Posts
451
Joined
11/19/2017
Location
Pittsburgh, PA
US
Edited Date/Time
2/19/2019 2:08pm
Just got a new 18 450sxf and have a few questions..
I did the 280mm braking setup with cm46 pads, ordered full yosh, and made my own throttle cam mod for a 1/7turn throttle.
-Will I need to do any ecu changes to it with the full system?
-I swapped over the radiator shrouds plastics front fender and seat from my 18 250sx, what other pieces are compatible?
-what levers will bolt in place for the brake/clutch? anything with an adjustable lever ratio for clutch or brake side?
-what else should I do to it to uncork it?
-reserved space for more further questions as I think of them
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I did the 280mm braking setup with cm46 pads, ordered full yosh, and made my own throttle cam mod for a 1/7turn throttle.
-Will I need to do any ecu changes to it with the full system?
-I swapped over the radiator shrouds plastics front fender and seat from my 18 250sx, what other pieces are compatible?
-what levers will bolt in place for the brake/clutch? anything with an adjustable lever ratio for clutch or brake side?
-what else should I do to it to uncork it?
-reserved space for more further questions as I think of them
-
-
The brakes, im not 100% sure if doing the 280 kit would make it grab more but the KTM brakes are amazing. Not sure why you would want it to be so aggresive? More aggresive pads will just “eat” through rotors quicker.
Levers. ASV/Arc’s are the best. Even the KTM powerparts levers are awesome and come in orange!
Plastics. I doubt the rear end will work. Maybe the airbox cover but thats probably it as the 4ts are different molds. At least between out 17 300 and my 16 350sxf.
ECU settings will uncork it a bit but if you really want insane power you could always bore it over and remap it.
GL
-went to look at the number plates by exhaust look a little different, didn't want to take both apart to find the rest didn't fit without checking first. The yosh looks really good to me, as in jewelry good plus I have a full yosh on the rmz450 that I love.
https://www.ebay.com/itm/Yosh-RS-4-Signature-Series-Exhaust-System-Stai…
here is their website, I hate these bogus dynes tho...
-Ecu, Tokyomods website is insanely bad, what am I getting? what is the cost? What is the issue that we are trying to achieve here? another 1* advanced timing and like 1-3% richer for the full system?
The Shop
This bike makes the right kind of power for me unlike my 250sx that is for sale w 2hrs on it. I just of course will take more cheap power with exhaust and tune, just want to know what the options and feedback are. deff NOT opening this motor. Already know this is the bike I should have bought all along. Just looking to do all the easy enhancements now while we have bad weather for the next week at least.
also who has increased rev limiter 500rpm+?
You don’t need to remap the bike for an exhaust, Twisted Development has some awesome maps to make more power and more ridable power.
You can go to a screenless filter cage like a ktm 2 stroke cage.
VP T4 fuel is great.
I was able to make my own throttle cam mod today along with no waffle thin grips and I now have a laser quick on off switch that I like.
This will unleash some horseshit.
I ended up getting full custom graphics ordered and a white tail and blue factory seat cover so should look trick
https://www.keeferinctesting.com/motocross-testing/2019/2/5/nbsp50-hour…
I understand the exhaust, it looks cool. I do it too. The throttle cam, great, especially if you have some ailment in your wrist and the shorter throw improves ride ability and comfort. Budget your resources towards improving those two things; ride ability & comfort. You made no mention of proper chassis balance & set up or suspension tuning. The AER forks that come equipped on those bikes are notoriously difficult to set up. Maybe I’m underestimating you and you’ve already considered these vital items?
As far as maintenance intervals go... A local pro and two-digit FIM/AMA number plate holder, Chris Canning, just went through the entire 2018 race season on the original KTM bottom end and only changed piston/rings/etc once. Over 100 hours on the bike. Suffice to say you will have no problem going 50+ hours without a problem, assuming all regular maintenance gets performed adequately. Your manual will tell you when to perform all rebuilds, but there are so many variances with rider skills that there is no definitive answer. One rider may spend most of their ride time at 7500-10000 rpm, where another rides the bike at max RPM for hours on end. This drastically effects when the motor needs to be rebuilt.
So many people enter the MX/off-road world with experience from another power sport. Not everything from the snowmobile/super-bike world applies to MX. The latest crop of MX bikes are so close to optimal performance out of the box compared to ATV/Sled/race cars which require endless mods to be race ready. Or maybe it’s the culture of those other Motorsports that teaches them to modify everything? They go down the rabbit hole tuning their machines and exhausting resources that never improve their results. I have many friends like this that are genuinely trying to improve their rank by looking for some expensive, elusive mod that will dramatically improve their results. Other people just like to tinker and mod their bike like it’s an import show car. I get that too, but those people usually aren’t worried about being fast on the track but still love to be part of the scene.
My suggestion is to ride the bike first and then address any faults you have. For that bike, ergonomics and the AER forks are just about the only legitimate complaints one can have. In addition to that you should be aware of how to adapt and ride around the bikes “flaws”. For example, if you don’t like the way the front brake performs, I would suggest going over braking fundamentals and learning when and how to properly use the brakes. People tend to blame the bike for the faults before addressing problems with their technique.
Just my opinion and maybe this doesn’t apply to you at all. But I do come across this type of person often.
thanks for the reply, I want to get the driveline sorted first as I have flat property at my house and can tune/adjust and have that all sorted out perfectly during the rest of winter before tracks start opening. I never achieved my potential in the mx world due to non stop wrist injuries so I got out completely for a long time and now everything is efi & 4 stroke and way more electronics that I need to get a handle on how to fix lean conditions or retarded timing that manufactures are doing to every vehicle these days to help idiot proof them.
