2020 Husky 501 OR 2020 YZ450

[CB-BLR]

Got back from the dyno yesterday with the PR2 throttle body bore installed:
63.9 hp as compared to 60.7 with the stock throttle body.
Torque came up from 40 ft/lbs to 42.1 ft lbs.

We then removed the side cover to the air cleaner...and picked up another .9 hp and another .4 lbs of torque bringing the numbers to 64.8 hp and 42.5 ft lbs of torque.

I understand that not all dyno's are the same and that some read higher or lower than others...but the throttle body bore legitimately increased hp by 4hp and torque by 2-3 ft/lbs everywhere...comparing on the same dyno...but about a month apart. It is the increase that is of note...not the actual numbers.

This mod works!
Riding the bike on the street...it pulled quicker and with more authority everywhere!
Time to install the TS setup.

Now I just need to figure out how to get more air into the air box without letting snow in.

Chris

 

[dooman92]

Chris, thanks for the update. Good to know I didn't waste money on the throttle bore. Sounds like the biggest remaining difference between our engines is the head. Any ideas how much difference the head makes?
Regarding more air and the air box, just as an idea, I will attemp to post pictures of what I did. I don't have a photo of the inside the air box because I have to remove prefilter to show the ktm sand prefilter that covers the stock cage (foam filter removed) which I modified a bit to increase surface area. If the photos post they show that I used a hole saw to open holes in side cover and the portion of the air box that faces the rear tire area. I placed prefilter material over all theses holes. I also covered the side cover area with prefilter, and any area where snow might be sucked in. It works good and I think I have increased air flow compared to the stock air box. If needed for dirt the foam filter could be used. I did not have a single snow plugging issue this past season. A few times I pulled off side cover and removed a bit of accumulation.

 

[CB-BLR]

I think the differences in the motors are for the 2020:
The head off the previous generation 450sx
The cam
A higher compression piston
A lighter reciprocating assembly
Supposedly a little better breathing air box...the dyno guy said that previous years yielded about a 1.6 hp increase when removing the side cover.

Thank you for the pics of your airbox mods...I was thinking something similar, and using the round frogzskin inserts in a few places...including the cover:

Frogzskin | Offroad Hydrophobic Mesh Filters | Vail Colorado

Previous Next

www.frogzskin.com

Chris

 

[byeatts]

Got back from the dyno yesterday with the PR2 throttle body bore installed:
63.9 hp as compared to 60.7 with the stock throttle body.
Torque came up from 40 ft/lbs to 42.1 ft lbs.

We then removed the side cover to the air cleaner...and picked up another .9 hp and another .4 lbs of torque bringing the numbers to 64.8 hp and 42.5 ft lbs of torque.

I understand that not all dyno's are the same and that some read higher or lower than others...but the throttle body bore legitimately increased hp by 4hp and torque by 2-3 ft/lbs everywhere...comparing on the same dyno...but about a month apart. It is the increase that is of note...not the actual numbers.

This mod works!
Riding the bike on the street...it pulled quicker and with more authority everywhere!
Time to install the TS setup.

Now I just need to figure out how to get more air into the air box without letting snow in.

Chris

did the bored throttle body require changes in the fueling?

 

[dooman92]

Chris, interesting, makes a new bike more attractive. Sure would like to dyno mine to see difference. I have a little higher compression piston, but cam and head might make big difference.
We had a negative experience on a 19' 450 yz. One of my buddies was having difficulty with pulling gears at high elevation on his yz. Tried different maps, air temp sensor relocate and different ecu. He finally put a heavier flywheel assembly on it and it pulled a gear higher. He was much happier after the heavier setup?

How about vibration between the 18 and 20? Any differences. That is my biggest complaint about my 500.

 

[CB-BLR]

did the bored throttle body require changes in the fueling?

Yes...it required quite a bit of richening across the entire rpm range.

 

[CB-BLR]

Chris, interesting, makes a new bike more attractive. Sure would like to dyno mine to see difference. I have a little higher compression piston, but cam and head might make big difference.
We had a negative experience on a 19' 450 yz. One of my buddies was having difficulty with pulling gears at high elevation on his yz. Tried different maps, air temp sensor relocate and different ecu. He finally put a heavier flywheel assembly on it and it pulled a gear higher. He was much happier after the heavier setup?

How about vibration between the 18 and 20? Any differences. That is my biggest complaint about my 500.

The 2020 has a lighter rotating assembly...and yes...the 2020 vibrates less and revs quicker than the 2018 bike. I have been told by my dyno guy that replacing the piston with a light weight Vertex piston makes it rev even quicker and smoother...with an additional 2hp and more torque. It is my understanding that Vertex makes the stock piston for this bike...but that the aftermarket one is both lighter and stronger.

