Harbor Freight 2.5hp torque specs

Discussion in '4-Stroke Engines' started by sdp, Dec 2, 2010.

  1. sdp

    sdp New Member

    I've already printed the manual for this engine from the Harbor Freight website. Anyone have the torque specs for the connecting rod bolts, side cover bolts, cylinder head bolts and flywheel nut?
     

  2. loquin

    loquin Active Member

    I'll verify an email that I received from them, but I believe the side cover bolts are supposed to be at 25 foot-pounds.
     
  3. sdp

    sdp New Member

    I've emailed Harbor Freight for this info and have not heard back from them. The side cover bolts for the bigger GX160/200 engines only get torqued to 17ft-lbs. So 25ft-lbs sounds a bit high. If you have an email from them I would to see what info they provided.
     
  4. professor

    professor Active Member

    Small block chevy rods get 35, so I think some stripped bolts will be the booty at 25 foot pounds.
     
  5. loquin

    loquin Active Member

    max torque depends on bolt grade, bolt size and pitch...

    I had mis-remembered the source. The email from HF tech support was in regards to the engine torque.

    I had to replace the crankcase cover under warranty (It had a casting defect and had a slow oil leak)

    When I ordered the replacement parts at HF's support line, I asked them about the crankcase cover bolt torque; they did not have the info, but checked with the factory, and called me back later and left a message with the info; I just checked my manual, where I had written it down, and per HF tech support, the torque IS 25 foot-pounds, for dry bolts (no lubrication.)

    When I tightened mine down, by the time I got to 20, it 'felt' awfully tight, so I didn't take them all the way to 25.

    Per the torque table at cncexpo.com, ISO 10.9 rated 8mm bolts can be torqued to 27.5 foot-pounds. For ISO 8.8 rated bolts, though, the max should be 18.75 ft-lbs.

    However, you said 'side cover bolts.' Are you talking about the bolts for the sheet metal cover for the pull starter, or for the crankcase cover casting? The sheet metal bolts are only 6mm, and they should be torqued to no more than 7.7 ft-pounds for ISO grade 8.8 bolts, or to 11 ft-lbs for ISO grade 10.9 bolts...
     
    Last edited: Dec 19, 2010
  6. sdp

    sdp New Member

    I was talking about the crankcase cover. I pulled the govenor out of this motor and was wondering if anyone had the torque specs for the side cover. I ended up going with 9ft-lbs which is the torque spec from a similar Honda engine.

    We are going to put this motor in one of our bikes to get a baseline. Then the motor is will be taken apart for some performance mods. We'll just use the torque specs we have for Honda engines of similar size until Harbor Freight can provide us with something different.
     
  7. loquin

    loquin Active Member

    Do the Honda engines have the same size (and number of) bolts?
     
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