long ride and now what?

[Street Ryderz]

So i went on a longish ride 100 miles total took me two and a half hours,have ridden longer and farther before no problems!all the way there 50 miles at 45-50mph nonstop no problems checked temp with hand held temperature sensor and between the head and cylinder was 285 f it was 360 f above the exhaust flange normal for my set up.Then i fueled up and headed back home ten miles or so in and it seemed like i was really rich now. I stopped briefly just to double check how much oil i put in and i had put 1.5 liters fuel and 25ml oil looked good but now what?the temp outside when i left was 13 c and it dropped to 6 c on the way back and i noticed that the intake had alot of condensation on it (big drops) will that be the same inside the intake or was it my mix or even the fuel i filled on the rez with that is supposed to be 89 octane..? oh and yes i looked at plug it is a little carboned.

 

[Steve Best]

The condensation is normal in some high humidity weather conditions.
Latent heat of evaporation chills the intake below the dew point.
Jetting changes drastically with temperature. It gets leaner with cold.
Perfect jetting at 20c will burn a piston at 6c.
I would have expected your plug to be ashen white.

Your oil mix seems pretty lean at 60:1.
I get better results with double the oil, 50ml for 1.5L

Steve

 

[Street Ryderz]

Thats what i thought it should have made the air/ fuel mix leaner from the cold so maybe my lean oil mix made the air/fuel richer and saved me? it was last jetted at 11-12 celsius

 

[Steve Best]

Usually going from say 32:1 to say 16:1 has a big effect on jetting, but as you go above 40:1 there is very little jetting effect to oil mix. Jetted well at 12c will usually be ok at 5c. Depending on how close you jet you have about a 10c window. Racers a lot less. Do you sled?

My son and I headed out one bright and sunny crisp morning on the sleds, Safari 377 and Elan300. Sleds worked great, got 10 miles from home and the Elan died. I towed it 2 miles and my 377 died. 4 pistons cooked from -20c temp.

Expensive lesson about temp effects on jetting.

Steve

 

[skyash]

I run 30ml to 1l ...and 15ml for half a litre anything under that just lost power at hi speed /temperature .

 

[Street Ryderz]

I have been using Lucas semi synthetic 2 stroke oil and it says for 32/1 mix is 4 ounces per gallon.so i have been putting 25-30 ml when fueling on the road for 1-1.5 liters.

 

[Street Ryderz]

unfortunately no i havent been on a sled in sometime now but thanks for the help!i like to bounce my thoughts off others who know to make sure my train is on the right track.

 

[Steve Best]

No.
32 parts fuel to 1 part oil is 1500ml of fuel / 32 = 46.875 ml of oil. 45-50 ml will be fine.
1000 ml fuel / 25 ml oil = 40:1
1500 ml fuel / 30 ml oil = 50:1

1000ml (1 L) fuel / 32:1 oil = 31 ml oil
1500ml (1.5L) fuel / 32:1 oil = 47 ml oil

I am embarrassed to say that my current sled is 4 stroke.

Steve

 

[Street Ryderz]

oh wtf so they just guessed at it by saying 4 ounces per gallon a gallon to me is 4.5 l, so i thought its one ounce for each 1 and 1/8 l and the converter i used said an ounce is 29.5 ml hence why i thought 25-30 ml was good.

 

[Street Ryderz]

It was beautiful here in southern On. yesterday 18.5 c so I drained what was left in my tank and float bowl, re jetted for temp with the size i run most of the season two sizes down from the other day when it was colder so now an 82.Refueled with a premix I had in my shop same mix i ran before refueling on the rez and no resolve it ran almost exactly the same as my return trip the other day!I then took the head off to investigate,like the plug the other day top of piston was carboned,head had a slight carboned oil residue that just wiped away the chamber in head is polished.I was actually expecting to find worn chrome or even just excessive wear!this cylinder has way over 1000 miles on it, its over ten years old now!But no the jug has normal wear some very fine thin lines from ring seating,the same as you would see after break in from new.I miked the cyl it still reads 47 ish sorry but i still use an old school veneer caliper,the compression fells the same i didnt check that yet because there is no real evidence of blow by on piston or the cyl either, so now im wondering if its just my plug going it starts and runs fine on the pilot jet and needle it just doesnt want to run clean in the top end on the same jet i had used for a month with no issue.