scotty97 Posted April 20, 2009 Report Share Posted April 20, 2009 When i shut off the throttle on my 2004 beta rev 3 the revs stay up and then gradullay wind down to tick over, on other bikes the revs drop as soon as you close the throttle. any ideas what could be causing this. air filter, plug etc all look ok Quote Link to comment Share on other sites More sharing options...
jfc Posted April 20, 2009 Report Share Posted April 20, 2009 Have you checked the throttle cable is not sticking / binding or that the slide is dirty and causing the slide to close slowly. (when the engine is off can you hear the throttle snap shut when you release the twist grip) Quote Link to comment Share on other sites More sharing options...
ming Posted April 20, 2009 Report Share Posted April 20, 2009 When you say "on other bikes" do you mean trials bikes or road/enduro bikes? I was amazed at how slow the revs drop on my 2000 Rev3 compared to my 450cc enduro bike - apparently that's normal and I guess down to the heavy flywheel action? If it's different to other trials bikes then you need to investigate further. Quote Link to comment Share on other sites More sharing options...
zarkoff Posted April 20, 2009 Report Share Posted April 20, 2009 When i shut off the throttle on my 2004 beta rev 3 the revs stay up and then gradullay wind down to tick over, on other bikes the revs drop as soon as you close the throttle. any ideas what could be causing this. air filter, plug etc all look ok hi there i was once told that if you had a small split in the rubber tube joining the carb to the engine this is what would happen, basicaly any air getting in by any other means than through the filter, i would just check it out i hope this helps Quote Link to comment Share on other sites More sharing options...
scotty97 Posted April 20, 2009 Author Report Share Posted April 20, 2009 cheers 4 replies, checkd throttle cable, and throttle seems to snap shut ok when bike isnt running, no sticking. Bike defo revs on 4 a lot longer than the trials bike i saw in trial on sunday. (could prob count to ten in the time it takes 4 revs to drop). Any more things i could try? Quote Link to comment Share on other sites More sharing options...
scotty97 Posted April 20, 2009 Author Report Share Posted April 20, 2009 cheers 4 replies, checkd throttle cable, and throttle seems to snap shut ok when bike isnt running, no sticking. Bike defo revs on 4 a lot longer than the trials bike i saw in trial on sunday. (could prob count to ten in the time it takes 4 revs to drop). Any more things i could try? Quote Link to comment Share on other sites More sharing options...
scotty97 Posted April 20, 2009 Author Report Share Posted April 20, 2009 carb rubbers seemed ok. Il have a good look tomoro and double check 4 any splits Quote Link to comment Share on other sites More sharing options...
zarkoff Posted April 20, 2009 Report Share Posted April 20, 2009 carb rubbers seemed ok. Il have a good look tomorow and double check 4 any splits worn crank seals are another way air could be getting in but a bit harder to check! it should shut off straight away though so there must be some thing wrong somewhere Quote Link to comment Share on other sites More sharing options...
billyt Posted April 21, 2009 Report Share Posted April 21, 2009 Hi Guys Pilot jet to lean.................... Simple. Cheers BillyT Quote Link to comment Share on other sites More sharing options...
scotty97 Posted April 21, 2009 Author Report Share Posted April 21, 2009 found a little slice in the rubber between carb and engine earlier, cant really tel if it goes all the way through the rubber and if its sucking air through it. Going to change that and hopefully that will cure the problem, if not il try adjusting the mixture. Quote Link to comment Share on other sites More sharing options...
billyt Posted April 21, 2009 Report Share Posted April 21, 2009 Scotty If there is an air leak in the rubber boot the bike would be running lean/crazy at all RPM's not just coming down from idle. When you snap the throttle shut the pilot jet is the only jet supplying fuel at that point. If the bike was on a high rev before you shut it down the cylinder is looking for lots of fuel and air as it winds down and sucking air like crazy. It is not the mixture screw but rather the pilot jet it self. The idle air screw maybe out to far also. Been there down that........ BillyT Quote Link to comment Share on other sites More sharing options...
scotty97 Posted April 22, 2009 Author Report Share Posted April 22, 2009 Cheers. Bike was revving high at tick over when i purchased it (and seemed to be revving high through range), adjusted tick over until revs sounded ok but then when you rev the bike and then shut the throttle, the revs take ages to drop. Im going to change rubber anyway due to the damage on it. Then i'l look at the pilot jet, BILLY, would i need to increase/decrease the size of the pilot jet, or can it be adjusted????? If it carries om like this i'l be an expert on carburetters!!! ha ha ha Quote Link to comment Share on other sites More sharing options...
billyt Posted April 22, 2009 Report Share Posted April 22, 2009 (edited) Scotty Adjust the idle screw down (in) low to afford/allow slow idle speed AFTER CHAINGING TO A LARGER PILOT JET. The pilot jet should be a standard as a #30 I change mine to a number #35. Check the number stamped onto the side of the pilot jet and tell us what it is. Also disconnect the throttel cable from the throttle tube and see what this does? Cheers BillyT Edited April 22, 2009 by BillyT Quote Link to comment Share on other sites More sharing options...
totalshell Posted April 22, 2009 Report Share Posted April 22, 2009 turn the 'idle screw in' to lowere the revs? surely that will raise the throttle and raise the revs? Quote Link to comment Share on other sites More sharing options...
scotty97 Posted April 23, 2009 Author Report Share Posted April 23, 2009 changed the rubber boot, adjusted the tick over, bike seems to rev fine now, and when u shut the throttle the revs drop nicely, but if u leave it idle 4 a couple of seconds and then open the throttle quickly it seems flat (coughs at the low revs) but then once revs r up a little, it revs fine. Any ideas? Quote Link to comment Share on other sites More sharing options...
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