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Discussion Starter #1
I have an 06 660, what is the procedure for adjusting the A/F ratio? Do you have to remove the carb to get to the adjustment screw? (I have an A/F gauge that is showing about 14 as an average)
 

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You do need to remove it and unplug it the first time. After that it's possible to use a small screwdriver if you fit it under.

 

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I have always had to remove the carb to do this as i cannot fit a screw driver and my finger under the carb. I wish someone would make a needle with a thumb screw on it.:dunno:
 

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How often do you really need to change the idle mixture? Shouldnt be that much...I haven't touched mine in almost 2 years. The main jet on the other hand I change about 3-4 times a year when I go to high country.
 

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Discussion Starter #8
You do need to remove it and unplug it the first time. After that it's possible to use a small screwdriver if you fit it under.

Chandler, I have set the A/F ratio and changed fuel filter but still having problems with acceleration. When you put the peddle to the floor the Rhino struggles to get moving until the tach hits about 5000 rpm, and then its not a real fast take off. Top speed is about 40 mph and I have a Hunterworks CDI that eliminates the stock top end. There is about 45 hours on this machine and it did not act like this when I purchased. Any clues on what to look for?
 

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Are you saying your stock rhino runs like a fat old dog but used to run like a jack rabbit.... :)

j/k...

Tune your wot throttle with the mainjet first for around 13.5:1

Set your idle a/f at about 12.5:1

Select the pilot jet that allows you to get that 12/12.5:1 idle a/f with around 2.0 to 2.5 turns out of the screw...expect that to be a 45/50 ymmv...so you are going to fatten your idle a bunch with a bigger pilot jet...then lean is some with the idle screw...if you have to go more than 2.5 turns out to get to 12:1 idle a/f your pilot jet is too big...

Then measure your e/t's in a fixed distance.... 0-300' works well...

Adjust your needle height for max accleration...lowest e/t's

Then fine tune your all four best launch and lowest e/t's...

You should also make sure you have an high flow air intake...

Also select your CVT secondary spring for best overall performance...

Unless you have compression problems or something you should be able to get it to run better/faster than it did before....
 

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have you cleaned your filter since new? May be clogged air filter, may need a new fuel filter or you may need to adjust the valves if that was never done. Check you accelerator cable and make sure wide open is a flat butterfly with the least restriction.

What O2 reading are you getting?
 

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Are you saying your stock rhino runs like a fat old dog but used to run like a jack rabbit.... :)

j/k...

Tune your wot throttle with the mainjet first for around 13.5:1

Set your idle a/f at about 12.5:1

Select the pilot jet that allows you to get that 12/12.5:1 idle a/f with around 2.0 to 2.5 turns out of the screw...expect that to be a 45/50 ymmv...so you are going to fatten your idle a bunch with a bigger pilot jet...then lean is some with the idle screw...if you have to go more than 2.5 turns out to get to 12:1 idle a/f your pilot jet is too big...

Then measure your e/t's in a fixed distance.... 0-300' works well...

Adjust your needle height for max accleration...lowest e/t's

Then fine tune all five elements (mainjet, needle postition, pilot jet, a/f setting and idle speed) to get the best launch and lowest e/t's...

You should also make sure you have an high flow air intake...

Also select your CVT secondary spring for best overall performance...

Unless you have compression problems or something you should be able to get it to run better/faster than it did before...

Sorry I went to clean up some typos and hit the quote instead of edit... :brick:
 

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Discussion Starter #12 (Edited)
Are you saying your stock rhino runs like a fat old dog but used to run like a jack rabbit.... :)

j/k...

Tune your wot throttle with the mainjet first for around 13.5:1

Set your idle a/f at about 12.5:1

Select the pilot jet that allows you to get that 12/12.5:1 idle a/f with around 2.0 to 2.5 turns out of the screw...expect that to be a 45/50 ymmv...so you are going to fatten your idle a bunch with a bigger pilot jet...then lean is some with the idle screw...if you have to go more than 2.5 turns out to get to 12:1 idle a/f your pilot jet is too big...

