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Enduro Intake/Carburetion - 2 stroke Jetting, Reeds, Air Filters, etc.


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Old 01-24-2007, 12:00 PM
gasIdaho gasIdaho is offline
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Default Pre-Mix ratio

Was wondering what the concensus is regarding pre-mix ratio using fully synthetic oil. I run 50:1 Maxima full-syn on my 05' EC300 and use 92/93 octane gas.

Reason I ask is b/c lately the "drool" off the end of my pipe has not been there. Am I running too lean? No changes have been made to the bike in some time. Only difference is I've been riding in 35-40F temps. Should I add a bit more pre-mix?


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Old 01-24-2007, 12:30 PM
jeffd jeffd is offline
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Some will disagree with me, but...

This dribble is usually affectionately referred to as "spooge". To me, having a little dribble down the tail pipe is a sign that the motor is getting good lubrication. And frankly, I am glad to see a little versus a little worried if I don't see any. It is a 2 stroke and much of the fuel leaves the tailpipe unburnt.

I prefer to run 36:1 synthetic (mobil-1 is my favorite) - my thoughts are that the 50:1 recommendation from the manufacturer is partly to keep smoke and emissions to a minimum. I prefer to have a little extra oil in the mix - better ring seal and more lubrication to the bottom end crank bearings, etc. Also, the oil film on the cylinder walls helps to transfer heat away from the piston.

It sounds like you are happy with your jetting now. What are your jetting specs. Does the bike respond well throughout the rpm range?

jeff
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Old 01-24-2007, 01:02 PM
gasIdaho gasIdaho is offline
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I'm running a 168/45, #7 slide, #3 needle clip on a -0 needle(LTR Kit). I bought this bike from a friend who had it set-up by MotoTech, our local GG dealer. I believe it's set-up for 5000ft elevation. I'm currently riding at 2-3k elevation. I've never messed with anything on the carb as the bike seems to run great at all RPM's. I'm interested in keeping her well lubed..I don't care about a little extra smoke or spooge. I'm wondering what affect it would have if I went to say 40:1..or 36:1?
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Old 01-24-2007, 01:11 PM
jeffd jeffd is offline
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I don't know about the maxima - but I like mobil-1 synthetic run at 36:1.

It runs very clean and I have never fouled a plug with it.

jeff

p.s. If you do want the bike to run more cleanly - consider having the RB-Designs head mod done. The squish band is typically set up very loose on the bike - it runs much better after it is dialed in and the compression ratio is dialed in. A friend pinged me about a minor jetting issue recently - and I suggested he do this first.
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Old 01-24-2007, 01:38 PM
gasIdaho gasIdaho is offline
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I'm doing my top-end pretty soon as the bike has approx 2000mi's on the original. After the break-in I'm going to do the RB head mod. I may just cut my pre-mix back to 40:1 and see how she goes.
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Old 01-25-2007, 09:55 PM
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GMP GMP is offline
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I was running 36:1 Amsoil dominator, clean to a hair rich LTR jetting, and RBD head mod. I have both an FMF silencer and silencer SA. The bike spooged a bit with the SA because it tends to trap the oil mist as trys to escape, where with the straight silencer it blows right through. The inside of the motor(lower end) still looked great after 4 seasons, and the seasonal top end comes out looking good as well. The head and PV were very clean, head actually still shiny with NO deposits on the squish area. You should not attempt to "jet" the bike with ratio changes. Its been proven on a dyno that richer oil/fuel ratios make the most power.
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Old 03-20-2007, 09:52 PM
mattmax mattmax is offline
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Default mix ratio/spooge

Quote:
Originally Posted by gasIdaho View Post
Was wondering what the concensus is regarding pre-mix ratio using fully synthetic oil. I run 50:1 Maxima full-syn on my 05' EC300 and use 92/93 octane gas.

Reason I ask is b/c lately the "drool" off the end of my pipe has not been there. Am I running too lean? No changes have been made to the bike in some time. Only difference is I've been riding in 35-40F temps. Should I add a bit more pre-mix?
explaining fuel mixtures, lean and rich, can get real confusing when you are talking about lean gas/oil, rich gas/oil or gas/ air mixes because the same terms have opposite meanings sometimes.

I take it that 35-40F temps are lower than what you usually ride? Lower temps run better with richer air/fuel mixes, that's why a bike likes the choke longer when it's cold out, and when hot, the choke loads up the plug quickly.

Also, the best way to eliminate "spooge" is to jet your bike correctly. A properly jetted bike will cease to smoke once warmed up, even if using a high oil/gas mix. The biggest mistake people make when trying to eliminate spooge is to go to a leaner oil/gas premix ratio. While burning less oil per amount of gas, the space left by the less oil is now filled with gas, so you wind up with a richer air/fuel mix with less oil. Now you have a bike that runs richer air/fuel wise and has trouble burning off the oil because it doesn't burn the fuel properly, such as the right temp to vaporize the oil better and it produces less power because air/fuel jetting is off, plus,it's more likely to foul a plug.

Higher temps like leaner air/fuel mixtures because the less dense air needs less fuel, similar to high altitude. If you have the proper air/fuel mix the amount of oil in the mix should make little difference because it will burn off - the trick is to jet it at that oil/fuel mix, because oil takes the place of gas in the mix. When it comes to eliminating spooge, most peopls instincts are opposite of the fix. They want to add less oil, which actually richens the air/fuel mix, making for a bike that can both gas and oil foul your plug.

Guys who have a real good handle on jetting carbs will pick a medium oil ratio for their medium ride temp, and jet the bike there, say at 60F, 40:1. When it's cold out, they can richen the air mix by running maybe 50:1, and when it's real hot, they can lean the air/fuel by running 30:1.

These are just rough examples. The trick is to jet your bike at your average temp and at a mix ratio and oil you are going to stick to. If it spooges, your mix is off, and that's fixed through jetting, not messing around with less oil. A lot of motorcycle brand oils are no better than weedeater specials. We all know Honda doesn't have a oil well in the Gulf, and Kawi doesn't have the money to develop their own polymers for a good synthetic. Yamaha race oil is supposed to be good, but this new Mobil 1 2t race is supposed to be real good and i trust a name that makes top notch oil.

Also, watch for jetting too lean, a main or clip can burn up a motor. The tuning guys always say you'l notice it first, but I think that's just Them. Look for a motor running extra hot suddenly, and check the plug. If you are dangerously lean, the plug wil show it without doing your typical plug test
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  #8  
Old 03-20-2007, 11:27 PM
onebrow onebrow is offline
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Maxima recommends oil ratio based on type of riding check this thread: www.maximausa.com/technical/oilmigration.html
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Old 03-21-2007, 11:17 AM
Triple W Triple W is offline
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I.ve always run Golden Spectro @ 50:1, Never a problem. If the bike was jetted for 5000ft and your ridin' at 3000ft you may want to richen up the jetting. Read the plug that is the key.
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