Polaris ATV Forum banner

Clutch Kit EPI vs QSC 04 700

1 reading
8.9K views 26 replies 6 participants last post by  TDMax  
#1 ·
Hey guys, I have an EPI kit in my Camo 04 700, My wife runs the other 700 and i took it for a spin the other day and the clutching is really not responsive like it used to be.. I ordered a QSC kit for her machine.. I will post my opinions on them both when i get it installed!
The EPI kit in mine woke it up, my engagement was 1600 now its 2100. The kit came with new lighter weights, both springs and a helix..
The QSC kit looks to come with weights and springs but uses the stock helix..
Im excited! wont be if my wifes machine beats me though.
 
  • Like
Reactions: Spidey850
#2 ·
well i got the Qsc installed tonight and took it for a spin. Without a doubt i have way more low end grunt. probably not enough to do a standing wheelie but more snap. I havent ridden much other than around my house to make a comparason. I will write more when i get a chance to do so.
 
#3 ·
Could you clarify: "I have way more low end grunt" Does this mean that your machine with EPI has more than hers with QSC or hers with the QSC now has more than it did stock?
 
#4 ·
actually both quads have more low end grunt compared to their stock clutching.. I have only taken them around the yard (2 acres) and popped wheelies up the ditch.. both quads wheelied at the top of the ditch with ease compared to stock.. as of now i feel the EPI back shift is faster than the QSC kit..I feel the QSC pulls maybe a tick harder from a dead stop than the EPI.
This is only running around my yard, haven't gotten a chance to run them on the trail so i can get an apples to apples comparison.
 
#6 ·
From what little i have ridden them both since the install, the EPI seems to be quicker.. when i let off the throttle and back on it it is right there. The QSC seemed a little slower shifting when i let off the throttle to back on. The EPI engagement is 2200 and the QSC came with 200 rpm shims for the primary spring. I have it set at 1800 rpm engagement. I wanted it kind of tame for the MRS' machine! I dont want her to have to wear her bra backwards! lol
 
#7 ·
Well i took them for an apples to apples run. Both are better than stock that is for sure however, this is what I observed...and remember this is MY opinion.
The QSC has good pull from a slow start, 5mph pulls good up to 50 mph (ran out of road) The backshift is not as crisp as I would like, I noticed the RPMs came on a little low but quickly jumped up, this could mean the secondary is staying open a little to long... I also did a rolling test 40 mph to 50 mph. The QSC pulls harder on the top end than the EPI.
The EPI kit pulls hard on low and mid mph, i felt it did not pull as hard on the rolling test of 40-50 mph, the backshifting is very crisp and aggressive. when i let off and hit the throttle again the rpms hung high and as soon as i was on the gas the machine pulled right now, no hesitation at all.
 
#8 ·
Are you running same size tires on both machines?

What I would like to see is what the cruising RPM is at various speeds and how that compares. In other words 30 mph no load cruises at 4500 one and 5500 on the other. This is likely where the quicker backshifting is coming from.
 
#9 ·
Ask and you shall receive! Stay tuned!
Yes both quads have exact same rim and tire size
 
#10 ·
What I'm seeing is higher spring rate/RPM for the EPI may be making it more of a hot rod feel at the expense of higher RPM all around including cruising.
 
#11 ·
TDMax, I just put the QSC kit in my '15 1000 Touring. Do you happen to know the torque spec on the primary clutch bolt? I know from Ryan's (RVS) video the secondary is 38 Ft-lbs, but no mention of the primary. Thanks!
 
#13 ·
Clutch Kit Install

This clutch kit thing is new to me but figuring it out based on your comments and reviews. Is this a difficult install? I have new machines and will be running stock for a while, but if it's something that makes the ride better I may do it when I can afford it. Just depends on whether I have to afford labor on top of parts.
Thanks!
 
#14 ·
This clutch kit thing is new to me but figuring it out based on your comments and reviews. Is this a difficult install? I have new machines and will be running stock for a while, but if it's something that makes the ride better I may do it when I can afford it. Just depends on whether I have to afford labor on top of parts.
Thanks!
Just my $0.02 - I'd say it's a medium difficulty project, but if you watch the RVS video on YouTube, it makes the major steps very clear and he (Ryan) shows you what tools you need, nothing specialized really other than just a piece of threaded ready-rod and some nuts/washers. I'd say it's well worth it. I haven't ridden mine for real yet, just around my property, but I can tell it's way better. I was going for smoother engagement and more precise control down low and it seems like that really worked. Since mine's a 1000, I didn't feel like I needed to use any primary shims - just don't need more RPMs before it engages. I'd rather have it engage earlier, smoothly so it's easy to crawl over rocks and for loading into the back of my truck. That used to be a little scary because it would engage suddenly and lurch forward.
 
#17 ·
If your QSC kit is the adjustable one you could try adding a touch more weight.
 
#18 ·
This is the non-adjustable version.
 
#19 ·
Drag race:
 
#20 ·
DRAG RACE:
My brother in law and i lined them up. I was on the Blue (QSC) and bro was on my camo (EPI). We were on a black top road. I had my rpms up just before engagement, bro was idling and on the count of 3 we let them rip.. i got a jump of about 1 foot off the line and the EPI pulled right past me and kept pulling.. by the time we reached 50 he was 2-2.5 quad lengths in front. So from a dead stop the EPI won.
 
#22 ·
Stupid random thought, but curious what would happen if you swapped both clutches from machine to machine? That or add a bit of tip weight to the QSC kit and see what that does.

I'm thinking EPI put a lot more time into tuning their kit. Being non adjustable they have to get it right the first time. With the QSC it's a matter of a set of base weights and springs and then just give a guy a recipe to get close to get started.
 
#23 ·
Thats another thing consider, the faster machine might be faster when both are stock? Id love to see what happens when the clutches were swapped but that would depend if the owner really cared to test it lol. QSC is popular here and are good, but EPI and Dalton dont make junk clutch parts either.
 
#25 ·
I'm guessing based on his part throttle cruise observations that the QSC kit is a bit on the light side for his application.