mikeg135 Posted December 31, 2021 Report Share Posted December 31, 2021 (edited) Hello, first wanted to say what a great site. I picked up a 2009 Gas Gas 300 TXT Pro as my first trials bike and having a blast. though I am trying to work out the carb settings....it seems to smoke more than I think it should, at least compared to my other other 2 bikes(KTM and YZ125) and seems to be using more fuel than what I expect. Just playing around the yard with 1/2 idle and 1/2 clearing it out with modest throttle( no more than 1/2 throttle) it seems to burn about 40oz of fuel in a 15-20 session. it has plenty of power. I am at 350ft above sea level and has the following settings which is how I received it: Dellorto Carb 118 Main, 35 Pilot, D36 Needle in the leanest position (clip in highest position), and fuel screw at 2 1/4 turns out. Air filter has been serviced and plug is a tad oily. Fuel: fresh non-ethanol 93 octane & Belray H1R at 80:1 Any ideas? or is the smoking and fuel burn seem average? Bike does seem to run well, just smoky and will load up after a minute of so of slow turns and figure 8s. Edited December 31, 2021 by mikeg135 Quote Link to comment Share on other sites More sharing options...
zippy Posted December 31, 2021 Report Share Posted December 31, 2021 Check your transmission fluid level, if you have a leaking clutch side crankshaft seal it will suck in trans fluid and burn it causing excess smoke. Not sure on fuel consumption, I never measured, just rode it and filled up when necessary. 1 Quote Link to comment Share on other sites More sharing options...
mikeg135 Posted December 31, 2021 Author Report Share Posted December 31, 2021 12 minutes ago, zippy said: Check your transmission fluid level, if you have a leaking clutch side crankshaft seal it will suck in trans fluid and burn it causing excess smoke. Not sure on fuel consumption, I never measured, just rode it and filled up when necessary. Thanks for the reply. I does seem ok, maybe a little high through the glass. I will keep an eye on that. I would imagine changing that seals doesn't require splitting the cases just removing the side cover, clutch and primary gear to access it. Quote Link to comment Share on other sites More sharing options...
lineaway Posted December 31, 2021 Report Share Posted December 31, 2021 Make sure the choke is all the wsy off. Straight up is choke on, down is off but it can get stuck out of its groove and still be barely open. 1 Quote Link to comment Share on other sites More sharing options...
mikeg135 Posted December 31, 2021 Author Report Share Posted December 31, 2021 23 minutes ago, lineaway said: Make sure the choke is all the wsy off. Straight up is choke on, down is off but it can get stuck out of its groove and still be barely open. didn't think of that...I had the carb off yesterday to verify the jetting and clean it....but didn't remove the choke assembly though. over all everything look pretty clean inside the carb with no noticeable signs of neglect. But I will take a closer look to ensure its going up and down fully 1 Quote Link to comment Share on other sites More sharing options...
Glayne Posted December 31, 2021 Report Share Posted December 31, 2021 +1 to the choke on, I have rode an embarrassing distance a few times not noticing the choke on! If your not using more than half throttle the fun factor can pull the wool over the troubleshooting part of the brain. My excuse would be riding with the kids...more concerned about them...I see 40 oz as a lot to consume in 20 mins whether it be beer whiskey or premix fuel! Side story, raced a hair scramble about 15 years back and one of the faster riders accused someone of pulling his choke on the starting line. He raced over AN HOUR WITH THE CHOKE ON!!! and I believe DNF'd after 2 of 3 laps. FASTER RIDER...AN HOUR...RACE!!! Quote Link to comment Share on other sites More sharing options...
mikeg135 Posted December 31, 2021 Author Report Share Posted December 31, 2021 33 minutes ago, Glayne said: +1 to the choke on, I have rode an embarrassing distance a few times not noticing the choke on! If your not using more than half throttle the fun factor can pull the wool over the troubleshooting part of the brain. My excuse would be riding with the kids...more concerned about them...I see 40 oz as a lot to consume in 20 mins whether it be beer whiskey or premix fuel! Side story, raced a hair scramble about 15 years back and one of the faster riders accused someone of pulling his choke on the starting line. He raced over AN HOUR WITH THE CHOKE ON!!! and I believe DNF'd after 2 of 3 laps. FASTER RIDER...AN HOUR...RACE!!! haha, yeah I am nearly 50 and still a bit apprehensive these days after a gnarley mountain bike accident last year put me in the hospital with a broken collar bone, 5 broken ribs and a collapsed lung. I got hooked farting around the yard on a trials bike after a couple of friends let me ride theirs at Barbers Vintage festival this past Fall. The choke lever is definitely in the down position(off), is it possible on the Dellorto carbs for it to be slightly open even if the lever looks to be fully down? That is the one part that I didn't take apart to clean when I had the carb off yesterday. Quote Link to comment Share on other sites More sharing options...
