glennp Posted February 26, 2013 Report Share Posted February 26, 2013 Just bought a 2011 txt 300 with less than 20 hours of use and it starts fine cold, but not when it's hot. I can bump start it and it runs fine. I have read some posts suggesting a spacer on the head and bigger jets. I have not changed the plug or anything yet. I'd like to start with the easy fixes first... Thanks! Quote Link to comment Share on other sites More sharing options...
mr neutron Posted February 26, 2013 Report Share Posted February 26, 2013 This does sound like somewhat of a jetting issue to me. Does it start well with choke on, or possibly off? Does it run well otherwise? Have you fiddled with your low throttle mixture (or fuel screw) screw? The low speed mix circuit is a cheap (as in NO COST) area to work on. It'd be nice if it were simply something like an idle adjustment; that would make your life easier. Float level is another area that may possibly be worth looking into, but I kinda doubt if that will solve your "easy cold start/hard hot start" dilemma. Your reed petals' condition might be worth looking intos, as well..... If your carb on your 300 is a Keihin, screw your idle air mixture screw inwards (lightly) until it bottms out (lightly), then screw it out 1 turn. This is probably a good general starting point. Every Keihin carb I've ever had specified 1-2 turns out, and this has always worked for me, provided the pilot jet was correct. It's an air screw for the idle circuit, so screwing it in will give the bike less air at idle/very low throttle openings (makes the mixture richer), and screwing it out makes it get more air (makes it leaner) at those same throttle settings. If it's a Dellorto, I don't have as much experience with as I do Keihins. I do know that the what I call the idle mixture screw is actually a "Fuel Screw", and as far as turns in & out, it works the opposite of the Keihin. Screwing it in meters less fuel (leaner mixture), and screwing it out makes it richer, again, at idle/slightly above idle throttle openings. I guess it's typically around 3 & 1/2 turns out, again, if the jets are good. Here's a link to a video that deals with the Dellorto carb. He (Jim Snell) begins talking about the fuel screw at about the 19:00 minute point in the vid...... http://www.youtube.c...&v=1EbXacjIV78#! Hope this possibly helps. Please let us know how it works out. Oh yeah, did you possibly attend the trial at Dallesport, WA, a couple of weekends ago? It was put on by COTA, the local trials club. It was a dry, nice sunny day, but did have a little bit of wind... Anyway, there are a couple of guys in the club pretty sharp with Gas Gas bikes, and they can definitely give ya even more help than I'm able to.... Jimmie Quote Link to comment Share on other sites More sharing options...
digger144 Posted February 26, 2013 Report Share Posted February 26, 2013 it really is a knack starting the 300 pro, you soon get used to it, there have been previous posts on this subject Quote Link to comment Share on other sites More sharing options...
sting32 Posted February 26, 2013 Report Share Posted February 26, 2013 (edited) Jetting being towards being lean makes the bike SNAPPY, but harder to start warm, (IIRC) so might check what other people near you have for jets. Also kehin VS Delorto use different jet numbers I believe. Plain pro's and econo have dellorto's on them. Race and Raga's have Kehins. Also NOTE, one of the 2 carbs is more "touchy" about opening the throttle during kick, I think it is the Dellorto, come to think of it. But maybe others wil chime in, I think I haven't had a dellorto carbed 300 in several years now, I have the '11 Raga, and starts nice, my dad put the different (lower compression) head insert (race and Raga, come with a removable head "insert" that you can change compression relatively cheaper and easy, unless you think putting 2 more o-rings & a copper gasket, they sell in kit form, that is INEXPENSIVE, into the job of putting the head back on, is easy enough). Seems easier to kick, not a lot taken off the bike power wise, on his 12 Raga. everything about starting the PRO is about the kick, especially the 300's and even more if you have the available HI-COMPRESSION head insert on it. Edited February 26, 2013 by sting32 Quote Link to comment Share on other sites More sharing options...
glennp Posted February 27, 2013 Author Report Share Posted February 27, 2013 Good information! Thank you. Once or twice I choked it when it was hot and it started. Going to look up the secret txt starting procedures, then fuel air screw, then jetting. I got the bike a few days after the dallesport event. I did ride there on my first day and I could still see every section... Quote Link to comment Share on other sites More sharing options...
