Question for 79cc Predator owners

Please point me in the right direction. I will do the head but first I have to try gearing cause I wonder if thats whats kinda holding my speed down.
My gearing is 10 tooth clutch and 44 wheel sprocket on a 26 inch rim with no room to put a cvt on it cause its a trike so I just ordered a 41 tooth to try but not expecting any improvements.
What size motor are you using...........and........... is it a "live" axle w/2wd
 
Its a gas bike predator 79 and only 1 wheel drive or 1 wheel drives when you pedal and one wheel has sprocket to motor
 
https://electricscooterparts.com/motor-jackshaft-wheel-gear-ratio.html This is the easiest chrat to use. If you do not have a jackshaft, simply insert 1 and 1. Your ratio is 4.4 :1 and it's a wonder it doesn't stall your engine. If it could pull it, you'd be doing 64mph! My ratio is 9.4:1 and I am having a hard time climbing hills my first bike (15:1 ratio) does easily.

A smaller sprocket will make it go faster if you have 25 HP to pull it. LOL If you still have the governor you're really limited. The only logical fix would be to design and install a jack shaft so you can further reduce your overall gear ratio. Idealy a live axle ( go kart) would be best for mounting the big sprocket and a disc brake rotor, but that turns into some big bucks real fast. A faster less expensive solution would be ..........replace the 44T with something real big.

Amazon has 8oT sprockets that would need to be drilled for a rag joint. I hate those. Consider finding a front wheel that has a flange for disc brakes and use that instead. Anyway, an 80T sproket will only give you a 8:1 ratio with a top speed of 35mph @ 3600 rpm. This is 1.5 points lower than mine and mine is NOT acceptable. I'm afraid Pete, you are going to have to do a jackshaft. Maybe we should start a new thread so others in the future can follow how you resolve this issue more easily.
 
https://electricscooterparts.com/motor-jackshaft-wheel-gear-ratio.html This is the easiest chrat to use. If you do not have a jackshaft, simply insert 1 and 1. Your ratio is 4.4 :1 and it's a wonder it doesn't stall your engine. If it could pull it, you'd be doing 64mph! My ratio is 9.4:1 and I am having a hard time climbing hills my first bike (15:1 ratio) does easily.

A smaller sprocket will make it go faster if you have 25 HP to pull it. LOL If you still have the governor you're really limited. The only logical fix would be to design and install a jack shaft so you can further reduce your overall gear ratio. Idealy a live axle ( go kart) would be best for mounting the big sprocket and a disc brake rotor, but that turns into some big bucks real fast. A faster less expensive solution would be ..........replace the 44T with something real big.

Amazon has 8oT sprockets that would need to be drilled for a rag joint. I hate those. Consider finding a front wheel that has a flange for disc brakes and us that instead. Anyway, an 80T sproket will only give you a 8:1 ratio with a top speed of 35mph @ 3600 rpm. This is 1.5 points lower than mine and mine is NOT acceptable. I'm afraid Pete, you are going to have to do a jackshaft. Maybe we should start a new thread so others in the future can follow how you resolve this issue more easily.
Never has it even came close to stalling the 79 but I have always pedaled to get it rolling even on the 212 powered trike. New thread would be great if I get to the point of adding jackshaft that would have to have all sprockets on one side and man an 80 tooth sprocket would look as big as the 26 inch rim.
 
A round file might work well on the opening behind the gasket , but you will need a bur with a rounded end to work in the bowl and the valve guide area. I have ported lots of race car heads and speak from experience. Burs come with different degrees of agressiveness (for the lack of a better word) and less would be better. To keep fine burs from plugging up with aluminum I sprayed mine with WD-40.
I never did any car heads, just bike and Honda GX and clone heads.
 
Who sells head gaskets for the 79cc Predator?? Harbor freight does not even list it. Full sets are listed on Amazon and E-bay but I only want one gasket. 212 gaskkets are everywhere. It's like no one likes their little brother.

Have you ever reused the original? I realize it's not a good practice.
 
Who sells head gaskets for the 79cc Predator?? Harbor freight does not even list it. Full sets are listed on Amazon and E-bay but I only want one gasket. 212 gaskkets are everywhere. It's like no one likes their little brother.

Have you ever reused the original? I realize it's not a good practice.
I've reused an original on a 196. Still not the best. If you want to do a little DIY you can take an aluminum can amd cut and use it for a head gasket. It works and boosts compression a bit.
 
AGK needs to change their name Pete. There's nothing afordable about that place.

If I was going to make a gasket I would start with a sheet of copper instead of a tin can. I can't remeber the last time I saw an aluminum can. Making a punch for the headbolt holes would be a challenge. I've got a sheet of copper, just need to check the thickness. I wonder what the stock gasket measures? Does anyone have one they could measure for me?

I forgot about Copper Coat that I also used back in the day. I like this idea the best. Thanks CL
 
Back
Top