Drilling Predator Jets

[jimmypadua]

Okay, i did a bit of research, reading several threads, as well as read AGK'S DIY thread on drilling jets, but as seeing that the new HF 6.5hp Replacement Predator engines are diffrent, i dont know what to do:shrug: I need to drill the jets because i installed a new custom HF airfilter and custom header , so what should i do ? What size drill bit should i use, and what size should i jet it to ?

(ill be uploading pictures of it soon)

 

[mmisterbungl]

well have you driven the bike since you did your upgrades? if so, how did the engine act? did it sputter a lot when you are taking off?

 

[jimmypadua]

Okay, i i spent some hours esterday removing the governor (yes i read governors and OldMiniBikes) so i wont go over that much. I started the motor this morning and it was a pain in the ass the start, beffore it never was that hard. Usually would start first try, but after a while, it started up and ran well idle fine, but wouldnt i need to drill it to match the increased flow ?

 

[mmisterbungl]

when you remove the G, your engine will not start as easy as it used to unless you crack the throttle open a little bit. The governor regulated all that when it was intact. You can't just pull on the engine and expect it to start exactly as easy as it used to.

In theory (based on experience with the Blue HF Clones) you would almost always have to increase the jet size. That's why I was wondering how the enine acted after you did those mods.

Oh, and if you removed the governor you will also need stiffer valve springs before you run the engine. And buy the billet stuff. I'm pretty sure this thread's gonna go on lockdown.:shrug:

 

[jimmypadua]

Yeah, i figured that i would need to throttle it to start. But why would it get locked ? I just need to know how to drill the jets, and by how i mean the size of the jet and what size drill bit i should use ?

 

[mmisterbungl]

well if you want to go off the sizes commonly used for the blue clones go with about a 37 size jet which equals to ......

I can't find these anywhere local, but get yourself some of these. Make sure you get the pin vice with it if you buy the bits separately.
Amazon.com: Anytime Tools 20 piece Tiny Small Drill Bits #61-80 Numbered Sizes High Speed Steel (HSS) Wire Gauge + PIN VISE: Home Improvement

then
http://www.oldminibikes.com/forum/h...-re-jetting-6-5-a.html?highlight=drilling+jet

 

[jimmypadua]

Alright , thanks i think this should be all i need ! I appreciate it, i think ill be able to pick up these very small bits at a hobby shop. Thanks, ill let you know how it turns out and ill post pictures laer

 

[Erok000]

Okay, i i spent some hours esterday removing the governor (yes i read governors and OldMiniBikes) so i wont go over that much. I started the motor this morning and it was a pain in the ass the start, beffore it never was that hard. Usually would start first try, but after a while, it started up and ran well idle fine, but wouldnt i need to drill it to match the increased flow ?

If it Idled fine and ran fine then I dont see the need to change the jets. You might get negative results unless its needed! Im not telling do it or not just be sure it is needed..:thumbsup: GL

OH... also the predators do use the same jets as the blu HF 6.5's, you can DIY or buy these in the size you need. again GL

 

[jimmypadua]

Yeah, true huh ? BUT , with the increased flow, and air getting into the engine, wouldnt having a richer gas/air mix, wouldnt it increase performance/power? Anyways, i might just leave it. Im glad with the mods ive done. Its scary fast to ride, and im not really looking to get racing grade speed/power. (although it would be nice.) All i need now is a better frame w/bigger wheels. What i have now works, but its so heavy and ugly, small, and etc but it works.

 

[Old Dinger]

Quote:
"What i have now works, but its so heavy and ugly, small, and etc but it works."


Did your girlfriend say that? :laugh::laugh::laugh::clap::clap::clap: Just funnin' man.

 

[jimmypadua]

Ahahaha, thats a good "Thats what she said" :laugh::laugh::laugh:

 

[Erok000]

Yeah, true huh ? BUT , with the increased flow, and air getting into the engine, wouldnt having a richer gas/air mix, wouldnt it increase performance/power? Anyways, i might just leave it. Im glad with the mods ive done. Its scary fast to ride, and im not really looking to get racing grade speed/power. (although it would be nice.) All i need now is a better frame w/bigger wheels. What i have now works, but its so heavy and ugly, small, and etc but it works.

Im far from an expert, so my advice might not be sound, but Ima speak from experience!
When I added a header to my clone( a blu one but same carbs) I was told I would need to re-jet as well. I didnt add an air filter just a header and noticed a major increase in power. It ran great, but being told I would prolly need to re-jet I ordered a few to play around with . I thought maybe I would get a gain of some sort being I opened the exhaust I could add more fuel.
I tried chngining jets and it ran like :censure:,:doah:. so I put the stock jet back in and it runs great again.
Now my neighbor got a predator and added just an air filter and it ran bad, so I let him try ona the jets I had and that fixed his problem! There is a post about it actually.
So I learned if its not needed and done youget bad results, but if its needed then by all means do it. I think if its running good then its not needed:hammer: :shrug:

GL Korey

 

[jimmypadua]

Alright, thanks. Yeah, i noticed an exponential increase in power. Although i took the governor off, that might just be what im getting power from. But i think ill just leave it alone. One day, i might get around to buying a new jet.