Need help with a few questions?

[bstory1968]

#1-how do you know if you main jet is too big? I have a Tak 138 with a race head and 26mm carb. I put a 190 main and a 22.5 pilot. it seems to run fine but seems like it is getting to much gas. It did have a 170 Main and a 25 pilot.



#2-fork help. it has stock forks with heavy duty springs. My 10 year old will be racing it and the forks are too stiff even for me at 180lbs. should i just try changing the oil, or can the springs be cut a little? If they can be cut, how much do you cut? Stock spring are not enough.

[PlanetMinis.com]

[bstory1968]

Can anyone help me with these questions?

[BBR Motorsports]

# 1

Typically if your main is too big it will "surge" on top-end. And if you let of the throttle just a bit it will actually run better. When it "pops" or back fires on top-end you are too lean.



# 2

DO NOT cut your springs. This will make them much stiffer and not help with your set-up. For your lighter rider I would try one HD spring and one OEM spring with 5 or 10 wt oil, 155cc per leg. For you I would try one HD and one OEM spring with 15 or maybe even 20 wt oil, 170cc per leg.



BBR Motorsports

[bstory1968]

Thank you very much.

THis bike is for my 10 year old and he weights about 75 lbs. So use one fork with a stock spring and the other with a HW Spring? 5 or 10 wt. oil 155cc? I was told to use Transmission fluid and a lighter weight oil.

I will have him try the throttle and see if it does what you said on the top end.