Advice needed for setting up a Yam Jog R with 70cc big bore

Discussion in 'Scooter Tuning' started by chopper3434, Mar 6, 2011.

  1. chopper3434

    chopper3434 New Member

    Messages:
    4
    Hello, I'm new to all this tuning and I'd be gratefull for any advice. I've just fitted a Italjet 70cc bigbore kit {cast iron} and I've also fitted a Amtrak variator and a Doppler air filter. questions I'd like help on are
    1, The variator comes with three sets of rollers, I've fitted 4g ones at present. The kit has 3.5g, 4g & 5.5g in the kit, which would you say would suit best. {i'm 11 stone in weight}
    2, I need to jet up the 38mm Dellorto carb, 65 jet is in it at present. What would you go upto?
    3, What increase in power should I expect from these mods, its running a Viper exhaust, are these any good.
    4, last Question, The variator kit come with a big spring for the hub on the rear wheel drive but I cant undo the bloody nut, I've tried the back brake on and a impact wench, any idea's

    any help would be great.

    Chopper :beg:
     
    chopper3434, Mar 6, 2011
    #1
  2. tErr0

    tErr0 Administrator Staff Member

    Messages:
    5,816
    Re: Advice needed for setting up a Yam Jog R with 70cc big b

    4g rollers sounds too light for a cast iron sport kit.

    38mm carb? I think not. If you really do have a 38mm carb and you are not completely confused then chuck that away and find a proper sized carb. From 17.5mm to 21mm should work fine.

    With that 70 kit you should be looking at double the power of a stock bike. Read this guide to understand power in relation to speed http://www.scootershack.co.uk/scoot...cooters-dont-go-90-100mph-t21819.html#p230431

    Viper exhausts are pretty terrible but with a sport 70cc kit it's not the end of the world. You probably wouldn't get much noticeable difference buying a better exhaust.

    The spring you are referring to is the Contra spring. It's inside the clutch assembly. You have to remove the whole unit to change it.
     
    tErr0, Mar 6, 2011
    #2
  3. chopper3434

    chopper3434 New Member

    Messages:
    4
    Re: Advice needed for setting up a Yam Jog R with 70cc big b

    My fault with the carb its a stock jog R dellorto. I am struggling to get the assembly off for fitting the contra sping, any ideas. Wouild the 5.5g rollers be better ????
     
    chopper3434, Mar 7, 2011
    #3
  4. tErr0

    tErr0 Administrator Staff Member

    Messages:
    5,816
    Re: Advice needed for setting up a Yam Jog R with 70cc big b

    What are you struggling with? Removing the rear pully or splitting the clutch?

    Use this guide to help you setup your bikes rollers http://www.scootershack.co.uk/rollerguide.html
     
    tErr0, Mar 9, 2011
    #4
  5. chopper3434

    chopper3434 New Member

    Messages:
    4
    Re: Advice needed for setting up a Yam Jog R with 70cc big b

    Right, I've done all the mods regarding fitting the 70cc kit, I have upjetted the carb to a 94 and the plug is a nice coffee brown colour. the variator is in, I fitted the 4g rollers first but then went to the 5.5g one as advised, these are better, the bikes more progressive rather than all at once. The thing I'm trying to do now is remove the bell housing on the clutch assembly to fit the contra spring. The nut won't budge. I've tried using the back brake and also locking the wheel using a bar through between the belt casing and exhaust assembly {ouch}.

    Could I use a big fuck off pair of stilsons to hold the bell housing whilst undoing the nut ?????

    Another bit of advise I need is, If i've increased the cylinder bore to 70cc, do I need to alter the autolube. I have been putting a cap full of oil in the tank when filling it up to be safe ????

    Last one, The shitty viper exhaust, is it restricted in any way ???


    Thanks for all your help,

    Chopper
     
    chopper3434, Mar 12, 2011
    #5
  6. eddo241

    eddo241 Member

    Messages:
    129
    Rides:
    NEOS
    Re: Advice needed for setting up a Yam Jog R with 70cc big b

    i just take off the nut with an electric gun
     
    eddo241, Mar 13, 2011
    #6

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