anyone done/do it? bike in question is a 2020 husqvarna fs450.. i finally fabbed up a belly pan from an acerbis skid plate and a bunch of fiberglass and i’m thinking of doing a some big track racing with it next round. track config is 2.2 miles and not any super long straights (umc east), but that’s on a sport bike.. i’m sure they’ll feel long on a dirtbike. i’d be in the production 500 class and the moto3 class.. so i’d be racing against ninja 400’s and the like. anyone done this? i’m going to one up the front sprocket, but almost wondering if i need to two down the rear.. i won’t have any track time prior to race day to test gearing. if anything it’ll be some fun shits and giggles. i just hope i’m not bouncing off the rev limiter the whole day.
You will need to go down a lot further than 1 or 2 in the rear. They top out super easy on any real straights. Its been a long time but I had a KTM 520 that I had wheels and brakes on and it was a blast for sure.
The motor would not like big tracks but it could be done, you would need to go down few teeth on the back. Also I would shorten the back of the front fender. . For sure you will be hitting rev limiter with stock gearing. High maintenance, but you will smoke A 400 ninja.
What changes in the maintenance schedule? It already requires a lot of maintenance and basically a full rebuild at 100hrs... Interesting thought about the front fender
The front fender will make the front end dance a little on high speed. Regular maintenance but more often. I did not have a good luck with Supermoto on big tracks as I blew the motor bouncing off the rev limiter.
When I ran the crf450 in Jennings ( not a bad track for that bike.) I went I think 10 teeth down from stock.
Check out gearing commander to play with some different gearing for it. Error on the tall side, because you don't want to blow it up. https://www.gearingcommander.com/
I ran mine at barber and lots of people race them with ahrm. Get a 15thooth front sprocket and a few options of small sprockets for the rear from vortex. You'll need a different chain also 15/38 or 39 should make it fun and not over rev. 14/45 should be stock
I used to race an 03 YZ450(with WR tranny) at BIR, VIR and MAM in 05-08. Never had any reliability issues. Gear it tall. I ran 16/36, if I remember correctly. The single biggest piece of advice I can give anyone, is DO NOT use engine braking! Don't try backing it in, either, unless you're really fast and its a really slow corner. Even then, use only the rear brake. I found out just how deep you can go when racing Scott Carpenter on a 550 Ape. We kept outbreaking each other till I went so deep I had a knee down, sliding the front end and grabbed 2 shifts at the apex. No blipping or anything, just click your downshifts as late as possible. I swear by Silkolene oil too, after tearing it apart each season and seeing how good everything looked.
Just do it! It's lots of fun. The smaller the track the better. You'll have to play around with your gearing to find something that works. I ran 15-16/40-44 on my 2013 YZ450. Looks like it already has a big front brake, but what about the suspension? That'll make a world of difference if it's set up properly.
14/45 is stock.. I’ve got a 15 I’ll put on the front... you think I should go all the way down to a 38? A 42 from that gearing calculator above gives me a top speed on 109 in 5th (5 speed tranny)... I just don’t want it to be a dog on slow speed corners