Fixing the YZ85: Dyno Test of Porting and Mods 

Looking forward to the TM85-mx you showed in an earlier video 👍 keep up the good work!!!

That's an impressive gain but the reason still remains why most people are keeping their kids on the Austrian brands, strong low end, strong mid and a usable top end makes the bike a lot easier to ride and go fast on, get the mid pack and back riders loyal to your brand and you're selling three times as many bikes. I'd love to see another manufacturer contest and push development of small bore 2strokes on, that just means more choice and better bike prices.

Good looking bikes!!

Yo, new to visiting your Channel- very Rad vid 😎 Makes me feel less buyers remorse😅 on the yz85 we just picked up for my 11 yr old (2003) I was almost going to spend a bit more On a YPVS (2019+ YZ85) as I expected more low & midrange as I have been told. Your Dyno shows neither, if I’m seeing correctly! 😯) Was just freshened top to bottom with many new parts and spares.built for his own son. Cylinder mods are planned- Lathe & foredom in-house 😊. Lots of small bore Cyl experience porting… just don’t know what direction to go yet… 🤔🤔🤔 Subbed & shared.

It’s the rider not the horse.

What are you seeing from the Athena kits on these ? I know you had to figure out how to make them work. So I imagine yours are the best right now.

Do you sell complete ready to go cylinders or offer porting services?

Stupid question. YZ85cc really picked up the pace. Yes absolutely 100% yz85 are competitive. My son is winning almost every race with yz85

Well hmm , always heard the fmf pipe were more bottom end focused.

Hey Derek. Not exactly YZ 85 related, but I’m looking at getting a 65cc bike for mini supermoto. It will be used in a competitive class, so looking for the best option. May be used for a 24 HR endurance race. KTM65 vs YZ65? Will be adult ridden. Do you have a recommendation?

Please test a kx85🙏

The japanese engineers seems to be thinking for a long time before they go to the R&D, as the 125 took Yamaha 18 years to redesign the engine package? Meanwhile KTM is progressive- no intermediator bureaucracy. One likely reason is that the mx branch of the japanese buisness is just a small slice of the brands massive "portfolio",or in laymans term KTM does not overthink they just do it. But i still scratch my head and wonder why the japanese brands are willing to give up the supermini market to KTM 🧐. But hey obviously you can tweak both the yz and kx to be competitive as shown here by HP. Btw is everything on this dyno to the wheel or to the crank?

i only prefer the yamahas because of its the best suspension

How close is the crank hp compared to wheel hp on the dyno?

Some yt channel was touting dimples on the piston like a golfball I'd like to see that

Do you do bike ups man where are u located

how far can raise exhaust port roughly speaking before the expansion chamber will become unefficient or not work well anymore? i modified a KX60(as recommended by a KX60 tuning guide) by raising exhaust port about a millimeter, but it felt like i lost peak horsepower and only gained a rediculous amount of overrev and a broader powerband (and ofc all bottom end is gone). should i shorten the expansion chamber slightly to gain more peak?

DO people run the 85 bottom end with 65 barrel? Im sure ive seen some cheater bikes like this.

What gear do you do dyno pulls in?

Should have left it stock. All that work costs money and reliability. For 2 hp gain.

23 peak hp @12,500rpm and signs off to 15hp @13,500rpm and kids are revving to 16k? Shift!

two tenths (0.2) of a millimeter?

I just want to find a good cylinder for my bike that’s not 500 dollars😭