alphadecay Posted May 21, 2006 Report Share Posted May 21, 2006 FYI: I'm new to 2-stroke bikes, so I'm just learning the in's and out's of the motors and such. So I do have quite a few questions. Just over a month ago I bought a barely used 2004 TXT Pro 300 (not even a single scuff on the bodywork). Anyway, yesterday I was in 6th gear going up a dirt road (gently sloped upward) and after about 1 mile of this the bike died. It basically sputtered and quit. Exhaust smelled a bit funky. Kicked it a few times, nothing. Waited 5 minutes and it fired right up. I've never had a problem with the bike under normal trials-like conditions (the fan does come on fairly quickly when puttering around in 1st doing obstacles), and this was the first time I took the bike out and bombed up a road at such speed for the distance that I did. So my questions after this experience are: Is what I experienced just 'normal' overheating? My concern is if this can happen at 75F in temperate Washington, will I be overheating alot (meaning during slow trials riding) when I take this thing out to eastern Montana at 90F? Should I be concerned or do anything to the bike? In the future if this was to occur again, how should I deal with it? (I was worried I'd seize the engine or something if I overheated it and let it sit) How should I approach long, fast stretches like this if flying through it in 6th can cause problems? Using 80:1, 100LL Aviation Gas Yamalube 2-stroke synthetic for gas treatment 350cc of Dextron III ATF for oil Checked radiator fluid, its a nice green, filled to top of radiator Thank you for your time. --Tim Quote Link to comment Share on other sites More sharing options...
blocky Posted May 21, 2006 Report Share Posted May 21, 2006 (edited) Oil should be 550 cc Edited May 21, 2006 by Blocky Quote Link to comment Share on other sites More sharing options...
lewis_gasgas Posted May 21, 2006 Report Share Posted May 21, 2006 Maybe change down a gear ? 5 and 6 are more road gears on the pros ... so theres nothing there for them if you slow down 5 would be orite if you were going reasonably fast. But within reason you can actually set off in 3rd maybe even 4th (although that might not do the bike any good). Quote Link to comment Share on other sites More sharing options...
alphadecay Posted May 21, 2006 Author Report Share Posted May 21, 2006 Oil should be 550 cc <{POST_SNAPBACK}> Ok. I can understand if that was the problem. I was going off of the www.gasgas.com tech site recommendation (350cc) which brought it to 75% of window height. Further searching the forums here does say that 400-450 is good as anything more will get tossed out of the vent tube (manual reccomends 550cc). I'll change the oil today and put in more this time around. --Tim Quote Link to comment Share on other sites More sharing options...
perce Posted May 21, 2006 Report Share Posted May 21, 2006 Doubt your bike stopped through overheating. Check that the breather pipe on the petrol tank allows air to flow IN to the tank. Quote Link to comment Share on other sites More sharing options...
magicmat Posted May 21, 2006 Report Share Posted May 21, 2006 i've heard of people modifying the mud vent on the radiator to make cooling more efficent but havnt heard any specifics... anyone ?? when i give my bike a good blast down the road, the front pipe is the hottest i ever get it ! so... it wouldnt surprise me if the bike did overheat?? after all blasting isnt exactly what there made for ?? Quote Link to comment Share on other sites More sharing options...
lewis_gasgas Posted May 21, 2006 Report Share Posted May 21, 2006 I do plenty of "speeding" down the road in 5th and 6th gear mines never stalled or over heated . Quote Link to comment Share on other sites More sharing options...
jordi Posted May 21, 2006 Report Share Posted May 21, 2006 check the petrol tap is not blocked inside, this happened to an 03 of mine. excatly the same syptoms you describe. Had to take the tap out of the tank and unblock the hole. Fine afterwards. Quote Link to comment Share on other sites More sharing options...
lineaway Posted May 21, 2006 Report Share Posted May 21, 2006 The other things you failed to mention is elevation and jetting. Unfortunately it sounds like you seized the piston. Quick check with the header pipe off! Our modern bikes do not make good trail bikes. My bet is your riding at elevation which is very hard on the motor. Between 02-03 gasgas slightly enlarged the oil capacity. Quote Link to comment Share on other sites More sharing options...
alphadecay Posted May 21, 2006 Author Report Share Posted May 21, 2006 (edited) The other things you failed to mention is elevation and jetting. Unfortunately it sounds like you seized the piston. Quick check with the header pipe off! Our modern bikes do not make good trail bikes. My bet is your riding at elevation which is very hard on the motor. Between 02-03 gasgas slightly enlarged the oil capacity. <{POST_SNAPBACK}> Probably at about 1000ft elevation (above sea level) and stock jetting on the stock carburetor. The bike didn't seize as it did kick over, it just wouldn't start up. After oil quantity my next step will be to check the gas breather as maybe it did just suffocate and not get enough gas. Edited May 21, 2006 by AlphaDecay Quote Link to comment Share on other sites More sharing options...
totalshell Posted May 21, 2006 Report Share Posted May 21, 2006 sounds like no petrol / blockage/kink in the pipe didnt hurt the engine try and make it do it again after checking out everything listed above.. Quote Link to comment Share on other sites More sharing options...
alphadecay Posted May 22, 2006 Author Report Share Posted May 22, 2006 sounds like no petrol / blockage/kink in the pipe <{POST_SNAPBACK}> Took off the tank and checked the breather tube, didn't see any blockage and the one-way air flow connector looks to be in the correct direction and working. Only thing I see was the tube was just shoved inside the frame, it did not poke through that little opening on the underside of the frame. It seems unlikely but maybe the hose was resting on something inside and vacuum sealed against it. I'll give it a test run up the forest road again next weekend. Thanks for the input. --Tim Quote Link to comment Share on other sites More sharing options...
sherpa325 Posted May 22, 2006 Report Share Posted May 22, 2006 I have an 05 300 and mine definitely runs hot during trials, particularly if its a short lap and the sections are close together, it loses its tune and starts to rattle/pink. I have tried all sorts of fixes, petrol and jetting but I personally think the cooling system doesn't handle the extra heat generated by the 300 Quote Link to comment Share on other sites More sharing options...
uhoh7 Posted May 22, 2006 Report Share Posted May 22, 2006 I've been trail riding a bit as the snow finnally melts around here. 6-8k alt. 06 300 pro. Fan is on and off all the time. Mine did just what you described but then I changed the plug and it hasn't done it again. It also quit once after I knocked off the vent on the cap and pluged it with a stick. Pulled out the stick, let some air in the tank, and off it went. I'm often wondering "Just How Hot is it?". But the RAD never seems to loose a drop, which is more than I can say for my "enduro" bikes. Quote Link to comment Share on other sites More sharing options...
rhaines Posted May 24, 2006 Report Share Posted May 24, 2006 Make sure you dont keep constant revs on the bike when riding on roads/trails as this will lean the mix and possibly seize the piston. From what you described it doesnt sound like a fuel starvation problem as you would hear the bike rev higher as the fuel/ air mix leans out until it died. All the fluid levels sound ok so I would suspect your jetting is not quite right or you nipped the piston and thats why you had to leave it for a few minutes to cool down. Quote Link to comment Share on other sites More sharing options...
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