Jetting info DRZ400S TMR40-36 carb

Discussion in 'Technical' started by bill, Jul 10, 2007.

  1. Does anyone have info re jetting of the Mikuni TMR40-36 flatslide carb when fitted to a stock Suzuki DRZ400S

    I bought my DRZ here in Cambodia and had the Carb and FMF muffler transfered from another bike.

    I am now opening up the airbox (3x3 hole) and adding an FMF Powerbomb header so expect I will need to rejet, bigger main jet at least.

    There's a few DRZ's running around Cambo with the TMR40-36 carbs but no one that I know of has any jetting info .

    tried Thumpertalk, no-ones heard of them

    I suspect there's a few DRZ's in Thailand with the TMR40-36 as well so would be interested to know what jetting others are running with hi flo aftermarket exhausts.

    My current setup is
    main jet 155
    pilot jet 27.5
    needle clip second from top.
    Stock header, FMF Q muffler
    recent 3"x3" hole cut in top of airbox (as per thumpertalk recommendation)

    With the opened up airbox and planned new FMF header, I suspect I will have to go 160 or 165 mj

    Comments, suggestions ??
  2. Yeah, TT's a great forum and I've got some good info off there but no luck with info on the TMR carb. Had plenty of exchanges with Eddie, the resident TT jetting expert, he's aware of them, but doesnt use them because, surprise surprise, he cant get jetting info on them lol.

    They are used sometimes on KTM's ,Husky's, and ATV's plus Yoshimura produces a racing DRZ with a TMR-MJN carb and has the TMR carb in some of their other kits, but still no jetting info.

    Anyway, Ive ordered a couple of bigger main jets with my new header so should be able to sort it out with trial and error..
  3. Just do it the old fashion way
    Start with the main jet and work back.
    Do a plug chop at full throttle, pop the plug out and let it tell you whats going on, if you dont know how to do a plug chop here is what you need to do.
    Take your bike and some tools some where your not going to piss any one off, a nice straight flat road.
    Take off and shift up to 2nd and hold the bike flat out at full revs for about 5 seconds, let it wind right out and hold it, now comes the tricky bit. Shut off the throttle, pull the clutch in and hit the kill switch all at exactly the same time, bring your bike to a stop not allowing the engine to turn over at all, so wait till you have come to a complete stop before letting the clutch back out, take out the plug and read what colour it is, thier are plenty of web sites about reading plugs but the general rule of thumb is White or very light in colour: too lean, bigger main required
    Black or dark in appearance too rich, smaller main required, Tan in colour, the right mixture is achieved.
    Before attempting this put your needle back to its standard centre position, after you have achieved the correct main jet then you can go back and start doing chops again at half throttle to achieve the ultimate clip position, put a mark on your throttle grip at half throttle so you know where to hold it open at. But if you get the main right it should (not all the time but most of the time) the mid range should be fairly right in its standard position. After all that then you can start looking at the pilot jet, you could attempt a plug chop at about 1/8th throttle but if you find that you are winding your mixture screw too far out or too far in that could mean that you might have to look at a different size pilot
    Hope this helps
  4. Jesus Jon you stole that off me after trying to get that dog of a steed running!

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