Jet

Discussion in 'The Workshop' started by pricey, Nov 21, 2006.

  1. pricey

    pricey Member

    Messages:
    113
    Hello People



    I am in need of some assistance...

    On my Suzuki Katana, I have recently fitted a new exhaust and variator,

    So i need to upjet right?

    I have a 62 or 65 jet in there at the moment and i have been told to go up to about a 90 jet.

    Is this right?



    Also the guy said that if I put a K & N filter on (which im not too keen on) and I upjet to a 110 jet then this will work fine on my bike.



    Any ideas,



    Cheers



    Also if I wasnt to upjet what would be the consequences? eg seizing?? :
     
  2. wobbly_trials

    wobbly_trials Active Member

    Messages:
    6,676
    Rides:
    RD350, SR125, ICE125
    I'm not entirely sure on your jet numbers but as a general rule, jetting should be checked and adjusted according to the individual engine each time a modification is made.



    I'm assuming by new exhaust you mean a performance one...?



    if so run the bike until its warm, ride it for about 1/2 a mile under "normal" conditions (just ride like you would on the road). Next pull the spark plug out (will be hot) and check the colour of the tip, it should be a coffee brown colour, if its black/wet the bike is running to ritch (the current jet is too big). If the plug is white or very light brown, the bike is running lean (the jet in the carb is too small).



    Jetting is a trial and error process, if the colour is pretty close then you may be able to adjust the needle height to get the bike running right (higher needle = more fuel (ritcher))



    hope this helps.



    you only need to adjust jetting for the exhaust, transmission upgrades don't affect the jetting.
     
  3. pricey

    pricey Member

    Messages:
    113


    Ok thanks Wobbly,

    I will give it a go tomorrow. :)

    Also im sure that when i changed my plug the other day the old one was wet and a darkish brown colour but i will double check. If i do have to up jet, i thought 90 was a bit too high, something like 75-80 would be better i thought.



    It just seems like it is revving its tits off when i am at full speed sometimes.

    Also the exhaust is a performance exhaust.



    My mate who does bike mechanics at college said that it would affect it but obviously not, just wanted to check.



    Cheers for the good advice :D



    This site seems much better than TAG, it is basically run by that twat PC and at least this forum gives advice, whereas TAG just takes the piss. :evil:
     
  4. wobbly_trials

    wobbly_trials Active Member

    Messages:
    6,676
    Rides:
    RD350, SR125, ICE125


    yeah, he pisses me right off sometimes, he won't give anyone a chance.



    the bike revving its nuts off is probably down the the variator rollers being too light. again i'm not sure about figures but try slightly heavier rollers.
     
  5. pricey

    pricey Member

    Messages:
    113


    Haha, there 8g rollers aswell so i don't think it will be that! They're the ones that came with the Malossi Multivar so I fitted them.

    I was going to go for lighter ones as i have terrible acceleration, probly 5g ones, would this be worse for my ped then if it will rev more? :eh:
     
  6. wobbly_trials

    wobbly_trials Active Member

    Messages:
    6,676
    Rides:
    RD350, SR125, ICE125
    did you have the spring on the torque driver behind the back pulley replaced? some multivars come with them some don't



    and also check your clutch isn't worn out.
     
  7. SimonT

    SimonT New Member

    Messages:
    601
    hey pricey...... imagine getting a response on here.....



    Anyway, i saw both this thread and the one on TAG and basically made me join here instantly.



    I dont give a crap how much PC knows.... most of the time he's an ass....
     
  8. MiNoR cOnFuSiOn

    MiNoR cOnFuSiOn Administrator Staff Member

    Messages:
    14,276
    Rides:
    et2 monster
    right, the variator on these is crap.. the jet wont be anywhere neer as high as 110 for a filter (tell your m8 to go back to college and finnish the first year befor tellying you how to rejet your bike) usually around the 75mark for a 17.5mm carb on a 50. you will always be better off running down jets from a rich mark tho (say a 90) then down a size at a time untill its perfect
     
  9. pricey

    pricey Member

    Messages:
    113


    Yer I have changed the variator for a Multivar and have fitted the torque spring behind the clutch, this made it fly when it gets to 25-30 :D



    Ok minor i will try different jets but not too high and also fiddle with different roller weights so i get a goos set-up! :ped:
     

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