automagp68 Posted June 30, 2015 Report Share Posted June 30, 2015 Ok so i must admit never run a bike this lean. Is 70:1 really the going ratio for these machines I tried my 50:1 i run in my KTM and i can just tell its to much. Its just oil every where and feels sluggish on throttle response. Does not smoke to bad on the 50:1 but i can just tell its to much Bike is properly jetted for my altitude My quick mix cup does not even go to 70:1 Is that what you guys are all running? Quote Link to comment Share on other sites More sharing options...
michael_t Posted June 30, 2015 Report Share Posted June 30, 2015 Some go to 100:1 but I stick with 80:1 Quote Link to comment Share on other sites More sharing options...
automagp68 Posted June 30, 2015 Author Report Share Posted June 30, 2015 so is it expected that my 50:1 feels like total crap? Quote Link to comment Share on other sites More sharing options...
fxstbi Posted June 30, 2015 Report Share Posted June 30, 2015 80-1 on my '15 Sherco 250. You need to get a big bore syringe to get an accurate cc measurement. 48cc's per gallon for 80-1. Quote Link to comment Share on other sites More sharing options...
automagp68 Posted June 30, 2015 Author Report Share Posted June 30, 2015 80-1 on my '15 Sherco 250. You need to get a big bore syringe to get an accurate cc measurement. 48cc's per gallon for 80-1. Nice thanks for the info how did you figure out the calculation out of curiosity? Quote Link to comment Share on other sites More sharing options...
10k Posted June 30, 2015 Report Share Posted June 30, 2015 Google is your friend: http://www.csgnetwork.com/oilfuelcalc.html Quote Link to comment Share on other sites More sharing options...
geodet Posted June 30, 2015 Report Share Posted June 30, 2015 I run 80:1 but buy my fuel 4 litres a time. The oil then works out at a convenient 50 cc. 4000 / 80 = 50. Not sure where you are located but be aware fxstbi calculations are for American gallons. Quote Link to comment Share on other sites More sharing options...
michael_t Posted June 30, 2015 Report Share Posted June 30, 2015 Yeah isn't metric great . I only mix up 4 litres (with 50cc) as well. Given people run from 50:1 to 100:1 I just use a kitchen measuring cup (don't trust the side of the bottle) instead of a syringe. I also use a bit of the gas to rinse out the measuring cup and pore it back into the mix. I should note that even though my X-Ride has the same motor as the Sherco ST290 I run it at 50:1 (5 liters with 100cc) as I ride it more as a trail bike than a Trials bike. Quote Link to comment Share on other sites More sharing options...
fxstbi Posted June 30, 2015 Report Share Posted June 30, 2015 Nice thanks for the info how did you figure out the calculation out of curiosity? As noted these figures are for US gallons. Take 128 (ounces in a gallon) and divide x the ratio you want (80) 128/80=1.6 Multiply 1.6 x 29.5729 (how many cc's in an ounce) and you get 47.316cc's There are lots of online calculators that make it easy but if all you have is a pencil you can do it this way. Quote Link to comment Share on other sites More sharing options...
automagp68 Posted June 30, 2015 Author Report Share Posted June 30, 2015 Cool thanks So seems like most of you are on the 70 or 80 to 1 program? The other issue i keep having is i oil leaking from my header pipe. I replaced the seal in there and it still does it. Its much much worse when i go into the mountains way up high where the bike is running very very rich so i know its a mixture issue. I rejetted and that helped the leaking a lot but still does it some. I think the root cause is my 50:1 mix Quote Link to comment Share on other sites More sharing options...
t-shock 250 Posted June 30, 2015 Report Share Posted June 30, 2015 Yes, you're putting too much oil in for it to be burnt, hence it passes straight into the exhaust, and because re-packing the sherco silencer isn't an easy job you're making a job for yourself. Quote Link to comment Share on other sites More sharing options...
automagp68 Posted June 30, 2015 Author Report Share Posted June 30, 2015 80-1 on my '15 Sherco 250. You need to get a big bore syringe to get an accurate cc measurement. 48cc's per gallon for 80-1. Got me a syringe today. Will give this a go and see if i can blow up my engine! Will get exactly 1 gallon and do exactly 48CC of oil Thanks for the help Quote Link to comment Share on other sites More sharing options...
fxstbi Posted June 30, 2015 Report Share Posted June 30, 2015 It won't blow up! (Disclaimer) as long as you are jetted correctly. Do make sure you are using a full synthetic 2T oil. I have two KTM two strokes and I had to get past the mental block of "that's not enough oil" for my trials bike. When you find out that everyone is running their modern trials bikes at these ratios and you put some time on your bike you'll get comfortable with it. Quote Link to comment Share on other sites More sharing options...
automagp68 Posted June 30, 2015 Author Report Share Posted June 30, 2015 It won't blow up! (Disclaimer) as long as you are jetted correctly. Do make sure you are using a full synthetic 2T oil. I have two KTM two strokes and I had to get past the mental block of "that's not enough oil" for my trials bike. When you find out that everyone is running their modern trials bikes at these ratios and you put some time on your bike you'll get comfortable with it. Thanks Just filled her up as directed and gave it ago Seems to run fine Im still trying to get a little bit more throttle response. Where are you guys typically setting the air screw on these bikes? I feel like my pilot just is insanely large My local sherco go told me to put a 52 pilot in because they like them super rich down bottom. Is that because we are hardly moving and the bikes is always really hot? If it were super hot and lean i could see that being an issue. Is that kinda the idea here? Right now I'm running 52 pilot, and 118 main. I ride 7-8k elevation regularly I just feel like its very slow revving compared to my ktm is all Like it sorta drags its ass to the top of the rpm range. Just installed a fresh plug also Quote Link to comment Share on other sites More sharing options...
fxstbi Posted July 1, 2015 Report Share Posted July 1, 2015 My 250 is stock with the factory jets, 122 main and 33 pilot, I tweaked the air screw maybe 1/4 and it runs great. I'm at about 1,000 feet MSL. My '15 spools up quick and my wife's '13 spools up a little slower because it has a flywheel weight. You might check and see if your bike has one, look for an extra spacer on the ignition side cover. Quote Link to comment Share on other sites More sharing options...
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