Apex/eton/predator engines? READ! DONT OVERLOOK!
 

So it’s no myster the DS models are disappointing weak. My little boy races one and I have done literally everything I can to it performance wise and it’s just not cutting it anymore. We are riding on more professional harder tracks now and some of the track sections drop way down and are nearly vertical coming out of the gully and his bake is barely making it out. It’s not safe. The apex drr swap is the popular go to engine swap of course. They are very slim pickins around where I am. I found an eton viper 90 with the hetrick power up kit already on it and I’m going to buy it to do the swap. They appear to pretty much be the same engine as the Drr. Is that true? I don’t want to do this swap if I’ll regret it and then have to find an actual apex motor after the fact. Am I wrong to assume they are pretty much the same platform. For that matter, what’s up with the predator 90? Is it also similar? I know responses on these forums are few and far between but maybe, juuuust maybe someone with chime in with a response.

A little less vague about what engine you are on about would help. I assume it is the Minareli 2 stroke 90. If so, Apache seem to be continuing to develop it and now have a water cooled "racing" version. No idea how good it is. I have a feeling there are long and short belt case versions of that engine, so you would need to get the same version for your bike.

the bike has the factory can am 90 4 stroke in it. I believe all those 2t engines are the same size/dimensions. Just making sure there isn’t a major difference I’m missing here.

As several different Chinese/Taiwanese companies make them, there is no way to tell, until you try to swap parts, unless you can find out if Can Am uses the same engine supplier as Polaris. I worked on a GS Moon "buggy" a while back and although it used a GY6 engine, GS Moon had altered stud spacing on the cylinder and head, so standard GY6 head gaskets were wrong.