gary5173 Posted July 16, 2009 Report Share Posted July 16, 2009 Hi everyone. I own a 2005 Gas Gas TXT280Pro thats making a metallic clinking sound at mid revs upwards in every gear. Is this pinking. I've heard that using a higher octane fuel can help but can anyone advice what the carb settings should be. I.E fuel / air screw etc. I tried to download the user manual but apparently its not available for the 2005 model for whatever reason. I bought the bike second hand so would like to know what the base settings for the carb are in so I know if they've been altered. Advice much appriciated Quote Link to comment Share on other sites More sharing options...
motomerlin Posted July 17, 2009 Report Share Posted July 17, 2009 First off, check jet sizes in carb. You might be able to tune this out with the pilot screw. Possibly a de-coke is needed. Quote Link to comment Share on other sites More sharing options...
lowbrow Posted July 17, 2009 Report Share Posted July 17, 2009 If its something that's started recently and you haven't changed anything check for leaks on the intake side; particularly the face between the crankcase and the reed block/intake stub. The rubber intake stubs can also split, but always at the back, next to the exhaust, where you can't see! I always use super unleaded fuel too. Quote Link to comment Share on other sites More sharing options...
dschigoda Posted July 28, 2009 Report Share Posted July 28, 2009 Some guys mix in ~ 1/3 race gas (~110 octane u.s.) with their premium unleaded, in their trials bikes. Quote Link to comment Share on other sites More sharing options...
dschigoda Posted July 28, 2009 Report Share Posted July 28, 2009 Also, if the Premium contains 10% ethanol, I get pinking. But most of the pinking goes away when I use the 100% gasoline premium. When I've added 1/3 race gas, the motor seems to loose some of its power, and some of its "snap". I ride a 2002 GG 280 Edition. Quote Link to comment Share on other sites More sharing options...
jse Posted July 28, 2009 Report Share Posted July 28, 2009 Also, if the Premium contains 10% ethanol, I get pinking. But most of the pinking goes away when I use the 100% gasoline premium.When I've added 1/3 race gas, the motor seems to loose some of its power, and some of its "snap". I ride a 2002 GG 280 Edition. The race fuel will give you less "snap" due to it's slower burning properties (kinda like retarding the static timing a little, it changes the "Indicated Mean Effective Pressure" ie: there is a little less pressure buildup between when the plug fires and the piston reaches TDC). I use it in my 02' 280 Pro to smooth out the lower RPM power delivery (I'm a slow, old geezer) and it can be used by riders to adjust the power output in wet, sloppy conditions when traction is marginal (softer power delivery off-idle) and the radiator may get plugged with mud (the higher octane is a little insurance to resist detonation due to higher engine temps). Jetting on the 05' Pro (sea level) should be in the neighborhood of: MAIN: 116/118 PILOT: 36/38 NEEDLE: D36 (3rd, or 2nd CLIP POSITION DOWN FROM TOP) FUEL SCREW: 3.5 TURNS OUT TO START (adjust for ambient conditions) I run my 280 with a 118/38/2nd-clip combo with good results and never a "pink"..... Jon Quote Link to comment Share on other sites More sharing options...
stork955 Posted July 28, 2009 Report Share Posted July 28, 2009 Gday, Give it a good decoke (head off) and while you are at it, check your Carb as Jon said above, and clean the pipe from front to back. It should run like a beauty afterwards. It is a 2-stroke, burning all its oil after all. Cheers, Stork. Quote Link to comment Share on other sites More sharing options...
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