sherpa325 Posted January 1, 2022 Report Share Posted January 1, 2022 Sometimes if the bike hasn't had a decent amount of high speed or hard throttle use, the exhaust gets deposits of carbon which tend to smoke as the bike heats up, particularly if it's been run on a high oil/fuel mix. 1 Quote Link to comment Share on other sites More sharing options...
mikeg135 Posted January 1, 2022 Author Report Share Posted January 1, 2022 (edited) 1 hour ago, sherpa325 said: Sometimes if the bike hasn't had a decent amount of high speed or hard throttle use, the exhaust gets deposits of carbon which tend to smoke as the bike heats up, particularly if it's been run on a high oil/fuel mix. I am really hoping this is the case.....the previous owner didn't have the bike long....but for the couple of months he had it he ran race fuel with Castor 927 at 32:1. The first time I got it hot after mixing in some regular pump 93 octane to bring the overall ratio to 80:1 the exhaust core got cherry red and started throwing sparks. I didn't run it long like that and have since repacked the muffler. It hasn't done that again with just pump fuel and Belray H1R at 80:1 and the plug is definitely still pretty black with no signs of grey, white, or brown coloration. I read the exhaust can do that if there is a significant amount of unburnt oil in the middle box. I think what just has me a tad worried is that the needle is at the leanest setting with the fuel screw 2 1/8 turns out and it still feels since it feels boggy and definitely more smoky after some short low rpm drills along with the what seems like higher than normal fuel use. I have worked on and carbs before, but never a dellorta. My current settings just seem a bit off compared to what I have read should be normal. Edited January 1, 2022 by mikeg135 Quote Link to comment Share on other sites More sharing options...
faussy Posted January 1, 2022 Report Share Posted January 1, 2022 (edited) Jetting and needle are standard for the dellorto, but as you say the needle is usually in the middle position Edited January 1, 2022 by faussy Quote Link to comment Share on other sites More sharing options...
gasgasman280- Posted January 2, 2022 Report Share Posted January 2, 2022 I would put a lot of money on the exhaust being totally clagged up. A bike that old is guaranteed to have it's central exhaust box full of carbon and unburnt oil. Quote Link to comment Share on other sites More sharing options...
mikeg135 Posted January 2, 2022 Author Report Share Posted January 2, 2022 took everything apart again tonight...verified the weight of the floats, removed every single component: jets, atomizer, choke, needle/seat, and filter screen. set need to second from the bottom, which I believe is the factory setting for sea level(D36 needle has 4 positions) and started with 3 turns out on the fuel screw....bike started up like normal. had a deeper tone to the exhaust and it actually felt like it had a little more grunt off idle. smoking seems to be about the same so as long as it appears to run normal, I am just going to ride and enjoy it and just realize that I won't be able to do any of the 12 mile trail loops in our area on the bike unless I get a larger tank. if I start fouling plugs relatively easily then I will revisit this issue....cheers and thanks everyone for the tips Quote Link to comment Share on other sites More sharing options...
mikeg135 Posted January 2, 2022 Author Report Share Posted January 2, 2022 53 minutes ago, gasgasman280- said: I would put a lot of money on the exhaust being totally clagged up. A bike that old is guaranteed to have it's central exhaust box full of carbon and unburnt oil. I saw a video of someone using a heat gun to cook out the middle box...is that the normal process Quote Link to comment Share on other sites More sharing options...
Glayne Posted January 2, 2022 Report Share Posted January 2, 2022 (edited) 12 hours ago, mikeg135 said: took everything apart again tonight...verified the weight of the floats, removed every single component: jets, atomizer, choke, needle/seat, and filter screen. set need to second from the bottom, which I believe is the factory setting for sea level(D36 needle has 4 positions) and started with 3 turns out on the fuel screw....bike started up like normal. had a deeper tone to the exhaust and it actually felt like it had a little more grunt off idle. smoking seems to be about the same so as long as it appears to run normal, I am just going to ride and enjoy it and just realize that I won't be able to do any of the 12 mile trail loops in our area on the bike unless I get a larger tank. if I start fouling plugs relatively easily then I will revisit this issue....cheers and thanks everyone for the tips 12 miles would be around max for my 280, an extra fuel bottle 24oz sure adds some confidence. But it does have the Keihin carb. Edited January 2, 2022 by Glayne Quote Link to comment Share on other sites More sharing options...
lineaway Posted January 3, 2022 Report Share Posted January 3, 2022 So since you have done everything, again. How are the vent lines routed? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.