BlueBlood207
Newbie
Hey guys i've searched through the forum for days now trying to figure out why my 2011 apex xtx will only pull 10,000 or 10,100 with a 150lb rider on it. Ive replaced the clutch springs and rear secondary buttons as well as installed a new 8dn belt. I have checked all bearings and even went as far as buying a pc5 and did the intake mod with hurricane map. I dont know if its running out of fuel or what. I did however remove the exup last winter..My question is would removing the exup effect my peak rpms that much? The only other thing I can think of would be the valves..would valve adjustment cause lower rpms?The sled has 14k on it. If someone could point me in the right direction I would appreiate it very much. Thanks
Eric
Eric
Stock primary?? What helix do you have and what is the setting??
Macheater
VIP Member
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What do you mean you removed the exup. Did you put Ulmers system on it?
BlueBlood207
Newbie
Stock primary new bsb spring. The secondary is stock i believe it says 8bvfs i believe. Pink secondary set at 70. If the valves needed to be shimmed would that cause loss of power up top?It pulls better than it ever has but I noticed it only turns 10,1..I just replaced the donuts 20 miles ago and installed mbrp trail can. stock gearing.
BlueBlood207
Newbie
No I welded on new header flanges and while I was there I removed the exup valve assembly but left everything else including the servo attached. I did that at the end of last winter and cant remember testing rpms afterwards.
BlueBlood207
Newbie
I thought maybe it was the new buttons i installed but I figured id ask you guys.Been forever since ive been on ty I had to start a new account lol.
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might be the mbrp can. might have to pull some tip weight for it to run right.
BlueBlood207
Newbie
In other words I waisted money for less performance. The sled sat for awhile without fuel in the tank and may have had some dirty fuel/water dumped in..i'm curious if a failing fuel pump would cause lower peak rpms only at wot?
mbarryracing
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The primary clutch is like a mini dyno on the end of your crank. When everything is unchanged in clutching (especially with a new spring) then when it's running lower RPM it's making less power, if it's running higher RPM it's making more power.
You disrupted the tuning of the exhaust system, intake system, and camshaft profile combo when you altered the exhaust back pressure and installed the can so now it's making less power.
maim is right, you will need to take tip weight out to get it to rev higher.
You disrupted the tuning of the exhaust system, intake system, and camshaft profile combo when you altered the exhaust back pressure and installed the can so now it's making less power.
maim is right, you will need to take tip weight out to get it to rev higher.
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BlueBlood207
Newbie
So by taking weight off of the tip of the weight to add rpms will bring my power back up? I guess i'm lost because I thought one would end up with more rpms after adding better flowing exhaust,pc5 and intake modification..it seems like to me having to take weight out of the clutch to get the proper rpm would be less power period..if you dont mind explaining alittle more I would appreciate it. Thanks
Stubbs
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If your PCV isn’t mapped for the exhaust change you may be lean up top, resulting in low RPM. I’ve had really good luck with Allen Ulmer’s mapping over the years. I’d get a hold of him and describe in detail EXACTLY what you’ve done mod wise, and have him send you a map for that specifically. No disrespect to Dave at Hurricane, because I run his full kit in my mod Nytro and love it, but his ‘11 + Apex power up kit didn’t get great feedback here on the site. Once you know you’ve got decent mapping in that PCV for your complete set of mods you can attack the clutching.
Pete_man26
Extreme
Are you running an AFR gauge? That will be the only way to tell if you are lean or rich. Without that, having a PC5 is almost useless as your are guessing. Just my opinion.
BlueBlood207
Newbie
It was a late night last night but I was determined to figure this out. I gained 700 rpm and a leaky gas tank by the end of it to be exact. The sled performed the same on hard packed as it did in 6 inch fluff tonight at -3 *F. Pretty much it would make a clean sweep in rpms from any SPEED you wack it at to 10,300-10,400 and climb to 10,700 and most likely more but I could'nt hold it long as I had to keep the gas level below the pump mounting area..I ended up with a leaky fuel tank but god darnit we have rpms. did two things both in relation to the fuel supply so unfortunately im not sure which one fixed it. I removed my fuel pump and sprayed the strainer out cleaned it as good as possible tested it out in a bucket of fuel....all looked well..then I installed the pump and filled the tank per directions with a few gallons of gas and half a bottle of CATACLEAN. I then drove it for ten minutes and refueled and walla...animal mode with my 150lb butt. just thought I would share that with anyone interested. Thanks for the advice as well.
Pete_man26
Extreme
clutching sounds almost perfect, 10300 and creep up to 10700-10800 is exactly what you want.
ssgzag15
Extreme
Exup only activates at mid range, is wide open at 'Wide Open'
