I recently picked up a 99cc Predator engine from Harbor Freight in anticipation of an upgrade to my 1950 Schwinn Panther, which currently is running a 50cc Hua Sheng mated to a Qmatic transmission. The anemic HS is a nice engine, starts well, runs smoothly and is simply not enough Hsp to suit my needs. I'm 200 pounds, have hills to climb and a dog in tow. And I don't want to pedal which is why I have a motor bike in the first place.
So, I'm preparing the engine now and will purchase pulley and belt next month as money permits. Always on a budget, I'm now making up a do it yourself throttle control and some changes to the stock air box. The air box is the subject of this thread.
A couple of years ago I did a similar modification to a 79cc Greyhound engine which has pretty much the same footprint as the 99 Predator. The air box is also by all appearances the same. I don't like plastic and it is really the only thing I don't like about the appearance of the engine. A big plastic box. Gotta go.
I've seen others here use some cool looking round air filters, one of them from a Whizzer. I made my own for that Greyhound out of a double size tuna fish can and loved how it looked. I felt so clever.
Until I rode the bike. These engines are wide, so anything sticking out more than the original air box is an issue, in my opinion, based on my own experience with my build. A different bike might not be a problem, but for mine it was. My leg kept running into the air cleaner I had made.
So I went back to the stock plastic box, still not liking it, but at least my leg wasn't running into it. Then I modified the cover with one I made from tin, which was the prototype for the one I made today for the Predator which is the subject of these photos. Form follows function... I wanted it to tuck in close to the engine and get a good gulp of air while protecting the engine... and it does.
If you look at the stock plastic cover you can see there is a lot of wasted space, it being larger than it needs to be. While it is big, there isn't all that much air intake as you will see in the photos. My modification uses the original air box and doesn't need to be removed from the engine while doing so.
There are two tabs, one above and one below which received bolts holding the plastic cover in place. I cut these off with a cutoff wheel on a Dremel type rotary tool. This cuts down the size of the needed cover quite a bit, as you can see.
(cont.)
SB
So, I'm preparing the engine now and will purchase pulley and belt next month as money permits. Always on a budget, I'm now making up a do it yourself throttle control and some changes to the stock air box. The air box is the subject of this thread.
A couple of years ago I did a similar modification to a 79cc Greyhound engine which has pretty much the same footprint as the 99 Predator. The air box is also by all appearances the same. I don't like plastic and it is really the only thing I don't like about the appearance of the engine. A big plastic box. Gotta go.
I've seen others here use some cool looking round air filters, one of them from a Whizzer. I made my own for that Greyhound out of a double size tuna fish can and loved how it looked. I felt so clever.
Until I rode the bike. These engines are wide, so anything sticking out more than the original air box is an issue, in my opinion, based on my own experience with my build. A different bike might not be a problem, but for mine it was. My leg kept running into the air cleaner I had made.
So I went back to the stock plastic box, still not liking it, but at least my leg wasn't running into it. Then I modified the cover with one I made from tin, which was the prototype for the one I made today for the Predator which is the subject of these photos. Form follows function... I wanted it to tuck in close to the engine and get a good gulp of air while protecting the engine... and it does.
If you look at the stock plastic cover you can see there is a lot of wasted space, it being larger than it needs to be. While it is big, there isn't all that much air intake as you will see in the photos. My modification uses the original air box and doesn't need to be removed from the engine while doing so.
There are two tabs, one above and one below which received bolts holding the plastic cover in place. I cut these off with a cutoff wheel on a Dremel type rotary tool. This cuts down the size of the needed cover quite a bit, as you can see.
(cont.)
SB
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