Hello,
I have a 2005 and 2004 eton which I removed the Oil Injection systems from. They are the same except for the stock carb setting. I raised the main jet needle on the 2005 to the bottom setting and it has been running great. The 04 I did not have as many notches to adjust but I went to the lowest one and the quad ran good but had less power than normal. It would not go up small step hill. It would die at the top and roll down. So then I went from the stock 85 main jet to a 95. Not much difference so then put three very small #4 brass washers under the needle clip to raise it more and not much difference. The quad runs well but my daughter tells me past 1/2 throttle it does not really go anywhere. Just cruises up to top speed. I just ordered a 100, 105 and a 110 main jet thinking it is just not getting enough fuel thru the main jet for high speed operation. Suggestions? Very frustrating because the quad is running great with the exception of the loss of top end power.

 

Switch carbs from one to the other and see what happens.

 

Thanks LT80. I am going to give one last shot at cleaning the carb based on the reply I found below to another person issue. I did not know the needle jet came out of this carb so I did not specifically clean it. If that does not work I will drop the needle and carb from one atv to the other and at least confirm the carb is the issue.
I have posted the content of the other board question I came across hopefully someone might find it useful. I will keep you posted

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QUESTION: I am trying to figure out if I have a rich or a lean main jet. At about 3/4 throttle it bogs down and loses power. It runs fine in any other throttle range. I've run a plug chop and it looked white so I figured it was lean.
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RESPONSE:
For the symptoms you are describing,,,,

Try Raising the jet Needle by lowering the clip.

If 1 or2 position changes dont do the trick,,
You very possibly have a problem somewhere.
Such as an Air Leak in the intake manifold system/cylider base gasket/crank seals,,etc,

or perhaps partial clogging of the needle jet.

It it starts Ok,,,and idle is stable,, that pretty well eliminates air leak possibilities .

Needle adjustment----is a LARGE increment.
Much more influence than the tiny difference of distance from one clip position to the other seems it would be.

That makes engine Very sensitive/responsive to Needle Position changes.

If You change the Needle Position and Do NOT get a distinct and significant Change in Engine Performance,,,
That's a very good clue that the needle's Jet is
clogged.

While Riding it at that "spot" where it misbehaves,,
try Very Slightly backing off the throttle a Little.
If you feel engine pull a bit harder as throttle is closed----thats a lean Needle or Needle Jet/ or clogged needle jet

You can TRY a heavy dose of Fuel Injection Cleaner added to fuel,,
but the needle jet happens to be the Least affected part of the carb by Cleaners.
TUFF for fuel cleaners to clean the needle jet Right because of how the jet works & is made.

Which means You'll probably need to remove carb,disassemble,and clean it throughly.

Carb parts DO Wear.
Needles and their jet experience Physical Friction during operation,,,and are thus prone to wear which produces a change in their calibration.

They always wear "RICHER".
A High Mileage carb will often begin to run rich in 1/2~3/4 Throttle range.

Yours sounds to be obviously LEAN at that throttle position range.

That symptom of Fuel Shortage is what indicates
the likelihood of the Needle Jet being clogged.

Start/Idle/Low Speed running OK?
=Pilot Jet OK
=Airleaks Unlikely

High Speed/Full Throttle OK?
=Main Jet "close enough" to correct

Bogs,Power Loss @ 3/4 Throttle range?
=Lean Intermediate fuel delivery-->>Needle/Jet

Can't be WORN,,,that produces RICH mixture which results in Stuttering,blubbering similar to running on choke or lightly fouled plug.

Logic of how it all works leaves Clogged Needle Jet as prime suspect.

Only other possibility would be a VERY Worn ThrottleSlide/carb Body.
But That condition acts very similar to Air Leak at idle & low speeds.
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Thanks

 

LOL, I presumed a thorourh cleaning was performed.
Please let us know how you make out. [img]i/expressions/face-icon-small-smile.gif[/img]

 

LT80, the carb I have on the ETON is a 18mm Mikuni. Are you familiar with this carb. Like I stated I have taken this apart mulitple times and cleaned everything (except the needle jet). Any tips or advice how to get this out. I am planning on doing this tomorrow so any advice is appreciated.
Also I am wondering if I see clogged jets on that needle jet should I remove the shims under the jet needle and go back to the 85 main as a starting point. Thanks

 

I removed the jet needle with the hopes that it would be clogged and a thorough cleaning would get me squared away. The jet looked good but I cleaned it and put back together. There were no notches to line up the nozzle so I assume that it can go back in any position. I need my daughter to test drive again to see if the mid range and top end are better. I also ordered a 100, 105 and 110 main jet that are on there way. It still seems to me that going from an 85 to a 100 is a lot especially since my 05 viper still has the 85 main jet after oil injector removal and is running good. Still need to swap carbs to test if cleaning does not help.

 

I would do a compression test. Should be over 100psi. Sounds similar to my sons 2003 eton 90, before I redid the top end.

 

Do I need a special gauge atv specific gauge for that? I assume I just take out the spark plug and crank it over? Thanks

 

<div class="FTQUOTE"><begin quote>Originally posted by: GMoney69

Do I need a special gauge atv specific gauge for that? I assume I just take out the spark plug and crank it over? Thanks</end quote></div>

Hold the throttle wide open during the test.

 

Hello, Sorry for the long delay. I was trying to get my hand on a compression tester. Both the viper that are running good and the other one blew a 90. I was using a press in type tester so the numbers might be low but if there was a problem I would expect them to be different.

I got my new jets. Stock main jet was 85 then I went to a 90. Would it be uncommon for this quad to need to go up to a 100 main jet. With the 90 I shimmed the needle jet with 3 washer and it did not make a bit of difference.

As always advice appreciated.