My 95lb 9yr old lovers her Viper 70 and for the past year we have had no mechanical problems at all. Unfortunately, it doesn't do well in the soft sand. I know there are many aftermarket parts out there to boast the power a bit but i'm not sure it is worth it to drop $600+ on a big bore kit, exhaust, etc... will bumping this engine up to 90cc solve the problems in the sand?

 

For about $600, I'd start out with a pipe, carb, high compresion head and clutch kit. Then get some port work down the road when the top-end needs freshened.

 

I'd sell it and buy her a 90cc quality machine kymco , honda, polaris, artic cat etc..
In stead of investing any more.
The other will give you all that you need with no mods.

 

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simtis: Welcome to this forum.


If you drive on trails that have strict age to engine size CC laws, you may NOT be able to legally upgrade to a pure stock 90cc mini. Thus, your best option is to upgrade the 70 CC - with the mods Raptorlegs mentioned.

Depending upon the "soft sand" depth and looseness, you "may" have to upgrade a pure stock 90cc as well. Most pure stock 90CCs are made for "average" trails that include some sand, some gravel and minor hills. If your riding area is extreme soft sand with lots of hills (like extreme sand dunes), then upgrades to a pure stock 90 may be required as well.

Of the brands suggested, the artic cat will need its factory many restrictors removed, the Polaris has weak wiring / stator, the honda is a 4 stroke that involves shifting (but great for water / crud conditions) and the kymco has a reputation of a solid 2 stroke with disc brakes. If you are pleased with the E-Ton brand and are NOT restricted by local riding laws, upgrading to an E-Ton 90 (instead of beefing up your existing E-Ton 70) might be worth it in the long run. If it were me with no law restrictions, I'd probably upgrade to an E-Ton 90 (body sizing thing) and if more power is needed for soft sand as the rider gets physically bigger, upgrade the pipe, air filter and install CVT upgrades. I'd only upgrade these areas "if needed" in the loose sand with larger body size (during a 3 year period).

Hope this helps as well....

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A modded 70cc will run circles around a stock 90. And I've yet to see a stock 90 do well in sand either. Don't waste your money.

 

You are right Raptorlegs.

In thinking of the bigger picture:

- What's the age to riding CC restrictions in the young rider's area? If public trails, gotta stick within the law's of the trail.

- What's the current physical body size? If a large kid, like my son, then his knees could be kissing his chin - on a 70cc mini.

These things have to be taken into account as well.

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Unfortunately the stroke is longer on a 90 than on a 50 /70 so its not an easy upgrade to make it a 90 unless you want to swap the crank as well.It's probably much cheaper to just mod the 70 unless you can find a 90cc engine and mod it instead[img]i/expressions/face-icon-small-happy.gif[/img] .........Spike the 70 and 90 are the same size,just smaller tires and wheels on the 70.

 

onreserve I'd put the Viper up against any of the"quality" machines you listed.

 

Appreciate everyone's informative feedback. It is becoming clear that there in no easy solution for now. Until I can get her onto a full size quad (250cc) she will probably have a hard time in the soft stuff. She is 56" tall and 95lbs so physically she fits pretty well on a Honda 250 but she is not mature enough or strong enough to handle a 250 yet, plus she is not 16.

 

Ohhhhh....If you own am impact wrench and ratchet set, it's fairly easy. Only hard part is letting go of the $$$. But trust me, it's kept me from pushing my kids up every dune we come accross. Now, she can pretty much climb anything I would ever want a 7 year old on.