steve_earle Posted February 18, 2013 Report Share Posted February 18, 2013 Different premix will change the fuel to air ratio slightly but not cause a problem, I was running 80:1 with fully synthetic, I brought Some Ipone semi synthetic by mistake a couple of weeks ago, thought it was full synth! My bike runs exactly the same no change even at 50:1 on the semi to be on the safe side. I will go back to full when I run out next. From past experience running too much oil espacialy full synth at 50:1 will make the bike boggy and appear to run richer even though it will be leaner on paper.. Be interesting on others views on this Quote Link to comment Share on other sites More sharing options...
neo Posted February 18, 2013 Report Share Posted February 18, 2013 So I'm now the proud owner of a flywheel puller and two crank seals.... I hope these seals work for you Paul because they did nothing for me..... Might take a few ride to be sure but please updated us after that. >80:1 fully Syth is the way to go. All the best. Neo Quote Link to comment Share on other sites More sharing options...
copemech Posted February 19, 2013 Report Share Posted February 19, 2013 Different premix will change the fuel to air ratio slightly but not cause a problem, I was running 80:1 with fully synthetic, I brought Some Ipone semi synthetic by mistake a couple of weeks ago, thought it was full synth! My bike runs exactly the same no change even at 50:1 on the semi to be on the safe side. I will go back to full when I run out next. From past experience running too much oil espacialy full synth at 50:1 will make the bike boggy and appear to run richer even though it will be leaner on paper.. Be interesting on others views on this Not to worry, it will be fine on that at 80:1 as well. The stuff lubes fine, I would not porr in that much under normal trials use. Quote Link to comment Share on other sites More sharing options...
steve_earle Posted February 21, 2013 Report Share Posted February 21, 2013 Not to worry, it will be fine on that at 80:1 as well. The stuff lubes fine, I would not porr in that much under normal trials use. Thinking about it, I should be fine running less oil even with the semi, Most of our Trials don't have big long climbs or long runs between sections and I don't rev it to the moon, Just quick short zaps. I have always run full synth at 70 or 80 ish since getting back to trials and just remember the old days of old oils and 50:1. Thanks cope for the vote of confidence I will run a different mix now I know it's o.k. Quote Link to comment Share on other sites More sharing options...
snap1 Posted February 26, 2013 Report Share Posted February 26, 2013 I have raised the needle, checked jets with Chris and also done the flywheel seal so far. Not had much of a chance to try it it but was out at a new venue going steady and I have not experienced the overrun yet. Time will tell... Chris told me to try a full pressure check, block exhaust port with a piece of plastic and make a bung for the inlet manifold which will check more than the crank seals, which makes sense. BTW the flywheel crank seal was not visually bad at all... Quote Link to comment Share on other sites More sharing options...
neo Posted February 26, 2013 Report Share Posted February 26, 2013 Chris told me to try a full pressure check... That's the same thing as the "leak down test" I mentioned previously. I drilled through an old spark plug and glued in a tyre value stem..... easy to pump up that way. See if it holds pressure. And you can also take the crank case breather tube and put it into a glass of water to check for bubbles. All the best. Neo Quote Link to comment Share on other sites More sharing options...
snap1 Posted February 26, 2013 Report Share Posted February 26, 2013 Thanks neo, I was getting mixed up with a liquid leak down test when you meantioned before to test rings etc :-/ sorry. Thanks for the tip with the spark plug and breather! Quote Link to comment Share on other sites More sharing options...
neo Posted February 26, 2013 Report Share Posted February 26, 2013 No, no worries ;-) I did a full write up on "how I did it" on this forum somewhere and there were some good tips for the other guys too. Best of luck. Neo Quote Link to comment Share on other sites More sharing options...
snap1 Posted March 9, 2013 Report Share Posted March 9, 2013 Hi, Thought I would report back as things look positive. So first time out on the bike on a proper run, and first club trial! Seem to have lost the over running high rev issue, and idle hunting is very manageable now. I changed the flywheel side crank seal and lifted the carb needle, I presume the seal helped more than lifting the needle. Thanks again for all your help, really appreciated. If the issue arrises again I have plans of how to tackle thanks to your suggestions. Cheers Paul Quote Link to comment Share on other sites More sharing options...
copemech Posted March 10, 2013 Report Share Posted March 10, 2013 Hi, Thought I would report back as things look positive. So first time out on the bike on a proper run, and first club trial! Seem to have lost the over running high rev issue, and idle hunting is very manageable now. I changed the flywheel side crank seal and lifted the carb needle, I presume the seal helped more than lifting the needle. Thanks again for all your help, really appreciated. If the issue arrises again I have plans of how to tackle thanks to your suggestions. Cheers Paul All good then, did you get the Viton seals? Once again, this goes to reinforce my theory that the stock seals will only last 2-3 years with the alcohol induced fuels we get. I would plan upon doing the other side soon! Before the bike starts sucking or blowing tranny fluid! Quote Link to comment Share on other sites More sharing options...
