Take me to engine School...

Mini Bike & Go-Kart Parts

#1
I'm about to do my first chopper build and I am all over the map as far as which engine to get. Honestly I'd really like electric start but the cost effectiveness of a Harbor Freight predator is tempting..
Maybe some good information will help me make a much more informed decision utilizing the forums experience..
First question the Harbor Freight predator some people say non hemi? I assume that the one for $99 is a non hemi and is there a way to get one in the hemi model or is that just another engine totally?
Second up is going straight to the wallet LOL the go Power sports tillotson hemi electric start? Is this going to get me some serious more bang for my buck over a Harbor Freight predator or just electric start?
Third would be middle of the road I guess the Duramax 212 7 horsepower? This has electric start and is about a medium price and it seems very readily available to be ordered through any home Depot Lowe's or wherever..??
All of this is going in my homemade chopper with 10 inch wheels and a torque converter.
Would pretty much any of these engines send me into the stratosphere? LOL
Is there something out there that I haven't mentioned?
I sure appreciate everybody's time and experience if you have something for me. I'm feeling a bit like a ship without a rudder at this point as far as the engines are concerned..
Again thank you for anybodys help...
 

SAS289

Active Member
#3
One of the things I though about when looking at the post was that I wasn't sure what you want to do. Do want to just buy an engine to bolt in and go or do you think you will ever modify any of the engines you may choose? You would be happy with any of the engines you mentioned bolt in and go.

Do you want the most powerful out of the box engine? That would be the Tillotson. And Davis already mentioned the best quality engine.

Chances are I will never buy another new engine for a mini bike. If I did I would try to find a 196 clone. But that's just me. Search the forum for info on the Predator. Should have plenty of info on those. I wouldn't want the Duramax.
 
#4
One of the things I though about when looking at the post was that I wasn't sure what you want to do. Do want to just buy an engine to bolt in and go or do you think you will ever modify any of the engines you may choose? You would be happy with any of the engines you mentioned bolt in and go.

Do you want the most powerful out of the box engine? That would be the Tillotson. And Davis already mentioned the best quality engine.

Chances are I will never buy another new engine for a mini bike. If I did I would try to find a 196 clone. But that's just me. Search the forum for info on the Predator. Should have plenty of info on those. I wouldn't want the Duramax.
Well for now I'm starting to question my chopper idea as it's getting closer and closer to snowmobile season and I'd like to spend some money that way. Which means my new engine idea may get put on hold with it... From the speed I'm getting out of the 190 Briggs & Stratton on my Bonanza I'm sure a $99 Harbor Freight hemi predator will be plenty...
Live and learn LOL...
When you asked if I'd like to modify it in the future LOL it was quite obvious that this forum doesn't know me very well LOL... And here's where my LOL comes from.. my 73 Duster I built...
IMG_20200728_163012.jpg
You could say modifying is in my blood a little bit...:)...
 

SAS289

Active Member
#5
Awesome on the Duster. Manual or automatic trans?

Yeah then you would want the GX200 or a Predator if you are going to modify for more power. The knowledge base is out there along with the parts needed. From what I understand (someone correct me if I'm wrong) if you want to build a very powerful Predator get the non hemi. Milder or staying near stock get the Hemi. Research that.
 

65ShelbyClone

Well-Known Member
#6
Predator shortblocks are all comparable. The non-hemi head has more build potential and is less difficult to get bigger flow numbers from. The hemi head also limits valvetrain options due to the shorter valves and integral rocker pedestals.
 
#7
Predator shortblocks are all comparable. The non-hemi head has more build potential and is less difficult to get bigger flow numbers from. The hemi head also limits valvetrain options due to the shorter valves and integral rocker pedestals.
The old style has a different size cam journal than a hemi and clone.
 
#8
Awesome on the Duster. Manual or automatic trans?

Yeah then you would want the GX200 or a Predator if you are going to modify for more power. The knowledge base is out there along with the parts needed. From what I understand (someone correct me if I'm wrong) if you want to build a very powerful Predator get the non hemi. Milder or staying near stock get the Hemi. Research that.
Real men have three pedals...lol...
 
#10
i prefer the hemi as it uses the same cam as most clones. Non hemi has different cam journal sizes. Hemi has a nice design flat top piston. I always replace flywheel and rod so the crank flywheel taper is not an issue for me. Hemi head has same max flow as rtc8 or 9 but with similar valve size and ported I get a bit better results with hemi. Pressure recovery is also better with the hemi head than the bathtub chamber. negatives are as discussed above the rocker pedestals will break with high spring pressures from dual springs and valve to piston clearance with larger valves need piston valve reliefs with long duration Cams or tight lsa. Hemi uses standard side cover gaskets.
 
#11
I gather the hemi predator is pretty much all name and no real benefit?..
The hemi has larger chamber head so even with the piston flush with the deck and a thin head gasket you don't have the compression as the clone style does. The hemi heads can worked,but are limited to total lift.
 
#12
Stock is 22 cc,s. It comes with a .045 head gasket if it's .020 in the hole you can run a .010 head gasket . What lift limit are you talking about?
 

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