Hey all,
I bought my grandson a 02 scrambler 90 so he could ride with me, he's 11 but is 5'2" and about 105lbs.
I should step him up to a 125cc but he needs to do some learning first, so what I'm looking to do is wake this thing up. I have heard that the engine has a lot of restricted power, I have also read that they do something with the CDI to step down the power. Can anybody give me some pointers?? CDI? Pipe? Crab? K&N Filter? ect..
Thanks for any help.
null

 

Call Billy Holt at WRH. He can set you up with a rocket, if that's what you want.

 

The 02 Scrambler has a non- restrictive CDI. So this is fine. Changing the reeds and a smaller rear sprocket will increase the speed of this little machine. I would suspect a top end over haul is needed soon just to bring it up to spec before getting a exhaust, etc. You have to have all the basics correct before building a good strong machine. No other restrictors per say are installed on this unit. It is built restrictive all the way through. From the air going in to the exhaust going out. Design wise.

 

Great web site link. And thanks for the advice. This 90 only has 20 hrs total on it. I think the top end can wait a bit. I took my grandson out yesterday to some hard pack, he flew, the sand and his weight is what robbing the power from it. Good to know about the CDI. I think I do a few mods and pass it down to the who is 6 and start looking for a bigger 4 stroke for him.

Again thanks,
midnightblues

 

Boysen Reeds will help bottom and responsiveness, also keep using a high quality 2 stroke injector oil.

 

What do you think about getting rid of the air box and mounting a air filter right on the crab?? I know I'll have to re jet, but I will anyway when I change the pipe.
Thanks

 

I'm not really a fan of that particular mod. The stock carb is a bit finicky. But it will work better for you with the stock pipe. Meaning you should be able to get it jetted and have it maintain consistency of staying jetted properly.

 

I have the same 02 Scrambler with the same concerns. I bought the hentrick powerup kit c and a k/n on the carb and it has plenty of power. It took some rejetting to get the mix right but now it is smooth and fast. I have purchased the keihin 20mm carb, reed and intake kit but haven't installed it yet. I am hesitating for a couple of reasons... I am not sure I want to disconnect the oil injection and I don't know if the power gain is worth the work and $. Would appreciate someone sharing their experience with this carb set up.

 

Heck yeah the carb swap is worth it our bikes didnt really wake up till the WRH carb swap that 20 mm billy sells works very well youll run between a 100 to 112 mainjet and the bike starts sooo much easier. We now run a bigger carb on one of our stroker bikes so I'll try to post a 20mm WRH carb kit on the Swap/Garage sale They are one of the #1 mods for the 50/90cc 2 strokes as well as a good head and pipe really makes them FAST. IMO. FastD