Another jetting ?

Thinking about going with a clamp on pod type air filter on a stock crf50 with stock pipe that has a Pit King exaust tip on it. Do you think I can get buy by just raising the needle or should I go up one size on the main jet?

Thanks Mini

Hopefully some one that performed a similar mods can give you their actual jet sizes. I have an essentially stock airbox with a minor pipe mod and I moved the clip down one and use a #62 main jet. I would guess that your pod mod would loose a little low end if you don't go with an over bore kit. I believe you will need go up more than one jet size, I would recommend trying a #68 if you can find one for the stock carb. I would also suggest a timing adv CDI to help with throttle response.

I would go with the K&N. It worked great for me when I had a stock motor.

Thinking about going with a clamp on pod type air filter on a stock crf50 with stock pipe that has a Pit King exaust tip on it. Do you think I can get buy by just raising the needle or should I go up one size on the main jet?

Thanks Mini

Stay at the stock main #58. Put the clip in the middle. Run the pod, and the stock end cap with the spark arrestor cut off internally.

Not rocket science, the tuning potential of a stock Fiddy IS NOT unlimited.

I agree it's not rocket science, but I would not do the mod you suggested. Most sights do not recommend cutting off the spark arrestor on a XR50 and with essentially stock jetting plus a pod filter the bike will run too lean.

I agree it's not rocket science, but I would not do the mod you suggested. Most sights do not recommend cutting off the spark arrestor on a XR50 and with essentially stock jetting plus a pod filter the bike will run too lean.

I run a Crower ported head, Five O pipe, TB 88 kit, Kitaco super coil and Crower .224 HT cam with the stock carb with UNI pod (58, 1.75 turns, middle clip, choke mod) for MX and the plug is perfect. Makes 4.5 HP and same torque on the dyno. For supermoto I run a 20mm Mikuni that has the motor making 6 HP and 4.5 torque.

Your Pit King end cap is robbing your engine of what little torque it has, by not allowing the motor to make backpressure.

Want a great running stocker?

Mod the pipe like this: Run a Powroll Thrust Nozzle or just cut off the spark arrestor internally, use a 1" hole saw and cut out the screen in the pipe. It'll flow better and still make backpressure.

Run a UNI pod, not a K&N.

Advance the timing ala www.50mods.com...........

Pull the choke and plug it with a Joker Machine Plug.

Run stock main, middle clip and get the fuel screw right.

Run name brand 87 octane fuel.

That's as good as it'll get stock, going fatter on the main will only make your plug nice and fuzzy black.........

(SNIP) Mod the pipe like this: Run a Powroll Thrust Nozzle or just cut off the spark arrestor internally, use a 1" hole saw and cut out the screen in the pipe. It'll flow better and still make backpressure.

(SNIP)........

One question on the pipe mod -

I understand the part about cutting off the spark arrestor screen on the stock end cap, but what is the 1" hole saw for?

Does the stock cap, without the screen (straight-shot through the cap), give the right amount of backpressure for the stock motor?

Thanks - Jay

Thanks for the info everyone

jvxrz:

The 1" whole saw is to remove the perforated screen in the middle of the stock exhaust pipe, don't modifythe exhaust spark arrestor.

jvxrz:

The 1" whole saw is to remove the perforated screen in the middle of the stock exhaust pipe, don't modifythe exhaust spark arrestor.

I didn't know there was another screen inside the pipe - I thought the usual mod was to the end cap.

I removed the screen on the end cap.

Is removing the internal screen the better exhaust mod? :naughty:

Jay

I am happy with the mod and borrowed the idea from this web site:

Exhaust Mod

Also, as someone stated in an earlier post, it's best to move the needle clip down first and then adjust the main jet size if needed later.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now