drz 400 sm carb flat spot

[suzuki 317]

ok, so i know that there are alor of threads on here about jetting and mods so here are the list of them from my 08 drz, yosh full titanium system, 3x3 mod, fcr slant slide off of a 01 e model, 165 main, 45 pilot, 200 air leak, ap mod with the linkage wired, (squirts across the garage) clip in the #5 slot,fuel screw out 2 turns.i have removes the anti backfire valve also.the bike flat out hauls ass compared to how it was. i live in los angeles around 400 feet above sea level. all the advice here is great and the tech tips rock! now for my problem, at cruising speed, the bike seems to surge like its lean. I am a tech with 18 years of car experience in dealerships plus lots of hot rod stuff. i know this there is a simple fix for this, just dont want to keep tearing the thing apart and guessing. any advice would be greatly appreciated...?

[DanielE]

Although my modifications are less than yours, I also experience the surging on steady throttle. Acceleration is strong and brisk, the plugs is a nice brown, and the exhaust soot is a good color. I have tried reaching down and engaging the choke a bit to see if it was a lean condition. No luck. My only guess is that it is an exhaust backwave which only ocurs at a steady throttle. I am making an appointment with a dyno guy to see what is up.

[suzuki 317]

let me know what your dyno guy says. i havent heard of any other issues on here about this problem. I rode it to work this morning and it is about annoying as hell. i cant believe that nobody else has any comments or suggestions on this. another thing i noticed this morning, the bike backfires constantly on deceleration. i put the vacuum hose between the two ports for the enrichment valve when i took it off. i thought that was supposed to remedy the bacfire issue.????? its probably something simple, i can deal with the back firing, the main thing is the surging at steady throttle.

[suzuki 317]

ok. so i get off work today expecting the bike to surge all the way home...i start it up, roll out to the street jump on it pretty hard and then find that the surge issue has all but gone away. must have missed some dirt or something when i cleaned the carb. so my suggestion to you is, remove the carb, clean the crap out of it with good carb spray and compressed air, do all the mods and enjoy. cant explain my situation but i can defenitely live with the results. tomorow...glendora mountain road here i come!