Help. Rhino carb settings not even close - Page 2

justin1328 · 02-05-2020, 10:28 AM

So another update and quick question. Took my Rhino out yesterday for a quick ride, it was a beautiful 65 F day. Quad was bogging out 1/4 - 3/4 throttle. It was running great on Sunday when it was 40 F outside. I am assuming I am now running too rich. So is this related to the air / mix screw? Should I down size main jet from a 115 to 110? or should I adjust the needle position? up or down? And as always, thanks in advance for the help.

dragonbusa · 02-05-2020, 11:35 AM

No that wont help, its called an idle air mixture screw. Its not going to effect off idle performance.

justin1328 · 02-05-2020, 12:13 PM

Quote:

Originally Posted by dragonbusa

No that wont help, its called an idle air mixture screw. Its not going to effect off idle performance.

So I am not referring to the idle / air screw on the side, but rather the air mixture screw on the bottom, this is a Mikuni clone that has an additional screw on the bottom.

bogieboy · 02-05-2020, 01:03 PM

Quote:

Originally Posted by justin1328

So I am not referring to the idle / air screw on the side, but rather the air mixture screw on the bottom, this is a Mikuni clone that has an additional screw on the bottom.

that is the idle air mix screw. the one on the side is your idle speed screw, which adjusts the height of the slide for idle speed.

justin1328 · 02-05-2020, 02:45 PM

Well, Then I'm learning a thing or two here. Thank you. That said, the idle seems to be fine, so I am guessing its the jetting or the needle position??

Darth Racer · 02-05-2020, 07:38 PM

Check an make sure your choke cable is working the full movement of the clutch... thinking it might not be opening all the way.

Yeah if need be before changing jets try going up or down one notch on the needle and test it out

justin1328 · 02-06-2020, 10:11 AM

Thanks Darth!

Weldangrind · 02-11-2020, 11:59 AM

Quote:

Originally Posted by justin1328

Quad was bogging out 1/4 - 3/4 throttle.

There's the key. Here's a brief summary:

- The slow jet is the basis for idle
- The pilot mixture screw is responsible for the transition from the slow jet to the main circuit. If the pilot mixture screw requires more than two turns out, the slow jet is too small. Ideal adjustment is found when you have a smooth throttle from idle.
- The jet needle in the slide is responsible for mid-range. As you open the throttle, the needle jet (directly above the main jet) is slowly uncovered by the tapered jet needle. Raising or lowering the jet needle affects how quickly or slowly the main jet comes on fully.
- When you're at WOT, it's all main jet in theory. The rest of the story is that the slow jet is still contributing fuel, but that's not important here.

If you move the clip up on the jet needle, you'll lift the slide later, which delays the onset of the main jet (that leans out the mid-range). Move the clip only one groove, reassemble and test; does it get better or worse?

justin1328 · 02-12-2020, 04:57 PM

Weldangrind Thank you. I was aware of some of those principles; however, I have read that some guys swap out jets simply to adjust for ambient temp and altitudes. I am guessing that these guys are hardcore racers and need every ounce of edge they can get..... Not so much for a recreational Rhino

In my case, it was the choke not opening all the way because of the way I had the choke rigged after installing the new carb. Non the less, I certainly learned a thing or two about these carbs in the process, and to me that is half the fun.. Thanks again sir.

02-05-2020, 10:28 AM	#16
justin1328 Join Date: Dec 2019 Location: Somers Point, NJ Posts: 37	So another update and quick question. Took my Rhino out yesterday for a quick ride, it was a beautiful 65 F day. Quad was bogging out 1/4 - 3/4 throttle. It was running great on Sunday when it was 40 F outside. I am assuming I am now running too rich. So is this related to the air / mix screw? Should I down size main jet from a 115 to 110? or should I adjust the needle position? up or down? And as always, thanks in advance for the help.
	0

02-05-2020, 11:35 AM	#17
dragonbusa Join Date: Dec 2019 Posts: 28	No that wont help, its called an idle air mixture screw. Its not going to effect off idle performance.
	0

02-05-2020, 02:45 PM	#20
justin1328 Join Date: Dec 2019 Location: Somers Point, NJ Posts: 37	Well, Then I'm learning a thing or two here. Thank you. That said, the idle seems to be fine, so I am guessing its the jetting or the needle position??
	1

02-05-2020, 07:38 PM	#21
Darth Racer Join Date: Apr 2016 Location: MD Posts: 558	Check an make sure your choke cable is working the full movement of the clutch... thinking it might not be opening all the way. Yeah if need be before changing jets try going up or down one notch on the needle and test it out
	0

02-06-2020, 10:11 AM	#22
justin1328 Join Date: Dec 2019 Location: Somers Point, NJ Posts: 37	Thanks Darth!
	0

02-12-2020, 04:57 PM	#24
justin1328 Join Date: Dec 2019 Location: Somers Point, NJ Posts: 37	Weldangrind Thank you. I was aware of some of those principles; however, I have read that some guys swap out jets simply to adjust for ambient temp and altitudes. I am guessing that these guys are hardcore racers and need every ounce of edge they can get..... Not so much for a recreational Rhino In my case, it was the choke not opening all the way because of the way I had the choke rigged after installing the new carb. Non the less, I certainly learned a thing or two about these carbs in the process, and to me that is half the fun.. Thanks again sir.
	2