaki put it in there for a reason and I, as a Kawasaki KRX EXPERT, and Team member can tell you and my customers with absolute honesty and truth that the primary clutch spring is needed

Multiple customers over the years have also done what he suggested and hated the performance and laziness of the KRX with no spring. Yes, you gain lower RPM at cruzing, but at a higher temperature and causing belt wear. Most mentioned it always felt like the KRX could not find the correct gear and was a pig. 

These things were all discussed over the last 2 years with him. We even thought we were on the path to get a softer replacement primary clutch spring done. But after a clutch weight failure, this guy slandered us and customers online and blamed his part failure on ALL who run a primary spring. Whatever!

So here is what is finally needed! A Primary spring with less force. Maybe this will help him make the right choice, but maybe not and were just the next in his cross hairs to fight with. 

RUN OUR SOFTER PRIMARY SPRING with any weights of your choice! 

Jake Hallenbeck, Full Access UTV! 


  • Model: KRX121
  • 1085 Units in Stock


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This product was added to our catalog on Friday 10 May, 2024.