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Discussion Starter #1
So i installed a bkp std bore kit and bigger injectors on my 09 teryx and having a lil trouble with getting the tune perfect, mid and high seem ok but it falls on its face on the bottom. If i floor it from a dead stop it bobbles then suddenly picks up and takes off like a bat outta hell. I have an a/f gauge and mostly in the 12 13 range so that seems ok but my butt dyno tells im missing something. Wondering if i should be advancing timing on low end or if maybe i should go back to the stock injectors. This is my first time tuning something so im pretty lost and neighbors are prolly gettin tired of me rippin up and down the road tryin to tune this thing. This was actually my first time building an engine as well and it didnt go to badly, just a couple hiccups along the way but i guess thats to be expected. This is killin me in drag races and tight woods riding. This kit will be awesome power improvement once i get that stutter at bottom fixed and i cant wait but im starting to get frustrated and need some pointers from someone more experienced. BTW i have msd, muzzy std, and bored TB's from dasa if that helps or if anyone has a close map theyd care to shoot me, any advise greatly appreciated.
 

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i feel your pain ,mine does the same thing.outa the hole sucks ,bout 3 grand takes off like a bullet ,if u figure it out tell me what u did. have u did any clutch work yet.
 

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Discussion Starter #3
i have dalton kit but i dont think thats my trouble, are you running bigger injectors?
 

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I hate to be he bearer of bad news but this may be something you can't fix and adding the bored throttle body didn't help matters. You are going from high vacuum at idle to no vacuum when you punch it. There is very little air movement and opening it up with the bored throttle body made it worse.

You made a high rpm machine. 0-10 mph is best served with a small intake and a small exhaust.

About the only thing I can think of that you can do is put a stiffer primary spring in to get RPM up at launch and make sure you have your fly weights set up right.

If you watch the air/fuel gauge when you stab it, it will read rich, not because of too much fuel but not enough air due to no velocity with it opened all up.

I would suggest one set screw and the aluminum rivet on the fly weights

Todd
 

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Discussion Starter #5
I hope this is not the case, dont u think i would've noticed this stutter before, i had the tb's before the std bore kit was installed. Wish i knew someone to loan me stock tb to test your theory. I have my dalton kit set up exactly way you suggested. I may take off airbox lid n see what happens, watcha think.
 

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mine has the stock tbs and does the same thing,dont know what kit u have i have the 12:1 ,stage 2 race cams ,msd ,muzzy pro,bigger injectors ,as long as it is rolling and u stomp it ita run like hell but from a dead stop sucks im thinking its in the cam shafts i m not sure this is new to me .i have a buddy that has the same kit in a brute and it is awsome outa the hole,but carborated. i wonder if anyone else has this problem.,ive even had it on a dyno playing with the timing and fuel cant get it out. its kinda disapointing was alot of$$$$$$$$$$$for it not to be rite.havent had a rzr out run me yet ( 800) that is.
 

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I had bkp pistons,fst stage 3 cams,big TB VFJ injectors,VFJ stage 3 clutch with his weight kit. And 4 in square cut out of air box lid.,uni filter. And it would lay black mark for 20 ft out of the hole. Never stutter Run hard past 75 MPH. Call big kev his customer service is great.
 

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I hope this is not the case, dont u think i would've noticed this stutter before, i had the tb's before the std bore kit was installed. Wish i knew someone to loan me stock tb to test your theory. I have my dalton kit set up exactly way you suggested. I may take off airbox lid n see what happens, watcha think.
Taking the air box lid off is going to make it worse, the intake pressure sensor sees it a s a pressure rise and shoots more fuel.

It is the cams as well as the TB's, carbs do better cause they are vacuum controlled, they don't open just cause your foot is on the floor.

You can make it some better but I have used four different peoples kits and they all do that. Like one person said, once you have it rolling it shoots out like a cannon. On a ATV it is not as bad due to not as much of weight to get moving. Size of tires and vehicle weight plays a roll too.

Very hard to mod something that has low end and top end
 

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Discussion Starter #9
Taking the air box lid off is going to make it worse, the intake pressure sensor sees it a s a pressure rise and shoots more fuel.

It is the cams as well as the TB's, carbs do better cause they are vacuum controlled, they don't open just cause your foot is on the floor.

You can make it some better but I have used four different peoples kits and they all do that. Like one person said, once you have it rolling it shoots out like a cannon. On a ATV it is not as bad due to not as much of weight to get moving. Size of tires and vehicle weight plays a roll too.

Very hard to mod something that has low end and top end
Wish i had known that before i laid down all that $ on kit, valves, injectors, new msd and so on, i tried my best to explain before i puchased kit that my riding conditions were tight trails and tech hill climb with the occasional mud hole thrown in all of which require strong low and mid, i was talked out of a bbk in favor of a std bore ki, wondering if i made wrong choice. I like the power of the kit over stock its just in wrong place for my riding conditions, burping the throttle on a tech climb is just scary now as im not sure where power is gonna come on, im just gonna have to learn to ride diff i guess. Bad thing is po po guys dont consider a drag race from rolling start a valid win and they leave me from a dead stop start
 

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Eez All a can tell you that my 840 had no issue. VFJ had me drill 3 -1 1/2 in holes in air box lit with muzzys and a MSD. Then when I done my 840 cut the top of the lid out. No Drop off any where. Just hit the ped a rock.Did you use kevs XX cams on a standard bore might be to much cam. That's what V force john told me. Go stage 2 on standard & stage 3 on a big bore. Call kev.
 

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Wish i had known that before i laid down all that $ on kit, valves, injectors, new msd and so on, i tried my best to explain before i puchased kit that my riding conditions were tight trails and tech hill climb with the occasional mud hole thrown in all of which require strong low and mid, i was talked out of a bbk in favor of a std bore ki, wondering if i made wrong choice. I like the power of the kit over stock its just in wrong place for my riding conditions, burping the throttle on a tech climb is just scary now as im not sure where power is gonna come on, im just gonna have to learn to ride diff i guess. Bad thing is po po guys dont consider a drag race from rolling start a valid win and they leave me from a dead stop start
I'm only talking about sitting still and nailing it, it should launch anytime you are already moving and normal driving as you mentioned should be much improved.

This even occurred in my Rhino I used to race, stock rhino's would outrun for me for about 20ft then I looked like I was shot out of a cannon!!
 
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