I have a good understanding of handling and suspension tuning as I was a chassis/suspension engineer in the car world. the estimated hrs on it are going to be strictly "serious" hrs only on that bike out of many bikes (going to get a few more and vintage)
I think the motors are pretty weak compared to the street bike world and just dont last the same hrs at the same "level" of use... ktm 120whp/litre vs 190whp/litre
obviously the idiot on the bike (me) is the critical thing to going fast but I have the money and pro auto racing background so I of course have to have all the low hanging fruit I can on the equipment.
Glad this forum exists and that there are a lot of experienced and skilled riders & tuners on it, especially on the ktm side.
Mapping the ECU to alter the air/fuel ratio at different intervals throughout the RPM range seems to be where the MX engine tech’s are spending a lot of their time. Through dyno runs and lots real of real world testing, tech’s are altering the air/fuel ratio to complement a comprehensive view of all engine specs. Everything from fuel, engine & associated componentry, ambient temperature, altitude and more is accounted for. Generally on a 450, they will develop the map to broaden and smooth the curve. Re-Mapping services from Twisted Development, Tokyo Mods, or any other reputable company will run you about $100. There are some on the east coast too, they may have a better idea about local tracks and conditions. You’re right about the bikes coming too lean from the factory to pass emission testing. A proper ECU tune will correct that and is definitely one of the low-hanging fruits.
On a bit of a tangent but...
I have only heard of one other person here comment about the lack of power from a 450. IIRC, he also had a street bike background. I think once you throw in challenging track conditions and long motos, you’ll find a 450 to be quite a handful. I honestly don’t believe a MX racer would benefit from a more powerful engine than the current 450s. Manufacturers have no reason to make a 70hp off-road race bike because the market doesnt demand it. Whereas the road racers can actually benefit from 190hp vs say 160hp? IDK to be honest.
I can understand you would find the power is underwhelming compared to a street bike, especially in a field or groomed track. But under race conditions, you may find you can put in a better moto on a tamer,stock engine than an aggressively hitting, stamina draining power plant.
Or maybe not. In that case, another low hanging fruit is to remove the back fire screen in the filter cage. The two stroke SX’s have no screen in the cage and can be fitted to the SXF’s. Be sure to Mention that mod to the person that is doing the remap too.
I’m curious, with your street bikeground, what separates the two engines that the street motor is capable of 190hp/liter vs the dirt motor? Which by my calculation is more like 130hp/liter. Doesn’t the fact it gets to share the load with 4 cylinders help push the envelope of max HP? As far as I knew, a MX-450 (especially KTM) is the most powerful single cylinder I.C.E. made per CC.
Pit Row
I did some research between the Tokyo Mods and TD flashing and read on here specifically on multiple threads that the TM flash a lot of people thought it made no or very little difference and the TD flash was "hands down winner" with no scientific or mechanical data to back it up.
I have a software program for my mv agusta called ECU studio that is a full suite to every single thing for its electronics form the autoblipper to water based or IAT based ignition/fueling, per gear, etc etc etc and it was only 700$ which I used myself and have an impressive (stock internal) running bike (675cc 133whp pump) or my new gsxr 1000 which just has a full akra, race filter, emissions block offs and a run of the mill mail in flash for approx 191whp, Guys are seeing well over 200whp same setup with race gas and a dyno tune. Not sure why the hp/litre is so dramatically better than the mx world, the 250sxf is the highest assuming the 42whp pic I saw is legit. its the same capacity per cylinder as a modern day litre bike that all make 180-190whp, the 250sxf revs a little slower at 14 vs 14-15k and sees the same 10k+ only the entire time its on the track and the stroke length is similar so piston speed is about the same. Im not expert in why but I dont think there is any reason I can think of why a 250sxf makes less than 48whp. stock.
If I could have something even extremely basic like what I watched on youtube for the Yamaha for the cellphone app I would be able to get the bike riding perfect from a feeling stand point which isnt going to be the most power but it will be the most rideable power.
Is there a tuning system like the Yamaha for the ktm? id rather put my money on that than about 300 shipped for the TD flash which is obviously going to be a guessing game based on fuel, alt, temp & humidity.
*if some if this didn't make sense its because I had "some" scotch
https://m.vitalmx.com/features/ECU-101-Tuning-Mapping-and-the-Future,6360
As far as the linkage goes, anyone have dyno's of the stock rear shock and swingarm movement? which direction of non linear movement is the linkage going?
https://luxonmx.com/products-suspension.html
If you're asking about the other relay arm on that page (the black one), it's identical to stock geometry. We made a short run of those before we developed the N2D versions. Only have a handful left and we're blowing them out since the N2D ones work so much better than the stock geometry.
Perfect sag for me with Trax shock at 195lbs without gear was 46nm (105/40), and with PC linkage 50nm landed me spot on 105/40.
Have not tested with the old 2015 linkarm and knuckle but i would most likely be at 60nm or so. Quiet common to run the 2015 SXF linkage on 2016+ models.
Longer linkarm does not do much for the suspension on 2016+ chassi if you ask me. I have tested +1mm to 2.5mm and you have to compensate with lower sag for every 1mm longer linkage if you want to maintain front end pressure (not turning, but pressure). You still have that strange curve or stiff begining.
For our 2nd generation link (the blue one, current version), we reduced the progressiveness a bit (still much more progressive than stock) and fixed the geometry so there's more swingarm clearance. We came to the current design through a bunch of computer simulations and finally on-track testing of stock, version 1, and version 2 linkages. All test riders agreed that the V2 linkage was the best. It's not an enormous difference from V1, but it's certainly better. Both V1 and V2 are far better than stock, but you have to change your spring rate and valving to suit.
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