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


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Old 02-19-2007, 02:04 AM
Leon_gasgas Leon_gasgas is offline
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Default 100% synthetic oil not when below 0o C?

Hi!

My new '07 EC250 does not like full throtle in temperatures below freezing. The bike is crisp and nice until you try to give it full throtle quickly. It hesitates. If I close a bit the throtle, it revs out nicelly. Scared of the engine not getting enough petrol, I tried a 185 main jet after break in. Not good at all, rich everywhere... Went back to the 180 and emmediatelly was much better. I played as well with the air screw and things got even better. Currently at 2 turns out and tonight I am going to try 2,5 turns.

The manual says not to use 100% synthetic oil when it's cold. I used Mobil 1 and now Castrol TTS with no difference between the two. And of course here in Finland we use antifreezing liquid... Also, I get a lot of the black spooge out of the silencer.

Should I try a semi-synthetic oil following the manual, or keep trying setting the jetting right? I didn't have any similar problems with the '98 as long as I used the correct main jet. And always I used 100% syn oils.

Thank you for any replies!

Leon


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Old 02-19-2007, 05:32 PM
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That doesn't sound right. I've never read an '07 manual but have never heard of that before. My bikes have run fine from around 10 to 100 deg F, same 36:1 Amsoil Dominator premix, minor jetting changes. I never even needed to block one rad off. Kent A rides all winter in Sweden and has no problem either.

Does it bog/surge hesitate, or blubber hesitate?

What do you mean by "antifreezing liquid"?? If you mean a fuel additive like ethanol to absorb moisture and prevent fuel line freezing in automobiles, that could really lean your jetting out in addition to the cold. You shouldn't need that as long as you use known good fuel.

My guess is your lean on the needle, maybe boarderline lean when its warm so it feels worse when cold and possibly compounded from your fuel. The carb circuits have more overlap than you think.
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Old 02-19-2007, 06:43 PM
Dave Dave is offline
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Leon,
Does your '07 have an intake restrictor? One of those would really reduce top end power.
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Old 02-20-2007, 02:18 AM
Leon_gasgas Leon_gasgas is offline
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Thank you for the replies!

Yesterday with -10 C and the screw 2,5 turns out the bike worked better. I didn't want to press it but one or two times I tried a bit and the top power felt right. Still this black spooge comes out of the silencer but I think it was less.

I received the bike ready for competition. There are no restrictions. With the throtle open (let's say) 95% the bike was revving out nicelly. As I wrote, I tried a 185 main jet and it didn't like it at all. It was barely moving... With the 180 now I don't think I am on the lean side because the bike works very nice. Good torque and everything except this tiny hesitation on really full throtle.

My friend with a KTM250EXC '06 mentioned as well that with the one size bigger main jet in the winter, the air screw had to be 2,5 turns out in order for the bike to work good.

I called as well the main distributor of Finland asking if somebody else had this problem and said no. From my description he recomended to try even a 178 jet. I won't do it. I want to be on the safe side because the bike does not foul plugs and works great generally. Especially right now.

I have to think about this antifreezing liguid.. Thank you Glenn for mentioning it.

Leon
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Old 02-20-2007, 04:25 AM
Leon_gasgas Leon_gasgas is offline
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Glenn, thinking your comment about this liquid, I am going to remix new petrol (with the recommended amount of oil) with the petrol there is now in the tank. I think I have been using too big amount of this antifreezing liquid being afraid that the petrol can freeze too easily. I remember I never used that much of this liquid in the '98 EC250 and the bike never had such a problem. Good that our paths here are slow and technical. I never pressed the bike near the redline during these 22 hours I have driven it. Mainly low and mid to start of top end revs.

Thank you again for this comment!! You might just have saved the life of this amazing 07 engine!

Leon
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Old 02-20-2007, 05:44 AM
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Leon,

I don't have much experience with below freezing running but ....
You are running mostly tight tracks, when you go for full throttle is it just an instant & you back off or do you spend a while trying with it wide open?

