Damnit Bob Posted June 9, 2010 Report Share Posted June 9, 2010 I ride a stock cylinder aggressive dune port 4mil, 35mm kiehins, +4 timing on 50/50 with 21cc domes and 10paddle haulers 72in ro and I am just getting into sand drags, and i cant seem to launch in 2nd gear effectively. I generally run better races when i launch in 1st but i know i am not getting full potential out of my quad. When i launch in 2nd I either need to burn my clutch for seemingly way way too long, or i just bog out completely even when throttle is pinned before the drop. Can somebody give me some advice? do i need to change my setup? I am frustrated running too close with JD's (87sheerips) stock stroke trail bike. Quote Link to comment Share on other sites More sharing options...
sheefreak Posted June 9, 2010 Report Share Posted June 9, 2010 What gearing are you running Bobby and where is your jetting at(particularly your pilot, needle, and airscrew)? Quote Link to comment Share on other sites More sharing options...
Damnit Bob Posted June 9, 2010 Author Report Share Posted June 9, 2010 Gearing is 15-41 for now (thinking about going to 14 in front), jets are 160/58 and air screws are 2.5 out (i think) not sure about needle. I was going to go home today and start tuning/messing with the carbs Quote Link to comment Share on other sites More sharing options...
sheefreak Posted June 9, 2010 Report Share Posted June 9, 2010 You may be a hair tall on the gearing w/72 rollout tires and a 15/41. Granted, I am pretty sure I can throw more gear at my bike, but that is what I run on my 10 mill alky bike. If the bike seems to run clean in the midrange and plugs aren't soaked or black looking I would mess w/your gearing. 15/43 would be a good try or perhaps a 14/40...somewhere in that ball park. Quote Link to comment Share on other sites More sharing options...
alf44 Posted June 9, 2010 Report Share Posted June 9, 2010 Typically u want your air fuel screws out 1 1/2 turns. Im still running stock gearing on my new 4mill build. Ive been considering going to a 15/42 or 44 setup. If your carbs arent dialed in right your going to have some bog on the launch. Have u tried running straight race fuel and not mix it. I no I had my domes cut to run race gas and have 185psi. I no our elevation is alot different but I would mabey start playing with your pilot jet or moving your clip up a notch or two. I fought and fought a similar problem. Finally a raised my clip up to the top and it was all the difference. I would try both senarios. raise it up and drop it down and see where your at after that. Quote Link to comment Share on other sites More sharing options...
sheefreak Posted June 9, 2010 Report Share Posted June 9, 2010 I do agree that if you are rich in the low/midrange it will also cause you to bog at launch. Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted June 9, 2010 Report Share Posted June 9, 2010 Do you have a 58 or a 48 pilot? If its 58 that seems really big to me. I'm running a similar setup with 48/158 on 35 PWKs Quote Link to comment Share on other sites More sharing options...
Damnit Bob Posted June 9, 2010 Author Report Share Posted June 9, 2010 When i checked compression after the build, i was below 150psi (like 140ish if i remember right). I ran with 93 for a while because i had some mixed already and was having trouble with backing off plugs, i tried full 110, but i felt it was not what it should have been, i landed on 50/50 and it seams to be better. I tried the 1.5 out on my air screws, but it wouldn't idle for more than 15 or 20sec. I guess that should have been my first clue to change the needle position but i went the easier route. I will try the need position first when i get home. I have a few gears to play with too. Do you guys think its more bike set-up, or riding style? Quote Link to comment Share on other sites More sharing options...
Damnit Bob Posted June 9, 2010 Author Report Share Posted June 9, 2010 Do you have a 58 or a 48 pilot? If its 58 that seems really big to me. I'm running a similar setup with 48/158 on 35 PWKs its 58, low end does seam alittle rich, but the plugs look about perfect. Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted June 9, 2010 Report Share Posted June 9, 2010 What brand compression tester are you using? Those are 21cc 4mil domes right? With my Craftsman tester I was around 168 with 21cc 4mil domes. Also you didn't say if you had 48 or 58 pilots Quote Link to comment Share on other sites More sharing options...
hercalmighty Posted June 9, 2010 Report Share Posted June 9, 2010 Never mind. I guess we were posting at the same time. I may be wrong but I would ask other guys around you what they are running for pilots Quote Link to comment Share on other sites More sharing options...
banshee(911) Posted June 9, 2010 Report Share Posted June 9, 2010 (edited) i ran 14/43 gearing for 300 with inframe pipes and a 4 mill cub this year im running 14/44 with oof pipes hope this helps Edited June 9, 2010 by banshee(911) Quote Link to comment Share on other sites More sharing options...
pr0blumz Posted June 9, 2010 Report Share Posted June 9, 2010 (edited) its 58, low end does seam alittle rich, but the plugs look about perfect. I had a bog like you described and had to jet down 3 sizes on the pilot. Edited June 9, 2010 by pr0blumz Quote Link to comment Share on other sites More sharing options...
firebanshee Posted June 10, 2010 Report Share Posted June 10, 2010 Gearing is 15-41 for now (thinking about going to 14 in front), jets are 160/58 and air screws are 2.5 out (i think) not sure about needle. I was going to go home today and start tuning/messing with the carbs I think you are geared to high.15-41 is what i run on my 72 rollout tires on my 421 cub on alky.I would drop 1 tooth in front.Try it you will like it.How long of swingarm do you have? Quote Link to comment Share on other sites More sharing options...
RadarRacing Posted June 10, 2010 Report Share Posted June 10, 2010 I agree with the pilot 100% go down to a 48 or 45. Also your gearing is quite a bit too high for a second gear launch with what you have tire/motor etc. I'd run stock gearing 14/41 or even a little lower like 42/43 in the back. It will still run 70-80 mph in 5th with lower gearing. Quote Link to comment Share on other sites More sharing options...
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