Help needed

i have a Gasgas 70 rookie for my daughter

it seems to have little low down power then bursts into song

it seems to have good compression but I was going to give it a top end refresh someone has told me the derbi senda 70 has the same piston .

can anyone confirm this please

I have experience with a GG TXT Cadet/Rookie having maintained one for my son for a few years. I too tried to improve the power delivery; custom flywheel, lower gearing, a new OEM piston and cylinder kit (I think it was the last one I could find in America [and Jim Snell had it]), etc. In the end I came to the realization that it's a screaming scooter motor in a trials frame; there's just no low-down power to be had.

At the time of my realization my 13 year old son was a whisker thickness shy of 6 feet tall, so we got him a used TXT 280 PRO, and that's brilliant (after reducing the compression by way of a head spacer and adding a flywheel weight).

Still, the Rookie was great to teach basic trials skills and use of the clutch and gearbox, but Evan wasn't lofting the front wheel for sustained wheelies or doing big-power operations. So the trick to the bike might be to use it within its limitations and then move on to a more capable bike.

Dale

 

Edited October 30, 20196 yr by d2w

Totally agree with d2w, I had 2 of these. Still have the 1. Its very under powered  and runs out of steam up hills or comes alive higher up the revs and ends up with front wheel up in the air. Not ideal for beginners. Its just the way they are. Perfect for aggresive, fearless, youngsters. I think this is why the Beta 80 is a better bike and more expensive. 

Yup...my son had one. Difficult bike for beginners.

My other son had a 125 Sherco that, surprisingly, wasn't much different.

Have to keep it in low gear to keep revs up.

I think 4-strokes would be best for kids because of the power delivery, but I guess the makers try to keep the prices accessible and 4T wouldn't help that.

But I bet the chassis from that GG 70 with a little Honda XR 80 or 100 would be a great bike.

In general, a compression test would tell you if you need top end freshening, not power delivery.