Fixing the YZ85: Dyno Test of Porting and Mods
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- čas přidán 11. 03. 2023
- Yz85 porting, carb boring and jetting, along with head modifications all tested shown on our dyno.
The yz85 is no longer the king of the class vs the ktm, husky, gasgas 85cc. Can we fix that and bring the yz85 into a modern package?
www.hpracedevelopment.com - Zábava
Looking forward to the TM85-mx you showed in an earlier video 👍 keep up the good work!!!
Good looking bikes!!
Do you do bike ups man where are u located
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.
agreed. I truly believe the japenese no longer have the 2 stroke talent to do it. All their knowledge acquired is walking on a golf course somewhere.
@@HPRaceDevelopment more likely the japs are just not interested in 2 stroke development...
@@HPRaceDevelopment very true. And quite a sad realisation if I’m honest. I grew up on the Japanese brands and even to this day struggle to gel with the Austrian bikes, something about the way they feel.
Current Yamaha two stroke engineers need to look at what their past colleagues were doing on the GP bikes of yesteryear. The last gen of TZ125 and TZ250 should be a good starting point…
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.
Please test a kx85🙏
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?
No real opinion. Motocrossers seem to choose the ktm
I think the yz is competitive
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?
You probabky would need to lengthen it
@@HPRaceDevelopment oh? i thought shorter distance to the cone meant peak power at higher rpm
@@tejdz1337 Yes but a full redesign would likely be required. Since you raised the ex, your pipe is no longer in tune with your port. The ex wave is leaving earlier and returning earlier - making the pipe already work at a higher rpm.
A longer pipe would likely bring the tune up back in line with your goals
@@HPRaceDevelopment youre right, i forgot exhaust duration affects pipe timing. might get away with some "torque spacers". thanks for the help
i have big chamber on my kr150 its good for high rpm but give big drop powerband around 7 8k rpm before power valve open, how to get rid that problem
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.
What are you asking me specifically?
It’s the rider not the horse.
The best rider will be faster on the best horse
Fr thats what I was going to say
What gear do you do dyno pulls in?
You noticed that 3 rd gear. Bet power would be way less in 5 than gear .that's what gear most people dyno in not 6 th gear
i only prefer the yamahas because of its the best suspension
How close is the crank hp compared to wheel hp on the dyno?
without a crankshaft dyno - you can never know
Well hmm , always heard the fmf pipe were more bottom end focused.
never heard that
That’s what WTT said.
The eye test on a yz65 it seems like the fmf helped bottom forsure. But Maybe wrong there also ?
Can you make the yz85 match front side of ktm ? If that peak isn’t as important ?
Some yt channel was touting dimples on the piston like a golfball I'd like to see that
On the skirts it can help oil retention but not power.
Not on the crown?.. would I want dimples on the exhaust side of the skirt or all around
The crown would be a disaster for detonation. The skirts wont help power.@@matthewfredrickmfkrz1934
@HPRaceDevelopment just flirting with ideas to try on a honda spree over the winter oil retention seems like it'd help with extensive wot duration
Stupid question. YZ85cc really picked up the pace. Yes absolutely 100% yz85 are competitive. My son is winning almost every race with yz85
You are winning loretta's! Nice!
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?
wheel, and a tad on the low side. I have another dyno that is a load cell that reads a good bit higher.
Yamaha could have easily studied ktm and said - that's smart! Or taken a few ideas. Im told all their two stroke brain power is on golf courses now...
KTM’s trackside R&D experimentation is unprecidented. This is why.
@@GR40RCapri Yamaha was formerly a 2 stroke powerhouse from about 96-06
Their trackside feel and power character placing them ahead of “faster” engines of the time. That said their current staff clearly hasnt evolved or learned from developments since about 99. shame
@@HPRaceDevelopment great interview w/ Grant Langston during the uprising of KTM after the buyout. :
czcams.com/video/p9dXOxae1og/video.html
I had a 95 yz80 as teen with an FMF on it and remember it pulled like a freight train. As an adult I wondered if I just hard rose colored glasses and got the chance to ride one same year same bike and it was still a rocket! This is with me riding all the various current stuff. So that makes me wonder, is that 95 motor stronger than the current yz85? Is the port design actually better?
23 peak hp @12,500rpm and signs off to 15hp @13,500rpm and kids are revving to 16k? Shift!
yes. Riders are dumb in how they ride but its what it is.
two tenths (0.2) of a millimeter?
what
you mention the dimension was alter by 0.2 were they millimeters or ich?@@HPRaceDevelopment
.002" is too tight to measure for me in porting
.2mm @@alejandroesteves8903
Should have left it stock. All that work costs money and reliability. For 2 hp gain.
2 hp?
What you talking about willis
Both bikes went 50 hours each, no headaches and sold to next client. for 15 percent gains - 3- and nearly 4 hp - it's quite a nice improvement.
2 hp is much on this 85 2 stroke
I just want to find a good cylinder for my bike that’s not 500 dollars😭