dixon Posted February 20, 2014 Author Report Share Posted February 20, 2014 i seemed to solve the problem for a short while, by changing the needle size, crank/fly seals and a good carb clean. But it now seems im back at square one again,Revs wont drop straight away after throttle release and revs build when iddling sometimes, seems to be worse when warm. everyone who hears it says " sounds like shes running lean". i use 70ml of ipone strawberry oil to 5l of standard unleaded. my carbs clean, seals are fine, cant find an air leak, but my fan has stopped spinning on its own accord, with a gentle tap it spins fine though! (which is annoying) is fan knacked? Ive read most threads on this site as i try understand & do work myself but it seems this is a real issue around this year of sherco (2011) Quote Link to comment Share on other sites More sharing options...
copemech Posted February 21, 2014 Report Share Posted February 21, 2014 i seemed to solve the problem for a short while, by changing the needle size, crank/fly seals and a good carb clean. But it now seems im back at square one again,Revs wont drop straight away after throttle release and revs build when iddling sometimes, seems to be worse when warm. everyone who hears it says " sounds like shes running lean". i use 70ml of ipone strawberry oil to 5l of standard unleaded. my carbs clean, seals are fine, cant find an air leak, but my fan has stopped spinning on its own accord, with a gentle tap it spins fine though! (which is annoying) is fan knacked? Ive read most threads on this site as i try understand & do work myself but it seems this is a real issue around this year of sherco (2011) No Idea which carb you have but principal is the same regardless of bike, carb or year. ANY dirt particles or water droplets will cause this. You may never even see the culprit in a routine cleaning, yet removing the pilot jet in particular is recco so you may find a small strand of copper wire to pass through to insure there is no blockage from an opaque bit of sand. Blow out passages to insure no issues there. Absorbed moisture will settle out of the alcohol induced fuels. Condensation from your supply can may effect things. It can all come into play, so CLEAN is the word. Carbs must "breath" as well, through the bowl vents, which are also a potential entry point for water and dirt. May occur when washing or riding the bike, all things to keep in mind. All said, start over clean! Insure everything! Quote Link to comment Share on other sites More sharing options...
bwmwaima Posted February 21, 2014 Report Share Posted February 21, 2014 snap1, perform the pressure test that Chris (splat shop ) has suggested to make sure whole system is air tight. Air leak likely to be at rubber inlet manifold, been there and done that on two bikes now,first one a 2010 250. second one a 2013 cabbestany. Quote Link to comment Share on other sites More sharing options...
scottwitting Posted April 20, 2014 Report Share Posted April 20, 2014 Regarding the commnet "my fan has stopped spinning on its own accord, with a gentle tap it spins fine though! (which is annoying) is fan knacked?". I recently had to replace the thermostat on my 2011 290. With hindsight I had similar symptoms, having to tap the fan to get it going and it needing the bike to be hotter and hotter to cut in. It seems these fail gradually, not cleanly cutting in but starting to act as a resistor. Indeed when I removed my old one and tested it in the kitchen with a battery and a pan of water on the hob the resistance crept down as the water reached boiling. Connecting the fan in saw it blip slightly every now and again. When the new thermostat arrived a similar test saw it cut the fan in cleanly at much lower temps, just as it should! If you are experiencing this I would suggest testing/replacing the thermostat. Quote Link to comment Share on other sites More sharing options...
copemech Posted April 21, 2014 Report Share Posted April 21, 2014 Regarding the commnet "my fan has stopped spinning on its own accord, with a gentle tap it spins fine though! (which is annoying) is fan knacked?". I recently had to replace the thermostat on my 2011 290. With hindsight I had similar symptoms, having to tap the fan to get it going and it needing the bike to be hotter and hotter to cut in. It seems these fail gradually, not cleanly cutting in but starting to act as a resistor. Indeed when I removed my old one and tested it in the kitchen with a battery and a pan of water on the hob the resistance crept down as the water reached boiling. Connecting the fan in saw it blip slightly every now and again. When the new thermostat arrived a similar test saw it cut the fan in cleanly at much lower temps, just as it should! If you are experiencing this I would suggest testing/replacing the thermostat. That is good info, however one may simply jumper the thermo switch wires to see if it runs, then if not, test it with an external 12V source. You can boil all them pots if you like, but not me! Quote Link to comment Share on other sites More sharing options...
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