ONE CYLINDER, HELP?!

[Rush600guy]

So... Acquired a 2010 Polaris Rush Pro R 600 with bad crank, got a 2012 motor sent up here to remote AK. Did the swap, new SPI pistons & one cylinder was bad, compression tested it to 50-90psi, other cyl 120... sent the bad one to Darby's Performance in Fairbanks who returned me a used/honed cylinder @ 100psi. $280 later - Terrible service, no offense to anyone.
Now... my new/bad 100psi cylinder runs and my good 120psi cylinder doesn't... wtf?
all electronics are upgraded except for TPS (waiting on 5v parts to reset) & ECU. adjusted the throttle cable last night, switched fuel relay back n forth, got spark, fuel, oil, and air.
When I start it it idles at 1400rpm +-200, 32*f+ it idles up to 2400rpm and boggs down if I WOT
Any ideas and/or experience would be greatly appreciated, please help.

 

[NapaMatt]

Did you go with new injectors too??

New fuel filter?

With a "New" Engine ... You should be getting 125psi IN Both Holes!! not 100 in one and 125 in the other.. Not going to run well or long that way

 

[Rush600guy]

yeah it was a used motor w/ 2k miles. was a lemon, bad cyl, got a $250 refund, switched out my core cyl for remanned (100psi max, called the shop back w no good customer service).
switched from 2010 4 injector to a 2012 dual injector (just cleaned em), new fuel filter SPI, and ECU is 2012.
running 50:1 for motor break in while oil line bubbles clear, gonna try to thin that ratio down with some fresh fuel. Spark plugs new but very wet. might even switch the injectors around just to make sure the dead cylinder doesnt follow, ie bad injector. if injectors are good I would like to say maybe the TPS sensor needs tune?
just odd that my (old) good 120psi cyl is the bad cyl now, and my 100 psi cyl is the current power house.
Any input or ideas?

 

[Rush600guy]

I'll get a new cyl asap (payday) but when I talked to the shop he said he stands by his product, that its my pistons (brand new). Naw, he overbored it past spec. Anyways, only thing he can do is let me send it back and make me pay the extra $100 for a rechromed 125psi. just sucks cuz I helicoiled my fuel rail inlet and living where I do is expensive to fly a cyl from nome to fairbanks. $30 each way and still takes a week turn around.

 

[Rush600guy]

Napamatt
funny enough I work there too

 

[NapaMatt]

haaha

Small World!!

Getting back to 125 psi.. is what u need!!

 

[NapaMatt]

Also..


Whats ur fuel pressure..

Maybe thats why is was lean in the first place.. and went down.. hmm

 

[Rush600guy]

Yeah a 125psi cyl would be 100% primal, was my goal but I got shafted and now, naturally I'm skeptical when it comes to his new deal with a re-chrome for $100 more w trade and $60 shipping. I hope he likes a nice helicoil job lol, stronger threads.
Far as I know my new fuel system hasn't been this good since factory, starts 2nd pull (even on 1 cyl). Unfortunately, I don't have a fuel pressure gauge... though I could prolly make one for cheap.

 

[NapaMatt]

and ur reeds are good.. an the intake boot?

 

[Rush600guy]

Yeah reeds are brand new Mototassinari 3r's and the intake boot looked fine last time I checked... prolly check again here soon, atleast when I get paid and pull the cylinder off - hopefully for the last time.
I'll prolly change out and dilute the gas/oil mix tonight, make sure the 50:1 gas + (sparse/bubbled) oil injection isn't too rich for that cylinder's spark plug. Brand new bpr9es's get pretty wet pretty fast.

 

[NapaMatt]

did u ever test the injector with a 9 volt battery.. to see if its a Spray VS a stream?

 

[Rush600guy]

Not with a 9v, but I did it with a 12v by tapping the circuit's power on the battery terminal, method: https://www.youtube.com/watch?v=rUUgR94drxg
3m brake cleaner p/n 08880
Electronically both worked great, bad stream at first but now they're clean AF & both spray vapor.
I can say I neglected the 3v difference, but I'm pretty confident I didn't over strain the solenoids.

 

[NapaMatt]

see if you can get a fuel pressure gauge...

will tell you alot about ur fuel pump!!

 

[Rush600guy]

Been going through my manual... "Troubleshooting/ENG Starts - Won't Idle/Stalls" page 4.54 it asks,
"Is the eng mechanically sound? Perform a compression check on both cylinders. Are the results within 10% of each other?"

MAG 120psi x 0.10%= 12psi MAX Allowed Difference
PTO 100psi
-------------
20psi/18-20% Real Difference


... Gotta be my (Remanned) PTO cylinder being bad, just cant fathom why my PTO is the power cylinder and MAG is bad... hope the PTO isn't shocking the crank every time it fires (perhaps early).

 

[Rush600guy]

new fuel pump also... but I will check my fuel pressure and annotate it here soon

 

[NapaMatt]

yes.. you need 125 psi.. in each hole

 

[Rush600guy]

Pulled the cylinder and measured the bore, Polaris Manual specifies a bore limit of .002" or .051mm.
Measurements:

OEM 77. 25mm

Top: X 77.1144. Y 77.1779
Over by 0.1356. 0.0721

Middle: X 77.1271 Y 77.1779
Over by 0.1229.

Bottom: X 77.2033 Y 77.2287
Over by 0.0467. 0.0213

Fortunately now that I have the math of this over-hone the owner of Fairbanks Darby's (where I got the cylinder) is now willing to work with me. Might get free shipping and a new rechrome cylinder.

 

[diamonddave]

SPI pistons for the 800CFI are junk.

 

[Rush600guy]

OK Welp... Got some Pro X pistons (originally planned for Wisecos but the shop never shipped em out and, yeah), two new cylinders, and holding 130psi in each. Running on two cylinders thank God.
BUT, Det code still shows, and it idled a couple healthy times, but bogged and died with throttle. Since then I've prolly ripped the cord a few hundred times with no start... without a code reader I'm thinking the TPS sensor is the fault, what would you guys think?
Everything is plugged in...