Author Topic: 70cc big bore kit results....  (Read 1379 times)

motoxman36

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70cc big bore kit results....
« on: March 01, 2018, 11:09:26 PM »
Hi all,

I recently, as of yesterday, had a local scooter shop do some work on my Agility 50. They put a 70cc BBK in, as well as do the usual fixes to the carb and rollers, etc. However, I've noticed now that the scooter doesn't ever do a a hair over 30mph... I was actually getting more top speed BEFORE the 70cc kit... Any ideas why? It was a $400 job, and man this scooter does NOT feel $400 faster... It's DEFINITELY got more torque off the line, but beyond that, it seems like it's struggling to get top speed.

Any advice would be great!

ps. I know derestricting the CDI is what most people recommend, so if anyone has any suggestions to a specific CDI I could buy myself and install, that'd be great!


Thanks in advance!  8) 8)

JJJoseph

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Re: 70cc big bore kit results....
« Reply #1 on: March 02, 2018, 03:47:17 AM »
the scooter doesn't ever do a a hair over 30mph . . . if anyone has any suggestions to a specific CDI I could buy myself and install, that'd be great!

The Kymco CDI is like a straight-jacket.  No matter what you do to the scooter, you'll stay at 30mph.  It only takes a few minutes to swap the CDI. Here's some samples from my parts bin, the yellow ATV one with the transparent case is the best. Adds about 1000rpm, idles nicely, and timing is adjustable. Don't know what make or model it is, but they're easy to find on eBay, about $15. The orange one is too hard to start, the orange Scrappydog is OK but rough idle, the Scooter Assassins one with the logo has a terrible idle but revs OK, the home-made Kymco with the saw-cut is the cheapest (free), adds about 500rpm. Any replacement CDI must be a DC version (not an AC).  AC CDIs are easy to recognize, they're  noticeably smaller than the stock CDI.

If you swap the gear set, you can get some extra speed, maybe another 10%.  Every little bit counts.
« Last Edit: March 02, 2018, 03:53:33 AM by JJJoseph »

blue

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Re: 70cc big bore kit results....
« Reply #2 on: April 04, 2018, 12:41:10 AM »
I could of got it going 45 to 50 with out bbk.

Tromper

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Re: 70cc big bore kit results....
« Reply #3 on: April 04, 2018, 04:19:59 AM »
I know a couple folks around here who did BBK's & the consensus is that it doesn't do much for top speed, as blue notes you can increase that without the kit, but it does add torque.
In hilly Seattle that makes a huge difference since it's a serious improvement in hill climbing.
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blue

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Re: 70cc big bore kit results....
« Reply #4 on: April 04, 2018, 05:25:01 PM »
For the hills you to change out main spring in the clutch.And did you up grade the verator.
« Last Edit: April 04, 2018, 05:27:58 PM by blue »

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