I have a QSC STM setup on my mav, Trying to get more on the bottem and less over rev, When I got it it was pre weighted and worked ok but really bogged out of corners and stuff, had 4 grams in cross hole and 1.4 gram in base hole, 0 grams in everything else, Im down to 1.6 grams in cross hole, nothing in the base hole, Center hole has 2.8 grams and the tip has 1.4 grams , its better but it still bogges just not as bad, about 6900 for about 1.5 sec then up to 7500 from a dead stop, still has bad overrev everywhere else 8000+ RPM, I know the butter zone is 7750, but seams like ive added a lot of weight and not much change. Help please
QSC STM Tuning help PLEASE
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Join the crowd. I've been working on this problem with the bottom end and overrev at speed since the clutches were installed. A helix change helped the top but hole shots are sluggish. Kris and Adam from QSC are working on a fix and I hope to be squared away next week. Are you running the gold spring in the secondary?
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Guys, here is my setup….it was pretty close out of the box.
I am at 2700ft but I ride anywhere from 2500ft to 6500ft in elevation.
Primary (QSC)
Spring = silver???
Weights = 3/8" set screws in the cross hole, 1/4" set screw in the base hole, center hole is empty, and a 1/2" set screw in the tip
Secondary (STM Gen II)
Helix = 40 degree w/engine braking
Shims = 2 .03" fiber washers
Spring = PS-13 Gold spring
I am at 2700ft but I ride anywhere from 2500ft to 6500ft in elevation.
Primary (QSC)
Spring = silver???
Weights = 3/8" set screws in the cross hole, 1/4" set screw in the base hole, center hole is empty, and a 1/2" set screw in the tip
Secondary (STM Gen II)
Helix = 40 degree w/engine braking
Shims = 2 .03" fiber washers
Spring = PS-13 Gold spring
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1,319 Posts
What size tire are you running & whats your altitude, any mods? To lower your overrev you will need to add more weight to the tip. The difference between your center & tip look to be a little off, like you might have too much weight in the center hole. I don't have my set-ups in front of me, but I think I would go one size down in the center & one size up in the tip to start. Try to get your overrev dialed in then go after your take off rpm. Ive had too much weight in the center hole/tip & it actually made it bog on take offs as well, so something else to think about. With these clutches, its trial & error to get them dialed.
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394 Posts
If I ran that setup on mine it would be on the gov before it hit 50.
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My setup was very similar if not exactly. Try this it may surprise you.
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Im still trying to dial your setup in for my liking wvxrs. shiftout is still 7450 and I have a rpm drop at 65 mph to 7100. Hoping secondary spring change will fix that. Im trying to get the plate of the primary too, so I can change primary spring. clutch engages at 1500 rpm. I have broke two allen sockets trying to get the screws out. what kind of Loctite did you use? Time to heat things up I guess. I feel like I got a good deal on these clutches, just want to get them perfect.
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Larry... What Helix are you running and tires like asked before... I have a good setup on mine for stock tires..... Getting ready to put on Mongerals so it may change....
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Can you reuse the primary and secondary bolt a second time or should you replace both each time you remove them?
Also I believe it is advisable to use blue lock tight on the bolts correct?
Do you torque the bolts to spec and that is it or do you have to give a extra 180 deg turn like on the stock bolts?
Lastly if you put lock tight on the bolts do you have to let it cure for a few hours before you can run the clutches? If you have to let it cure...... And you break a belt in the field do you then have to sit there for a few hours waiting for the lock tight to cure?
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Also I believe it is advisable to use blue lock tight on the bolts correct?
Do you torque the bolts to spec and that is it or do you have to give a extra 180 deg turn like on the stock bolts?
Lastly if you put lock tight on the bolts do you have to let it cure for a few hours before you can run the clutches? If you have to let it cure...... And you break a belt in the field do you then have to sit there for a few hours waiting for the lock tight to cure?
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Remember, i am at roughly 3000ft elevation. I would start with this and then add a bit of weight to the tip to keep it from over revving. I also noticed belt tension has a big effect as well. I added to shims to my secondary because I thought i was too tight and my RPM's dropped several hundred RPM's. What helix and spring are you running?
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I have. I got these clutches right before Labor Day and have since, with the help of CBP and QSC, tried tons of weight combos and three different helixs. For some reason my machine is just possessed. I had a big ride scheduled for this weekend but due to the government shutdown it got cancelled. Next weekend we are going out on a run and I hope to have it squared away before that.
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The aftermarket clutches come with reusable mounting bolts. it is only the stock secondary that requires replacement after removal.
The blue loctite is required for the stock secondary mounting bolt only.
Torque the bolt to the manufacturer's spec. (i.e. QSC, STM, CVTech or OEM) I believe the stock primary bolt is the only one with a 2 stage torque sequence.
The stock secondary requires the blue loctite and says to allow 6 hours for it to cure before use.
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If you don't have a tuner to dial in your add on's, this might be your problem. Your possibly adding more air than it needs, messing up your a/f ratios. Did you have the bigger throttle body & intake prior to the clutch upgrade? If so, did it act the same way? You might want to put the stock throttle body & intake on it & see if it runs any better. Just a thought.
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So for the QSC and STM bolts I can reuse, brilliant.
Last question would you put blue lock tight on them or not needed. The dealer did not put any on.
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