Reason is when I was playing with my jetting a while back when it was too rich I had loads of black spooge and after a while in the woods it would hesitate on full throttle and take a few seconds to clear, then it would rev out.

Try it on a flat open bit - maybe cover the rad to make sure you don't cold sieze. Obviously it wont run right if the engine isn't getting hot enough - warm it up and see if it'll run WFO. If it clears after a few seconds then revs out you probably are too rich.

I once fully covered both sides of my rad (thinking I would remove one side later and forgot) when it was about 0 deg C. It ran for 1.5 hours before boiling and I think that was only because the air temp had risen to about 5 deg C.

Ian.
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Old 02-20-2007, 07:10 AM
Leon_gasgas Leon_gasgas is offline
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Ian,

the bike has the same symptoms (black spooge and hesitation at full throtle) as yours when you were trying to jet it right. It is confusing because last week opening half turn the air screw it improved things very much. And yesterday felt even better with an additional half turn out. Glenn is right about this liguid changing the mixture percentage of the fuel which might cause lean running. That's why today I try to reduce the antifreezing liquid amount and test.

On Saturday afternoon with the same jetting it was +3 about C and after a period of about 15 min with 2nd and 3rd gear tight tree driving I attacked a snow berm and gave full throttle in 2nd from the start of the berm. The bike coughed like crazy. Reduced the throtle and then I was able to accelerate pretty ok through the gears. I think this is a rich situation. Should I try the178 jet? The bike always starts first kick and works great if I keep the throttle at 80ยป90%.

Leon
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Old 02-20-2007, 08:13 AM
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You don't need that stuff. Its colder than that here now in NJ. We have ethanol in our pump gas as an oxygenate for emmissions reasons. To minimize effect on jetting, I mix race gas(no ethanol) 50/50 when its cold out like late fall early spring. Another bad thing is that ethanol absorbs water, and can cause some oils to separate from the fuel. I have seen this first hand. You have to live with whats in the fuel from the refinery but certainly don't add more.

Also don't pay too much attention to spooge. Its related to the oil flash point and fuel additives as well as mixture. My bike spooged plenty but ran like an animal.

Is it just temp related or snow related? Vent lines blocked with snow?
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Old 02-20-2007, 12:01 PM
Leon_gasgas Leon_gasgas is offline
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Yes, the vent lines can be blocked from snow and the problem is temp related. At least the finns say so... That's why we protect the carb from snow and ice by placing in front and around of it a piece of "tent bed". The Finn in the board can confirm . I know for sure that the petrol from the stations for the winter period is different than the one offered in the other periods. It has to do with the ethanol you mention... And the liquid we use I think it has some "poly.." (I don't remember the word) and not ethanol in order not to absorb water. I have to confirm this.

I had to quit a race last year with the '98 EC frozen, full of ice around the carb, fouling plugs every ten minutes.. I run out of plugs and patient ... I don't want this to happen again. That's why I want to be very careful with the new bike. At least the 1st race last week went ok.

First thing is to reduce the amount of this liquid in the mixture and test. I just bought some Valvoline Competition semi-synthetic oil which is recomended only for enduro and mx and only for premix. Soon I will test it... The seller told me that (and following what is written in the gg manual..you can find the 07 manual from gasgasmotos.es) it is not recommended to use 100% syn oil for the 2T snowmobiles. Only semi-synthetic like the Motul snow power... It has to do with corrossion...

The next race is next week in an area with more snow. The bike will be ready for sure..!

Thank you for your replies!

Leon
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Old 02-20-2007, 02:01 PM
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While you at it split your vent lines and run one from each side up high, the othe two and drain line low. That will eliminate any potential snow blockage problems.

Since this "antifreeze" is unknown, so are its burn charactaristics. Try it with no additive and see how it runs.

I'll have to look at the '07 manual. What is known is that oils with an Ester base, while providing the best lubrication, are not good for storage because the Ester absorbs water very fast. Maybe there concerened with a cold bike brought into warm garage or storage, forming a lot of condensation.

PM Kent A, he rides all winter in Sweden and knows GGs as well as anyone. Nice guy, I'm sure he'd be happy to help you.
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