HPBCANADA.COM • View topic - Lean running 2.6 225 Yamaha

I tried another compression tester and it showed 130psi.

Drilled the needle and seats out .012"

Main jets are drilled to .093" thats .020" over where i started

Electric fuel pump installed and checked pressure at 4.5psi

Still running lean, plugs are white at 4700 rpm. It seems to make a small difference when i drill the main jets. Going another .010" bigger and trying again tomorrow.
Our one and only drag race on the island is this weekend and i want to get this thing screaming. Should i try bigger on the needle and seats as well?

Author:	Jeff Yammer [ July 3rd, 2015, 8:45 am ]
Post subject:	Re: Lean running 2.6 225 Yamaha
110 is a happy easy on a motor for sure. On my 2.6's I ran 145 +/- cold cranking with Shell 91 I have zero experience with any of the Yamaha computer stuff as I ran the basic Yamaha electrics. An electric pump with a reg is insurance for sure or the old stand-by Holley RED pump mounted low with a 100mic pre filter and a 30mic post filter. Hope you get it sorted man.

Author:	DoktorC [ July 3rd, 2015, 8:53 am ]
Post subject:	Re: Lean running 2.6 225 Yamaha
110 is low...is your Guage right? Stock they make 130ish...and it's not insanely ported. It's good but I can't imagine it taking away that much. The block is a Ray N block FYI Jeff.

Author:	Jeff Yammer [ July 3rd, 2015, 10:03 am ]
Post subject:	Re: Lean running 2.6 225 Yamaha
Woooosh if it's ported to go from 130 to 110 .... That's gonna be a nasty piece of business. Keep us informed on your findings. Mr.Cole knows his Yamamas and your electrics.

Author:	J.Kimmerly [ July 3rd, 2015, 12:44 pm ]
Post subject:	Re: Lean running 2.6 225 Yamaha
Thanks for your help guys. I've got a Carter P4070 fuel pump I'm going to wire up today. The compression tester read 125 psi with my stock 225 with those heads I seem to remember but I'll see if there's another gauge around that I can try.

Author:	beavertonae-21 [ July 3rd, 2015, 10:24 pm ]
Post subject:	Re: Lean running 2.6 225 Yamaha
what prop/ rpm are you running?

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Author:	J.Kimmerly [ July 5th, 2015, 3:03 pm ]
Post subject:	Re: Lean running 2.6 225 Yamaha
Im running a worked 27 srx right now. I've got it set up real rich and haven't taken it past 5400rpm. But it is ported to run close to 7000. Had to drill out the needle and seats like Doc suggested and am still setting this thing up.

Author:	J.Kimmerly [ July 6th, 2015, 9:24 pm ]
Post subject:	Re: Lean running 2.6 225 Yamaha
DoktorC wrote: It's probably easier to add fuel through the main jet...how lean is it? If you find bigger jets don't do anything you may need to drill the needle and seats. You are correct about the air jets on the top of the carb. Im having flooding issues since drilling the seats out. Is that just part of the game or have i gone to big? I notice the further up the rubber on the needle the harder it gets. I have a set of un drilled carbs when i hold them upside down get my old lady to blow on the gas line no air gets through. Drilled ones are leakers.

Author:	DoktorC [ July 6th, 2015, 9:31 pm ]
Post subject:	Re: Lean running 2.6 225 Yamaha
You may want to start with fresh needles and make sure the seats don't have a ridge from the drill.

Author:	J.Kimmerly [ July 13th, 2015, 3:26 pm ]
Post subject:	Re: Lean running 2.6 225 Yamaha
I tried another compression tester and it showed 130psi. Drilled the needle and seats out .012" Main jets are drilled to .093" thats .020" over where i started Electric fuel pump installed and checked pressure at 4.5psi Still running lean, plugs are white at 4700 rpm. It seems to make a small difference when i drill the main jets. Going another .010" bigger and trying again tomorrow. Our one and only drag race on the island is this weekend and i want to get this thing screaming. Should i try bigger on the needle and seats as well?

Author:	DoktorC [ July 13th, 2015, 4:16 pm ]
Post subject:	Re: Lean running 2.6 225 Yamaha
J.Kimmerly wrote: I tried another compression tester and it showed 130psi. Drilled the needle and seats out .012" Main jets are drilled to .093" thats .020" over where i started Electric fuel pump installed and checked pressure at 4.5psi Still running lean, plugs are white at 4700 rpm. It seems to make a small difference when i drill the main jets. Going another .010" bigger and trying again tomorrow. Our one and only drag race on the island is this weekend and i want to get this thing screaming. Should i try bigger on the needle and seats as well? I'm sure you're needles and seats are flowing enough if they are any larger than stock. Are you sure there's not an air leak in the motor?

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