What do you think of thumb throttles on a motorized bike?

Discussion in 'General Questions' started by aquielisunari, Sep 17, 2015.

  1. aquielisunari

    aquielisunari Member

    I am thinking of dumping my twist throttle for a thumb controlled throttle and replacing the grips to something more aesthetically pleasing. A few questions... The first is the title of this post. Secondly do the thumb throttle arms automatically return to the idle position or? Lastly, while I'm trading out that(if I trade it out) I will also be replacing my stock carb. I've heard of CS1/2 carb and racing carbs. Could you please suggest a DEPENDABLE carb. Sure there aren't any guarantees in life but there are many, many opinions. I have a Grubee 66CC motor.

  2. butre

    butre Well-Known Member

    I don't like them, they screw with my carpal tunnel. if you want aesthetically pleasing and twist grips then any motocross throttle will work. thumb throttles do return to closed.

    the most dependable carb that's easy to make work is a Mikuni VM16. if you're alright fabricating an airtight plenum then I like Keihin PB clones. what problem are you having with your existing carb?
    aquielisunari likes this.
  3. aquielisunari

    aquielisunari Member

    No problem with the current carb apart from horrible gas mileage. probably around 40mpg. I expected more. I have the jet at the leanest setting. I also shut my gas off when it's not being used. BTW I am a MB newbie so no fabrication over here. Have no clue what plenum is either. Thanks for the help and time to Google plenum.
  4. crassius

    crassius Well-Known Member

    I like twist throttles - I like standard NT-style carbs, my customers that complain of poor mileage are usually just opening throttle too much - they often go uphill at full throttle without realizing that backing off about a third doesn't slow them down at all - try to match your throttle to want the motor actually needs
    aquielisunari likes this.
  5. wheelbender6

    wheelbender6 Well-Known Member

    Its personal preference. I like thumb throttles. I used an old Suntour thumb shifter. The throttle return spring is in the carburetor.
    aquielisunari likes this.
  6. butre

    butre Well-Known Member

    my bike generally wants about 90% throttle. if more air fits through your carb than through your engine then going all out isn't going to do you any good
  7. troyg

    troyg Member

    Thumb throttles are great, you can make them out of many throw away stuffs, off say a lawnmower.The bike specific ones with the heavy black snap on clip, you can spin them around and use them as a finger throttle, or move it to the left side when your hand gets tired.
  8. Hive

    Hive Member

    Simple is best most often. Twist is not so simple. Good thumb is not easy to find, but you can make an easy rig that will go to minimal when release using Sinz brake lever or similar and regular cable. Just squeeze and cruise. Never thought to way to fix in position as thought it unsafe.

    Might have to do some filing etc and some cable trim...Pic of red lever on site somewhere.
  9. Jonj57

    Jonj57 Member

    IMO the HD throttle assemblies with a (separate) alloy twister are simply and silky smooth once lubed and setup right. VERY solid, never need a hole drilled in your bars for them to stay put and the whole thing doesn't fall apart when you need to take them off just to move something around.
  10. Hive

    Hive Member

    Simple is best almost always in the beginning, and always later...it is your arse moving along...