 

[dooman92]

Chris, good to know about the improved vibration. I know that on my 18' the stock piston was a mahle piston. Might be different for 2020. I got the replacement h/c piston from Jeff at pr2. It was a bit heavier than the stock mahle I took out. It also used the very thin rings that were stock with the mahle piston.

I think I read somewhere that vertex made the two stoke Pistons for ktm.

Did you accomplish increasing the fuel with the setting knobs on the vortex or reprogramming?

 

[CB-BLR]

Fueling adjustments were accomplished by reprogramming the Vortex as they were well outside both the resolution and adjustment range of the dials.

Chris

 

[dooman92]

Chris, so your dyno guy can reprogram the vortex? I think I added a little fuel with the dials after talking to Jeff following my throttle bore but never reprogrammed. I'm thinking I only increased slightly. I might have to try more with dials. Did you go to the limit of the dials and still needed more?

 

[CB-BLR]

Chris, so your dyno guy can reprogram the vortex? I think I added a little fuel with the dials after talking to Jeff following my throttle bore but never reprogrammed. I'm thinking I only increased slightly. I might have to try more with dials. Did you go to the limit of the dials and still needed more?

Yes...he reprogrammed the Vortex using their software license from Vortex, along with the correct cable from Vortex. He put all of the dials at the center position...and then just worked the tables on the software for about an hour to get the correct jetting and timing for each cel (like on EXCEL). The dials have nowhere enough adjustability in both range nor resolution. I believe any competent dyno person can do this...but he tunes and dyno's about 10+ bikes a day...Mostly for track guys...ie motocross, super-moto, and big hp track bikes. I believe he tuned the bike that won the single cylinder class at pikes peak this last year.

https://2wheeldynoworks.com/

They also can flash many stock ECU's...

I don't think there is a "one size fits all" tune for most bikes...they will work better on some bikes than others.
Custom tuning on a dyno for your area is the only viable way to go.

Chris

 

[Lachoneus]

Good stuff guys...any idea who does this well in southern/southwest or eastern Idaho?[/QUOTE]

 

[wwillf01]

Closest one I know is proven moto in utah.. he has done many snowbikes and pro racing engines

Sent from my SM-F916U1 using Tapatalk

 

[dooman92]

Wow, checked out the website, great resource. That thing should rip on the snow. Any comparison info throughout the season would be interesting.

 

[roxiedog13]

Yz all day. Way more fun and playful than a 500 in my opinion.

Why the YZ over the Husky 501? I actually purchased a 2014 KTM 450 SX-F today . I chose it over a 2017 YZ and 2017 Honda CRF because neither had electric start . BTW, I ended up with a new 2021 Timbersled ARO 129 LE, figured just as well to go new on the sled for the price difference. Appreciated your help previously , this is why I went with the TS 129.

Now I'll need a thermostat, engine wrap, hand warmers, hand guards and skid plate. Any suggestions as to where to go for these items ?

 

[RmK8oo]

CB-BLR, here’s the setup on my 501. I’m running a Loudmouth intake with outerwear and frogzskin vents on the side panel. I have zero issues with snow buildup in the airbox. The Frogzskin vents seem to flow very well, foam filter was always dirtiest directly behind those vents when the wheels were on the bike. I made a template that can be taped to the side panel and used to trace out both holes that need to be cut in the proper position for the vents. If, anybody decides to run these vents on their Husky let me know and I’ll see if I can find that template and email a copy.

 

[Lachoneus]

CB-BLR, here’s the setup on my 501. I’m running a Loudmouth intake with outerwear and frogzskin vents on the side panel. I have zero issues with snow buildup in the airbox. The Frogzskin vents seem to flow very well, foam filter was always dirtiest directly behind those vents when the wheels were on the bike. I made a template that can be taped to the side panel and used to trace out both holes that need to be cut in the proper position for the vents. If, anybody decides to run these vents on their Husky let me know and I’ll see if I can find that template and email a copy.

nice work there buddy, looks great.

 

[cisco]

CB-BLR, here’s the setup on my 501. I’m running a Loudmouth intake with outerwear and frogzskin vents on the side panel. I have zero issues with snow buildup in the airbox. The Frogzskin vents seem to flow very well, foam filter was always dirtiest directly behind those vents when the wheels were on the bike. I made a template that can be taped to the side panel and used to trace out both holes that need to be cut in the proper position for the vents. If, anybody decides to run these vents on their Husky let me know and I’ll see if I can find that template and email a copy.

outch 249$ .
i was all in about your ides but not at 249$

 

[CB_Rob]

Did the YZ450f bottom end issues ever get fixed?

Has there been a trend of these failing early continuing on

 

[CB_Rob]

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