Any RX1 Carburetor Vacuum Spring Mod Sets Around?

[GT Mills]

Any RX1 Carburetor Vacuum Chamber Spring Modification Sets Around?

 

[maim]

for running stock air box or pod filters? with stock air box, you run the green springs. with k+n filters or pod filters, you need to run the yellow ones. i used the holtzman ones when i did rx's in the past.

 

[GT Mills]

Thank you! Holtzman was what I was looking for, lost track of the name/web site address.

 

[RobX-1]

I have the ECP Kit on my RX-1 that used K&N filters along with the Holtzman springs and 165 main jets but this chart is what came with my CV slide springs:

 

[GT Mills]

I have the ECP Kit on my RX-1 that used K&N filters along with the Holtzman springs and 165 main jets but this chart is what came with my CV slide springs:

View attachment 168509

What is ECP?

 

[maim]

it was a kit that put a filter on each carb.

 

[RobX-1]

What is ECP?

ECP (Eastern Cycle Performance) was owned by Freddie Klies (RIP) who came up with a filter kit for the RX-1 that used a combination of K&N filters (two oval shaped filters that encompassed two carbs), larger main jets (#165), and different CV springs (less spring pressure) in place of the stock air box. Some guys also installed a filter for the crank case but guys like myself vented the filters and connected back to the stock crank case vent. I routed the tubing to the stock catch can to go under my filters but here's a picture that shows the setup:

 

[GT Mills]

Ah, I've seen setups like this on other aircraft conversions, I always thought it would lead to mid-range power loss due to improper Helmholtz wave disruption at the intake valve seats. I figured though it may prove WOT improvements on a dyno for a flat-out ice drag race, in practical, real-world use at 75-80% throttle on aircraft it would be a loser. These are just my thoughts, please, and though I have been flying an RX1 (first successful Yamaha Genesis 4-cyl (YG4) aircraft conversion in the world, Nov 2012) for 10 years I am only now bothering to take the time/$$$/trouble to test, tweek and squeeze more power out of the RX1 on my own gyrocopter. Just ordered an Innovative A/F mix meter off Summit yesterday.

This is the world's first successful YG4 conversion. Another fellow tried 2010-2011 with an Apex, but he started with a basic engine and ancillaries, not a sled, no intake box or exhaust beyond the stubbies. He spent over a year trying to convert it before he even got it running on his RFD Dominator gyrocopter, was tearing his hair out of his head by that time trying to figure out the wiring. He never got it sorted out, the damn thing woudl go into limp mode in flight all the time. On top of that he stuck the four stubbies straight into a silencer can/collector, total length of exhaust header was all of about 5". His intake was a hexogon can on its side, same arrangement as the exhaust in reverse. He tried to tell everyone the YG4 was junk, had terrible throttle response/lag, and he never tried to do another one. He spent three years trying to sort it out, never got it right.

This build, attached, is the one I put together 4 months, it was perfect right out of the shop and trouble-free for 10 years. As you can see I kept the stock intake and headers, I shortened the straight pipes to account for the added length through the 90° bend after the flange. to maintain 21" length to the 4x2 collector crotches.

I found that a cross wind created either a low pressure or high pressure under the intake plenum, depending on which direction it was coming from. To fix that I closed off the stock intake tube opening and cut a new inlet on the outer-most flat of the underside of the box. That helped a lot, where before I was seeing +/- 500 RPM oscillations due to cross winds this cut it down to +/- 100 RPM, barely noticeable but still I wanted better so I added an RX1/Apex plastic tailpipe cover as and intake scoop to block crosswinds this spring. (Notice the plastic RX1 tailpipe cover used to cover the PTO driveshaft on top of the engine, the thingy that pre-rotates the rotor blades for take off.)

Well, give a mouse a cookie...Now I need to adjust jetting and springs. Oh, well.

Hope you sledders don't mind too much me cannibalizing your beautiful rides to take to the air! Since I built this first one, there are some 100 airborne YG4's, mostly Apex but lots of older RX1's. Want to know the truth? Not ONE, single, solitary forced landing has been reported due to engine failure!!! It is absolutely the most reliable, the lightest weight, the best fuel burn, and the most HP of ANY aircraft engine anywhere, by anyone, period, end of story, tell ROtax to stcik it where the sun dont' shine TYVM.

All the nay-sayers with Rotax tattooed to their butts said, "Just wait a while, we'll see all these high-revving Yammies take a dump soon enough.

Well, I and we have proved them all wrong, wrong, and wrong. I have customers approaching 1000 hrs this season, while our fleet has accumulated well beyond 15,000 hrs. Multiply that by 55 for odometer sled miles and that is 55,000 miles on a single engine running at 8,000-8500 RPM constantly, for hours on end without a break. Rotax 912 100HP weighs 165 lbs installed, costing $25,000+. A rebuild at 1200 hrs costs $10,000. Used engines run $15,000.

We have been buying used YG4's for anything from $800 - $5000 for ten years now. They weigh 165# installed and produce 140-165HP. The very best stock Rotax turbo is 115 HP, maybe 130 for about 5 minutes before it grenades, and weighs much more, 185 lbs. burning 6-8 GPH at 120 HP while YG4 burns 4.5 GPH at 120HP.

2017 my business Mohawk Aero Corps (MAC) built and started selling the first successful Apex conversions in 2017, the prototype went on a Highlander STOL that flew to Oshkosh in 2018 and won every STOL race event there, something never done before or since to the best of my knowledge.

2019 MAC built and flew the first successful EXUP 165HP aircraft conversion, again on a gyrocopter. It STILL only weighed 165# all-up! Same year, after half a dozen other guys attempted and failed to convert a Phazer YG2, MAC fabricated the first successful kit and our customer installed it on his Quicksilver float plane.

On the one hand I feel bad cannibalizing beautiful sleds for engines, but hey - they are frikkin AWESOME, how can I NOT fly these wonderful beasties?

My website is www.MohawkAero.com, my email is info@mohawkaerocraft.com, so look me up and when you're in town I'll take you flying in the totally rockin' MAC Air Command YG4, a ride I can guarantee you'll never forget.

THANK YOU ALL for this fantastic forum, it is a HU_U_U_UGE source of info!!! You guys frikkin' ROCK!!!