mr neutron Posted February 27, 2013 Report Share Posted February 27, 2013 (edited) Hmmm, well, it sounds like it could a be a bit richer for your idle circuit then, it the choke helped starting after the bike is warm. I've read that the manufacturers sometimes send them here jetted a little bit lean, but don't know that for certain. I know there's no way a manufacturer could possibly have them jetted perfect for all the places their bikes get shipped to..... I think you're on the right track; try adjusting the idle mixture fuel/air screw (what carb is on that bike?), and go from there. My bike seems jetted to perfection (previous owner got it dialed in that well), but the Dellorto carb it has DOES NOT LIKE to have the throttle cracked open the least bit when starting, until after it fires. Hot or Cold, it's like that.... So, yeah, try to get your mixture dialed in, learn the "routine" your bike wants for starts, and have fun on it! I envy ya being that close to that riding area, GlennP. I hope to make it out there for some practice in a month or so. I know riding in the rain & mud on this side of the hills will make a guy a good rider. But I've grown tired of the mud. It's nice to have some "dry fun" every now & then..... Are you planning on riding any of the COTA events? Are there some good trials areas at the HRC Forest trails, like maybe somewhere out of Post Flats, or any of the other staging areas? Jimmie Edited February 27, 2013 by mr neutron Quote Link to comment Share on other sites More sharing options...
glennp Posted March 1, 2013 Author Report Share Posted March 1, 2013 Jimmie, I have some insane trials circuits in the gorge. I carry extra gas and do 20 mile rides. If you want email Glenn at gorge dot net. Going to tinker on my bike tomorrow and ride it after... Quote Link to comment Share on other sites More sharing options...
glennp Posted March 4, 2013 Author Report Share Posted March 4, 2013 I cleaned the carb and adjusted my fuel screw from 2 3/4 turns to 3 1/2 turns. Reved better but still hard to start. I then put in a new bpr5eix plug in and used the following starting procedure: Put the bike in 2nd or 3rd Push back with the clutch out until the rear wheel stops Engage clutch and kick Seems to work! All the Japanese bikes and ktm 2 strokers start first kick unless the bike has been upside down for a bit. Not sure why GG hasn't fingered it out... Quote Link to comment Share on other sites More sharing options...
mr neutron Posted March 5, 2013 Report Share Posted March 5, 2013 Yeah, my old KTM 300 MXC was a good starter like you described too. My 2010 280 has pretty much been a "2 kick" starter when cold, and 1 when warmed up. But, I can't crack the throttle the least little bit. It has to be shut. And kinda like you described, I have to push on the kickstart lever until it just goes past tdc/compression slightly (which isn't always easy to do with the kicker), then "fall back" like Jim Snell show in his "How To Start A Trials Bike" video.... I just finished up installing my S3 Low Compression Insert in the bike's head, along with repacking my silencer. Object was to have an easier bike to start, and one that was slightly quieter. I succeeded only on the starting part. The reduced compression does indeed make it easier to push the starter lever around, and I haven't yet noticed any power loss. I have to "re-repack" my repacking job on my silencer, however, It's louder now than it was before I decided to "fix" it..... Glenn. I'd like to get ahold of ya and get a ride in there at HRC some day, if you don't mind. Just want my bike kinda dialed in before I do that, and I probably should let my knee heal up a little more before I go on any long rides. You plan on going to the trial at Washougal this Sunday? I might go watch that..... Jimmie Quote Link to comment Share on other sites More sharing options...
sting32 Posted March 11, 2013 Report Share Posted March 11, 2013 GlennP... The main reason the bike is hard to start, compared to "Japanese" bikes in general, is the "UBER LIGHTWEIGHT" design of this particular bike, and OSSA as well. you have only just over 45 degrees of rotation to light the bike off, where on some bikes I have, you have 180 degree of kick shaft movement, helps a bunch. plus more people I watch trying the Gas Gas for the 1st time are lazy kickers, and you cannot be one. You have to use your legs not body weight to accelerate your kick. there are tips and tricks already posted for starting a pro, you just have to look around. Neutron says it like it is. :thumb Quote Link to comment Share on other sites More sharing options...
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