a very nice brc500 ride report here from ktmtalk
Brc 500
- Thread starter steve250f@hotmail.com
- Start date
well.............somebody out there must be puting one of these engines together ? They had sold out of several production runs of engines according to their website/road test conversations.
I read the ride report and posts from KTMTALK.All the talk about gearing 12-54 still doesn't make sense to me. They say it is to fix the soft bottom end power. It sounds like its good for old guys who like to ride 500s on trails is all I got out of it. I hope it has more potential.
Looks like a work in progress, EFi with a get ECU right away to have full control of ignition and fuel would have made tuning easier. Even then it will still be a huge amount of testing to get it right. Gearing seems to be a issue due to the primary re gearing on the crank. Recluse an counterbalances act like extra flywheel weight softening up the bottom end further no surprise there. The power potential is still the same as a cr500 but that one has 45 years of refinement and testing under its belt and still is just a cr 500.
The primary gear ratio had to be changed by BRC in order to make it a drop-in kit using KTM 250/300 internals/chassis. If you use stock 250/300 sprockets you'll have a dirt bike that has a softer bottom and a top speed of 140mph.
If I recall correctly, BRC's first engineering explanations for the kit motor, they changed the gear ratio of the primary drive to transmission/clutch to reduce the stress on the 300 KTM transmisson so it would safely strand the extra power once the kit was developed.
I totally understand why brc made the primary ratio 20% higher. But the engine is twice the displacement, it should be able to handle a much higher gear and not feel soft but they are running them with 12/54 sprockets! The only gain I can see in that is making 1st useless and you basically tighten the gaps between 2nd to 6th. Still seems like a 500 shouldn't need any gearing Band-Aids to make it not seem soft. We all know it's a pretty useless bike for dirt but why aren't they all over the mountains in the winter? I would love to ride one in the snow and see it's true potential. The 4 stroke scene needs some competition. I keep thinking of a few years back with nitro/viper turbos and 1100t sleds were popular, and now 2 strokes are king again in the mountains!
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portgrinder
Well-known member
I really like what these guys are doing but the juice isn't worth the squeeze the way its currently marketed. $7500 is real money, and it doenst make a lot of power. plus it only fits the old chassis.
interestingly enough, we plotted the 300's we built (compression, carb, pipe) against a strong 450 (cyl work, compression, ignition, pipe) and the 300 is a little better. it just doenst have the legs to rev out as far. they are an absolute hoot to ride though.
the panthera is full of issues, bad machining, poorly threaded bolt holes, bolts that are to short and sheer, a Chinese atv starter that's 17 dollars, a bendix that fails and grinds the flywheel gears and case up, an analog stator of a 450x vs a 2000 cr250 digital ignition that idles and starts perfectly... etc. etc... lousy machine work and design.
BRC is class act through and through... very little hiccups on that design and motor functionality. Most of my info comes from MRE racing on both of these topics. (the defacto CR500 expert anywhere) He helped design the BRC cylinder and can take them from 60hp to 75+ If I was building one for a snowbike it would definitely go to him before me to get ported and built for reliable power.
BRC is class act through and through... very little hiccups on that design and motor functionality. Most of my info comes from MRE racing on both of these topics. (the defacto CR500 expert anywhere) He helped design the BRC cylinder and can take them from 60hp to 75+ If I was building one for a snowbike it would definitely go to him before me to get ported and built for reliable power.
one other note... I burn 7+ gallons of fuel on a full day on my cr500. That's the biggest downside to a 2stroke on the snow. 40 pounds of fuel on the tunnel and another 18 in the primary tank is a lot of weight to cart around the first half of the day. I'd personally have a 450 as well if you are going to build a 500 2T.... play bike, big mtn day bike.
My guess as to why they aren't all over the mountains in winter is that the first run of motors was only 50 units and most didn't get out the door until late into the 2018/19 winter. Many of the motors have gone overseas and many of those have gone to Australia specifically. I suspect you'll see a few pop up in the next couple winters but even then, there just aren't that many BRC 500's out there.
Looks like this dude has his BRC 500 running.
8 gallons? My 380 can go all day with 6.
Nice to see it on a Riot! The power band sounds really narrow but that's how 500s roll... never mind that I forgot it has a 6 speed!
Nice to see it on a Riot! The power band sounds really narrow but that's how 500s roll... never mind that I forgot it has a 6 speed!
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portgrinder
Well-known member
My kx5 @ 85 ponies would never use more than 5.5 gal per day. most times a lot less.
Hmm, the numbers they posted in September 2018 were 72hp and 59ftlbs of torque (not tuned by Adam Millar). I just texted Riley and he said with the included FMF pipe they are getting 67hp and 53ftlbs of torque. Their latest numbers with the HYGGE pipe are 76hp and 63ftlbs of torque (not tuned by Adam Millar). He couldn't really comment on the fuel consumption except to say that for him on his dirt bike, the fuel usage is marginally higher than his 300 but that it would largely depend on where and how you ride.
Full disclosure: Riley & I are dirt biking buds and I have known him my entire life. He's not an internet jockey like I am so because I'm excited to see his dream come to life, I take an interest in what's being posted.
They also have a 14-1 head available now. According MRE the STIC in a keihin is the best power option. Im going to run a power cdi with a 38 keihin on my personal bike. There is a lot of mapping left to be done with timing curve etc. TQ #s 60+ is the part that im the most excited about! 80HP isnt a bummer either.
Brc500 mono rail