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Joined
1/18/2019
Location
GB
onesev3n
1/19/2019 10:35am
1/19/2019 10:35am
I grew up racing, had fairly good results. Recently got back into it on a 16 Fc450 and I’m happy enough with how I’m riding to justify the cost of a bike build. The problem is I’m clueless as soon as it comes to the engine, anyone have any experience with pulling as much power out of an engine as possible?
THE BIKE NEEDS TO BE RUN ON A DYNO.
Start with setting your TPS sensor to .5!!! This will become THE baseline for your engine tuner.
My bike has a dyno tuned stock ecu, runs pump gas, two stroke filter cage, and a FULL fmf exhaust. The airbox on these bikes are really choked up. Did a dyno run with the box cover on, and box cover off, and there was a .8 of a horsepower with it the cover off.
With those modifications the bike was up a 1.7 hp over stock. But the big advantage was the AIR FUEL RATIO was much cleaner across the board (12.9)AFR. The bike ran awful off the showroom floor.
On a loaded brake dyno my bike pulled 49.97 HP and 29.0 FTLBS of torque. The people who run on a free spinning dyno will probably see numbers closer to 57-59, but they are not accurate to the rear wheel.
What you can do to build big HP
-FULL PORT POLISH and 5 ANGLE VALVE JOB from race tech or X-PRO in andover CT
-Deck Cylinder .005"-.006" whichever race tech recommends
-CP high COMP PISTON
-VP MR12 PRO 6 if you need to be AMA compliant.
-VORTEX RACE IGINITION WITH DYNO TUNED MAP TO YOUR OWN BIKE
-cyroheated internals (any metal part) in the bottom end.
-EVANS coolant to reduce operating temp.
If you're looking for torque, you can have DCR build you a cam. But I'm not a fan of how big of a shim needs to be run in the spring retainer, I have seen them pop out. Also not much for HP gain when they are installed.
Hope that helps. Have tested that set up with 50+ hours on each bike. All bikes pull about 52-55HP on a loaded brake dyno SAFELY and SMOOTHLY.
We have found that the CRANKS are very good from KTM in stock trim. It's VERY hard and VERY expensive to make them better for the amount of money that you need to spend.
The tolerances on these bikes are so tight to begin with, it is very hard to improve what they are without posing catastrophic failure.
And honestly short of building it to be a snow bike, who can actually put 50hp to the ground?!
To me, mapping if the future of tuning dirt bikes. It can dramatically change the power(+ or -) and even how free the bikes feels, which effects your suspension. I think it’s worth trying if you can afford it.
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