Then measure your e/t's in a fixed distance.... 0-300' works well...

Adjust your needle height for max accleration...lowest e/t's

Then fine tune your all four best launch and lowest e/t's...

You should also make sure you have an high flow air intake...

Also select your CVT secondary spring for best overall performance...

Unless you have compression problems or something you should be able to get it to run better/faster than it did before....
I have not adjusted the valves, but the air filter is clean and I just replaced the fuel filter. It does also have a Hunterworks performance sheeve installed with an aftermarket belt that has maybe 30 hours on it. This Rhino used to run great but can't pull itself up a hill without putting it in low gear now. Very frustrating.

have you cleaned your filter since new? May be clogged air filter, may need a new fuel filter or you may need to adjust the valves if that was never done. Check you accelerator cable and make sure wide open is a flat butterfly with the least restriction.

What O2 reading are you getting?
Chandler, I don't have a way to measure the 02, only the A/F which is about 13 at idle. I have not adjusted the valves, but the air filter is clean and I just replaced the fuel filter. It does also have a Hunterworks performance sheeve installed with an aftermarket belt that has maybe 30 hours on it. This Rhino used to run great but can't pull itself up a hill without putting it in low gear now. Very frustrating.
 

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TYRAP
How did you come up with 12:5 for the idle A/F ? It seems to be well into the fat range. I just started tuning today and was shooting to get all circuits in the 13 range.

45 pilot
3/4 out on the screw
Dj needle on #2
150 DJ Main
Mods DG pipe single, UNI air filter in stock box with lid on snork removed
altitude 600 and 45* TEMP
 

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Trial and error...

If your desired idle a/f is achieved at 3/4 turns out of the a/f screw your pilot jet is too small...

When you CW to seat screw it cuts off air to make a/f richer...

Inrease pilot to 50 so that you have more turns out to get what you want....

Stock carb...???

I would intall something around 90 starter jet for your fuel enrichment...

Use the pilot jet to establish desired a/f at 1.5 to 2.5 turns out...

The stock carb has no accelerator...too lean a pilot and idle a/f setting gives you lean stumble when you crack the throttle...

Tune for best e/t's in fixed distance with little or no stumble...

Don't use an arbitrary number on your afr gauge...find out what the numbers are on your afr gauge when it runs peak...then in the future use those numbers as a starting place...
 

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I have a older Innovate motorsports LM1 I used it to tune my Yamaha roadstar.
There is really good write up by Ken Sexton about card tuning on the front page of the roadstar riders forum.
If I knew how I would post a link

The sensor next to the screw is a carb fuel heater to help with "carb ice"

FROM TYRAP "If your desired idle a/f is achieved at 3/4 turns out of the a/f screw your pilot jet is too small...
When you CW to seat screw it cuts off air to make a/f richer..."

I think Screwing in the A/F(primary fuel metering circuit or PMS) to lean up.
 

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What A/F gauge is everyone using?
Chandler, what's that sensor for next to the a/f screw?
I have the autometer.... http://www.autometer.com/cat_gaugedetail.aspx?gid=3605&sid=7

I hear the AEN (?) is also a good unit for less...

Yes it's a fuel warmer to prevent icing...which I am told can occur at +70F but other than that.... :dunno:

I think Screwing in the A/F(primary fuel metering circuit or PMS) to lean up.
So are you saying that the LM1 told you to CW from the factory setting to 3/4 turns out to lean the idle a/f to 13:1 from X_rich...

IMO 13:1 is a bit lean for idle a/f especially in colder temps...

I am saying if you CCW the a/f screw it will allow more air to the idle circuit and lean your idle a/f...but the meter will tell you if I have it backwards...it wouldn't be the first time my memory is 180* out from what I actually did...

I am also saying that if you adjusted the a/f screw CW to 3/4 turns out that is not in the good range...and that if you go back out to 2 turns out your idle a/f will be way lean (for best operation but prolly not into the danger zone)...and that means your pilot jet is too small for best overall operation...

I run a 50/55 pilot jet with stock carb and 55/60 with bored stock carb...
 
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