Can the RMZ250 be GOOD? Porting, cams, GET ECU Dyno tested 

While JGR's success was very limited, I do agree the platform is capable. I would have imagined JGR would have added their own estart - but never happened.

@@HPRaceDevelopment yeah, that was really puzzling to me as well.

Yes we offer mods for that too.

yep. where do you think 2021-22 head and cam updates came from?

@@HPRaceDevelopment Full GYTR Kit is not only head and cam. There is a HC piston, a pipe end a ECU with a good tune. Anyway...all is very interesting....How many HP is a full GYTR Kit on a 2022 YZ 250 F ?

@@giovannicastignani524 We have dyno the current version in its full sales config. Its not too great. As stated, in 2020 where do you think Yamaha production bike team got their specs for the new head, cam, and piston design, ecu settings, that came stock and updated for 2021? You act like Yamaha r&d isnt smarter, more well funded, better equipped, and better staffed than any aftermarket. Who designs and develops the gytr products? and who at Yamaha signs off on approval for official Yamaha branding, retailing through Yamaha? The fact is - the production yz250f has closely followed the gytr product line up about every 3 years.

I think you'd be sorely disappointed...while the factory bikes are as good as a 250 can be - just listen to the reviews of those that have ridden them. Pat faster rode the star bike and didn't just rave it was 450 power. Keefer and steve mathes rode the gieco bike and didn't rave about the power. I can't disclose all we test and all we see - but I have gotten to compare out pacakages against factory packages on the dyno. At the end of the day there are no secrets, and they dont last long... I can assure you the star bike is no more than 2 hp better than any other bike. I didn't comment where our base map for this rmz came from - but it's safe to say the power production of this rmz is within 3-4 percent that of the full race effort - and that package was clearly close in performance at redbud to the star bike. In other racing disciplines - IE road race - aftermarket has solidly gotten huge numbers for a long time. The cam, valve, piston tech is all available for motocross.

@@HPRaceDevelopment I'd believe you, except for 2 things. Yamaha doesn't fill the first corner for their good looks, and some insider sources have confirmed they have at least a 5 HP advantage. Jett has claimed 7. We all know HP is just an imaginary number and the torque curve really tells the tale, but Star results are pretty indisputable. With unlimited fuel options any bike can be made to work, but given the AMA limits I thing the STAR intake tract rules. With the extra rotating mass, clearly the Yamaha arrangement in the 450 class doesn't work.

@@mxaniac you can't fake science. Where do you feel their advantage lies mechanically? I HAVE inside sources - and while it's not fair of me to disclose the details - I can assure you they do NOT have a 5 hp advantage. Go back and watch - The geico bikes were up front a lot of starts. So were the PC bikes. I watched at thundervalley in person at the start the PC bike pull dead even up the hill next to star bike. Star happens to have an army of featherweights too - ferrandis had terrible starts all year - likely their heaviest rider. What star DOES have is extreme RPM. There lies a lot of advantages in this if you can hold the power you have all the way to the end. Other teams do too - but the star bike at the national level revs around 16500 reliably. The head isn't as special as people think being "backwards". And the bucket cam design is by far the WORST option. Even yamaha superbikes have gone finger follower - and you can expect the yzf to go this route next generation. I would say they have about a 1 lb ft advantage at the right rpm where the riders like it.

@@mxaniac we will have more videos in teh future with extremely cool info. Our current ktm on that dyno scale will go about 46.

Is that the max you can squeeze out of the Rmz,? I wonder how my power my Ron Hamp race heads, with webs cams over size buckets, upgraded valve train,twisted vortex ecu mapped on pro 6 makes

In the video you can see side panels removed vs on - and we dyno with seat off and on - which is most air you can get no real difference. For the most part - other than a louder bike noise there isnt much with the opening the air box a lot. Even the later jgr 250 didnt have the swiss cheese air box - mostly stock inlet area.

@@HPRaceDevelopment Ya, I see the plates on in this video, and I watched the vids where you where trying different intake things....I have noticed in some JGR pics that the plates were looking pretty stock like you mention. Did you trim the intake chutes any for this video and were you running the twin air screenless cage and "knobby" filter? Thanks for your help!

@@michaelkeating1480 I have a video where I test with no air filter at all, no cage, screened cage no filter etc. The point if you watch should be quite obvious. There isnt' much power to be had....The gains that are "said to be there" are not.

@@HPRaceDevelopment Thanks!

They do on their 250. The 450 uses showa

We have found "normal" car style thinking on the high end 4 valve engines doesn't work.

ktm was stock as shown - and the ecu and pipe version didnt loose any bottom from std.

@@HPRaceDevelopment I gotcha. I was looking at 5:48 vs 5:58 and at 7k it looked just a hair lower than the rmz on the second run compared to the first. I don't know much about dyno runs though, that could be within margin of error or something.

@@nepicness Different days on the two ktms compared. The ktm isn't modified mechanically - its just tuned and pipe from twisted.

2500 ish

magazines are a lot of bullshit. but the rmz is certainly the slowest stock 250 currently sold. doesnt mean its bad

Yes, email me, harrisperformance@gmail.com

Email me, harrisperformance@gmail.com so I can give you a detailed break down

Thats generically a good starting point. When you deep dive this a little more - you will find that each fuels stoich afr isnt 14.7 which means the true afr isnt 12.5 for various fuels - rather the lamda reading is approx .86. if a fuel has a stoich of 13.8 - lamda .86 would be in the 11s of true air fuel ratio but shops dont recalibrate their scale and report 12.5 even though its incorrect to the fuel

about 3k on a good condition engine that doesnt need low end work

True. Then dump 10k into suspension!