Hop Ups

Discussion in '4-Stroke Engines' started by 45u, May 3, 2016.

  1. 45u

    45u Active Member

    Does anyone make hop up parts for the 4 cycle motors? My third build is going to be a 4 cycle.

  2. rhenning

    rhenning New Member

    Which 4 cycle?? There are a lot of different 4 strokes out there. Roger
  3. 45u

    45u Active Member

  4. HeadSmess

    HeadSmess Well-Known Member


    swear i have seen smaller ones...

    not much. bit of port work, can you reprofile cams, given that they use a single lobe cam? um...

    the 142f or whatever it is, isnt easily modified...looks like a huasheng, at least.
    cant raise compression ratios, cant do this, cant do that...


    modified exhaust...

    they go pretty good stock anyway. much more torque than the 2 stroke kits.

    better off sticking with a twostroke and using a chainsaw engine...
  5. Frankfort MB's

    Frankfort MB's Well-Known Member

    Could you do some port work on the intake valves and exhaust valves?
  6. chainmaker

    chainmaker Member

    Get a HF79 at least you can do some basic stuff to it, it's so small could easily pass as 49cc
  7. Nanonevol

    Nanonevol Member

  8. Frankfort MB's

    Frankfort MB's Well-Known Member

    Awe how cute :)
  9. 45u

    45u Active Member

    So what most are saying that the 4 cycle does not have anywhere near the up grades the 2 cycles do.
  10. Old Bob

    Old Bob Member

    None to speak of, small market and not enough sales to support it. They wouldn't pay $35 for a high output cam for a Honda GX series engine and there were liability issues. So it was dropped.
  11. Frankfort MB's

    Frankfort MB's Well-Known Member

    You can always go to the 212 predator:)

    I have a buddy who bought one off a guy that used to race go karts with it and it's supposed to be making 12ish HP with all the upgrades it has went through....
    He only bought it for 140$ and it looks like new with about 200-300$ extra parts on it.... It's going on a drift trike eventually:D
  12. 45u

    45u Active Member

    Want to keep it at 49cc to be legal. Would not be hard to tell the predator is not any where near 49cc.
  13. Frankfort MB's

    Frankfort MB's Well-Known Member

    Heck with a 212cc you could probably outrun the cops no need to explain that way jk jk:)
  14. HeadSmess

    HeadSmess Well-Known Member

    nope, no aftermarket parts. all you have is port and polishing, slight mods on a cam that does both exhaust and inlet valves, so could be a touch tricky... tune exhaust to the length that suits the RPM, and maybe, with a lot of searching/cross referencing, find a slightly higher compression piston.

    possibility you could relocate the rocker pivots and change rocker ratios... all DIY, no parts on the shelf to do so.

    (not sure if the smaller hondas are OHC... i think they are. never torn one apart. the huasheng is definitely a pushrod engine)

    crankcase is combined with cylinder and head, so just grinding valves is a nightmare, let alone fiddling with compression ratios, etc.

    the best thing, in my opinion? get the HT gear and clutch. get a lifan 50 cylinder, head, piston, conrod... and make up your own crankcase and shaft. then you got an overhead cam 4 stroke that bolts into a standard bicycle frame. all you need is patience, tools and some determination. obviously a project for a machinist to tackle.

    anything is possible with the right tools...