charlie46 Posted July 23, 2013 Report Share Posted July 23, 2013 Evening folks, I bought myself an 08 rev 3 250 about 3 weeks ago. Thoroughly pleased with it and starting the basics of trials. However, when I was out practising this evening, it felt like the bike was very keen to stall? As in at low speed in first or with the clutch pulled in, I had to continually pick the revs up in order to prevent a stall. What might this be the result of, my initial thoughts were spark plug (don't know when this was last changed) or a jetting issue (would seem strange that it was okay with the previous owner)? Thanks in advance for the help guys. Cheers, Charlie Quote Link to comment Share on other sites More sharing options...
nelly1 Posted July 23, 2013 Report Share Posted July 23, 2013 how clean is the air filter ? possibly a blocked jet i would change the plug and gear oil for peace of mind Quote Link to comment Share on other sites More sharing options...
charlie46 Posted July 23, 2013 Author Report Share Posted July 23, 2013 The air filter is filthy! New one on order, would it make a considerable difference? I will get a new plug as well, can I ask why you suggest gear oil? I changed it last weekend? Thanks for the help Quote Link to comment Share on other sites More sharing options...
nelly1 Posted July 23, 2013 Report Share Posted July 23, 2013 only for peace of mind didnt know you had changed it you could wash and re oil the one you have 1 Quote Link to comment Share on other sites More sharing options...
lineaway Posted July 24, 2013 Report Share Posted July 24, 2013 Actually changing brand of oil could cause a `change`. Also being new to trials, are you sure it`s not yourself hitting the rear brake? Quote Link to comment Share on other sites More sharing options...
charlie46 Posted July 24, 2013 Author Report Share Posted July 24, 2013 only for peace of mind didnt know you had changed it you could wash and re oil the one you have Thanks for the advice. Hopefully the filter and plug will make a difference. Is it worth adjusting the idle on the carb? Quote Link to comment Share on other sites More sharing options...
charlie46 Posted July 24, 2013 Author Report Share Posted July 24, 2013 Actually changing brand of oil could cause a `change`. Also being new to trials, are you sure it`s not yourself hitting the rear brake? Interesting, I didn't realise this! Is it then worth adjusting the carb to compensate? Definitely not riding the rear brake, seem to spend my life on my toes! Thanks for the advice Quote Link to comment Share on other sites More sharing options...
0007 Posted July 25, 2013 Report Share Posted July 25, 2013 Transmission oil won't cause your bike to not idle And you should absolutely acquaint yourself with the idle and air screw, have an experienced guy walk you through air screw setting and you will get it figured Quote Link to comment Share on other sites More sharing options...
liviob Posted July 26, 2013 Report Share Posted July 26, 2013 (edited) Congrats on the new bike Charlie! Is this your first motor bike? After you warm the engine up will it idle with the transmission in neutral? or will it not idle when you have the transmission in gear with the clutch lever pulled in to the grip? Was the clutch dragging pulling engine RPM down? As others have mentioned you can clean your air filter with solvent and reoil it before reinstallation. If after installing a clean and oiled air filter your engine still will not idle properly try turning the idle screw "its the screw on the side of the carb with the spring on it" in 1/16th turn. The idle should raise some if it doesn't try adjusting the air screw "its the slotted brass screw closest to the intake bell of the carb" It should be set anywhere from 1 turn out from full closed to 2 1/2 turns out from full closed. See where its set then reset it to 1 1/2 turns out from full closed position. Edited July 26, 2013 by liviob Quote Link to comment Share on other sites More sharing options...
dan williams Posted July 28, 2013 Report Share Posted July 28, 2013 The '08 uses the Keihin carb and it is finicky around water. If you've got any water in the fuel or you've been out in wet conditions it is possible to get a water bubble in the pilot circuit that will sit in the air passage that comes out just behind the throttle slide on the bottom side of the carb body. This water bubble won't evaporate as the passage is small and surface tension holds the bubble together. I chased one of these for quite some time before I figured it out. The best thing to do is pull the carb out, start by sliding the back air boot as far as possible back onto the airbox, and disassemble and clean all the carb circuits. The main jet tower requires a security torx bit. (star bit with a hole drilled into the center) if you really want to take it all apart. Important to blow out all the air passages with compressed air. Quote Link to comment Share on other sites More sharing options...
charlie46 Posted August 6, 2013 Author Report Share Posted August 6, 2013 Congrats on the new bike Charlie! Is this your first motor bike? After you warm the engine up will it idle with the transmission in neutral? or will it not idle when you have the transmission in gear with the clutch lever pulled in to the grip? Was the clutch dragging pulling engine RPM down? As others have mentioned you can clean your air filter with solvent and reoil it before reinstallation. If after installing a clean and oiled air filter your engine still will not idle properly try turning the idle screw "its the screw on the side of the carb with the spring on it" in 1/16th turn. The idle should raise some if it doesn't try adjusting the air screw "its the slotted brass screw closest to the intake bell of the carb" It should be set anywhere from 1 turn out from full closed to 2 1/2 turns out from full closed. See where its set then reset it to 1 1/2 turns out from full closed position. Hi Liviob, Thanks for the reply, some really good advice in there. Fairly new to this bike but I used to have gas has 125 when I was younger, doesn't mean to say I'm any use though! Idling in neutral can be a bit hit and miss, idling in gear with the clutch in seems to be more common in terms of the revs dropping and stalling. I have cleaned the air filter out and the problem is still there somewhat. I can fix it with the idle screw but it then seems to rev too high. Also an interesting point is that I noticed it revved too high when leant over to one side but settled upon being righted...not sure if this is a throttle cable issue or maybe the carb? With regards to the air screw is full closed fully turned inwards into the bike? Thanks again, Charlie. Quote Link to comment Share on other sites More sharing options...
charlie46 Posted August 6, 2013 Author Report Share Posted August 6, 2013 The '08 uses the Keihin carb and it is finicky around water. If you've got any water in the fuel or you've been out in wet conditions it is possible to get a water bubble in the pilot circuit that will sit in the air passage that comes out just behind the throttle slide on the bottom side of the carb body. This water bubble won't evaporate as the passage is small and surface tension holds the bubble together. I chased one of these for quite some time before I figured it out. The best thing to do is pull the carb out, start by sliding the back air boot as far as possible back onto the airbox, and disassemble and clean all the carb circuits. The main jet tower requires a security torx bit. (star bit with a hole drilled into the center) if you really want to take it all apart. Important to blow out all the air passages with compressed air. Hi Dan, Thanks for the reply, the carb sounds interesting, as I mentioned the idle changes based upon the lean angle of the bike sometimes. It also appears to be an intermittent problem, hence this bubble idea may be likely. I have washed the bike a couple of times although not using a pressure washer and trying to avoid the carb. Does this sound feasible for water ingress? Cheers, Charlie. Quote Link to comment Share on other sites More sharing options...
dan williams Posted August 9, 2013 Report Share Posted August 9, 2013 I'm afraid the best course of action is the usual, take it apart and do the fixes/adjustments/cleaning and then put it back together and see how it runs knowing at least the carb is sorted. All else is speculation. Idle changing from lean angle is a little weird but I'd suspect float level. The water bubble in the exit hole of the pilot circuit is not really variable. When it happens the bike runs awful in the lower throttle range all the time until it's cleared. Quote Link to comment Share on other sites More sharing options...
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