HF 2.5HP is a killer engine! New Speed Record!

Discussion in '4-Stroke Engines' started by ZnsaneRyder, Jul 10, 2009.

  1. ZnsaneRyder

    ZnsaneRyder Member

    The Harbor Freight 2.5HP engine is starting to get popular and I wanted to let you folks know this engine has LOTS of hot-rodding potential for power and light weight!!!


    Just have to mention, new speed record set by opening exhaust to straight pipe, higher-flowing intake, and removing the stock 3600RPM governor, has proven some awesome HP gains!!!

    Top speed on flat ground, now 45.3 MPH at 4800RPM!!! And this engine easily now gets to over 40mph reliably every time!!!

    And this is with a push-trailer. I imagine more speed may be possible with a frame or rack mount! It easily keeps up with average cars in city traffic! VERY NICE!

    This engine is the new Honda50 killer!!! :devilish:

    No more need for huge 196cc 6.5HP engines, when you can have a lighter, more gas efficient engine!

    We have yet to do more gas mileage testing. Stock was 140MPG, but it's now better on fuel with the engine mods, so I'll keep you posted on the next gas mileage test!

    Crazy Riding,
    ZnsaneRyder :jester:

  2. Hawaii_Ed

    Hawaii_Ed Member

    Very nice! Did not know there is a 40 MPH club! I guess I am in! Hold 43 on flat easy, have pushed over 50.

    Keeping up with traffic is a huge safety factor!
  3. 5-7HEAVEN

    5-7HEAVEN Guest

    You know guys, that'd be a nice thread...the "Over 40mph Club".

    I'm in.:jester:
  4. Rileymoto

    Rileymoto Member

    Pretty sick nasty if i do say so myself!!
  5. DetonatorTuning

    DetonatorTuning Active Member

    :evilgrin: i'm SO in.

  6. Rileymoto

    Rileymoto Member

  7. Hawaii_Ed

    Hawaii_Ed Member

    Well, that is just too good not to add it to my sig! Done!
  8. ZnsaneRyder

    ZnsaneRyder Member

    BTW, folks, this is a 79cc 4-stroke engine. Externally, it's about the same size as a Honda 50.

    Make sure to add a 2HP, 49cc sticker! ;)
    Last edited: Jul 12, 2009
  9. loquin

    loquin Active Member

    Hmmm But, Internally, about the same size as a Honda 50 AND a Honda 35 combined.

    I seriously doubt that the HP is still 2.5, after you removed the governor ... :)
  10. ZnsaneRyder

    ZnsaneRyder Member

    More than 2.5HP for sure, especially after the intake/exhaust modifications, but still small enough for the bicycle that's the idea! :jester:
    Last edited: Jul 13, 2009
  11. arceeguy

    arceeguy Active Member

    I have to disagree. Its footprint is quite a bit larger than a Honda or HuaSheng mini 4 stroke engine. It would never mount in the frame of a mountain bike or cruiser like the little Hondas. A rack mount or pusher trailer are your only choices without major frame mods.

    I do agree with you that they are kick butt little utility engines though. While mine has not seen bicycle duty yet, it powers an old Toro edger with ease. (and a lot more quiet than the B&S it replaced)

    We need to all email Harbor Freight and convince them to import the HuaSheng 4 strokes. I bet they could easily sell them for $99 and make their margin. Heck, I've gotten the big 196cc 6.5's for a little over 100 with a coupon.
    Last edited: Jul 13, 2009
  12. deck99

    deck99 New Member

    What tranny do you use or could I use with the HF 2.5 HP engine?

  13. arceeguy

    arceeguy Active Member

    A 5/8" mini bike clutch fits the output shaft. From there, you go to a reduction jackshaft and then the rear wheel.
  14. RusticoRay

    RusticoRay Member

    I've called my HF retailer once a week for a month, nothing back ordered. Anyone have any luck finding one?
  15. arceeguy

    arceeguy Active Member

    I was at my local HFT last week, picking up one of those little $99 900 Watt generators (w/coupon) for a friend and they had one 2.5 engine in stock. The box had been opened by a curious customer, but everything was there. Will your store order one for you?
  16. RusticoRay

    RusticoRay Member

    I will ask tomorrow if they could get one from another store. I'll post back there answer.
  17. deck99

    deck99 New Member

    Do you have a photo of what the clutch/jackshaft set up looks like? That seems pretty simple. Do you get the same performance as you would with like a honda motor and the grubee tranny?

  18. deck99

    deck99 New Member

    either. I prefer in frame but not sure this big motor would fit in the frame.
  19. RusticoRay

    RusticoRay Member

    HF will not order motor from another store. I could order online but how long do you think I'll get hung up waiting? deck 99 I was planning on using a 5/8 max torque belt clutch with a belt sheave off a whizzer.
  20. scdave

    scdave Member

    Deck99...Why do you prefer in frame ??