PW50 Rejet after Oil Injection Removal

9 replies to this topic
  • RangerCharlie

Posted April 13, 2009 - 03:48 PM


If you remove the oil injection, what do you suggest to jet to?

Bike still has stock jets, but removed the oil injection. Now bike doesn't want to idle but it does run better with premix.

I have a 62.5, 65 and a 67.5 to try.

  • CBDaddy

Posted April 17, 2009 - 06:32 PM


What did you do to remove the oil injection? Some guys say to leave everything hooked up, and just run premixed gas in the oil jug. Is that safe? Could it eventually trash the pump, or no?

  • Smacaroni

Posted April 20, 2009 - 05:51 AM


My guess is running the pump dry will fry the pump over time. Just leave it alone, it works the way it's supposed to.
My experience from the PW80 is the most power to be gained is from limiting exhaust restriction and correct jetting and you'll swear you got a whole new machine.

  • billy bee

Posted April 20, 2009 - 12:26 PM


What did you do to remove the oil injection? Some guys say to leave everything hooked up, and just run premixed gas in the oil jug. Is that safe? Could it eventually trash the pump, or no?

You can remove the pump and take the pump drive gear off the shaft. Then the pump just acts as a plug in the hole.


  • treehopper

Posted April 20, 2009 - 10:47 PM


Speaking theoretically, all of the jets would need to be bigger because the oil will be displacing about 2-1/2% of the gasoline. In practice, I think the pw is rich in the main jet department from the factory, so you would probably only have to increase the pilot jet size. That would go along with your saying that it runs better (leaned out the air/fuel mixture where it needed to be leaned out) but won't idle (leaned out the idle too much).

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  • RangerCharlie

Posted April 21, 2009 - 04:14 AM


I put in a machined plug but I am reconsidering hooking the oil back up as it seems to be running a little hot now.
The top end rebuild gave it a lot more power!

  • Smacaroni

Posted April 21, 2009 - 05:50 AM


Clean out the exhaust and dremel out any excess welds/material in the head pipe and open the air box by removing the snorkel. There's more where the top end rebuild came from.
This will make the pilot jet lean condition worse. You can try richening the idle fuel screw, but it may not be enough.

  • RangerCharlie

Posted April 22, 2009 - 04:14 AM


The exhaust port was about half closed with carbon when I did the top end and I did use a dremel to clean up the machining and such.
I also put in the Holeshot clutch springs but my daughter doesn't like it that way as she has to keep it rev'd up to keep the clutch engaged.

  • Smacaroni

Posted April 22, 2009 - 06:54 AM


I'm sure that really sucked the power down. Also check the silencer/spark arrester as that's a good place for the same stuff to build up. Don't go hacking on that though.
In the near future (two weeks?) I'll have a better low cost silencer mod that doesn't destroy the factory parts, it should work on any of the 2t kiddie bikes, cost is around $10 and about 45 minutes of work, compared to the after market silencers that are going to be $80-100 and a half-hours work.

You can put lighter springs in and it will engage sooner than stock. But not too light or it may be engaged at idle. Your daughter may prefer that.

  • RangerCharlie

Posted April 22, 2009 - 09:17 AM


I put the exhaust on the grill and cooked the crud out, it flamed for a good 1/2 hour so I guess it was loaded up in there!


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