2hp flat top briggs im trying to detonate spectacularly

L

leakyhead

New member
Hello Guys, I have a 2 HP briggs aluminum bore(1975ish) that i ended up with on a mini bike . I bought the engine to teach my son and a friend how the engines work but unbeknownst to me it was running so after riding i, the bug has bit me again. I am somewhat very mechanically inclined, i have all fab and cnc machining capabilities. So, I can afford to buy a new hot rod engine but i really would like to massage this little 2hp into the max it could be. Can you guys tell me what recipe you recommend. I just got it and all i have done is ordered mikuni carb and i also reground the compression relief off the cam and this feels like a completely new engine . i will port in the next few days but i wanted yall expert input as to what extent i should. What should i time it at if i stick with 93 octane? should i shave head as well as deck block? is there any power to be gained my moving plug in head to center of bore ? Should I lap crank and flywheel to advance timing without a key? or should i make a custom bracket to allow coil rotation/timing adjustment. What timing do i want 28* ? Does anyone sell a billet flywheel for this? I could make but i would have to get it balanced and so it would be easier just to buy it. Thank you for all your input experience and ideas, the engine is so old and simple looking that its quite comical to see it hauling butt with an old fat guy on it (me 50y 240lbs)
 
I would say to follow the advice for turning a run-of-the-mill Briggs 5hp tiller engine into a mild speed engine, problem is the lack of hop-up parts for the 2hp engines, there just aren't any. I think you're wasting your money on 93 octane for such a low compression engine unless of course you are able to raise the C/R to 10:1 or such...

But yes, do everything you have listed to it and see what happens. Do a governor delete at the minimum.

:coffee:
 
I put a PZ19 carb and exhaust on this 99cc mini bike. You can find the carb on Amazon for around $8, I think. With a governor delete it ran pretty good but it did not have the torque that a stock Predator 212 has.
 

Attachments

  • mm80a.jpg
    mm80a.jpg
    78.7 KB · Views: 49
derf said:
I put a PZ19 carb and exhaust on this 99cc mini bike. You can find the carb on Amazon for around $8, I think. With a governor delete it ran pretty good but it did not have the torque that a stock Predator 212 has.
Click to expand...
Is less torque from a 99cc engine than a 212cc engine all that surprising?
 
I wouldn't waste the time on the 2HP engine when there are 5HP engines a dime a dozen right now - many of which are already built up.
Aftermarket parts are widely available for the 5HP flathead platform - not so much for the 2HP engines.
Before disconnecting that governor, you might want to program up a billet rod for your cnc machine. (Especially with that engine sitting between your legs.)
Forget about compression - you'll get none. Increasing compression ratio with a flathead hurts the power due to shrouding the valves and killing the airflow.
All the same principles apply to building up your little flathead as to its big brother. There are plenty of threads on here regarding "hop-ups" to the flathead.

Whether you stick with the 2HP engine you've got, or pick up a 5HP engine on the cheap - have fun with your project. Just be safe.


-----
🏁Thanks and God bless,
Brian Carlson
Carlson Racing Engines
Vector Cutz
www.CarlsonMotorsports.com
Carlson Motorsports on Facebook
www.youtube.com
36 years of service to the karting industry ~ 1Cor 9:24
Linden, IN
765-339-4407
bcarlson@CarlsonMotorsports.com
 
You must log in or register to reply here.
Back
Top