Big Bore 170cc Kit

[Taught2BeCautious]

I wouldn't recommend that you do this, but a lot of people seem to be interested - so here is the link:
http://www.unlimited-power.net/Varadero_125-shop_list-13.html

They don't state exactly how many horsepowers you will end up with, but I remember someone on this forum from Ireland doing the upgrade a couple of years ago, and wasn't overly impressed with the results.

If you find yourself reaching for your wallet though, I suggest that you actually speak to the company first, to find out what else you need in order to get the most from the system - such as modifying the cylinder head, inlet and exhaust ports and valves, intake and air filter system, and of course, the exhaust.

As a modification of this kind will take the bike outside of the 'learner-legal' category, you will also have to shop around to find a company daft enough to insure you - after you pass your test

[black rider]

how daft would it be to go tuning a 125cc 4 stroke for all you might  gain in power its not worth the risk or expense   . there is nothing like a factory build engine for long life  . a  2 stroke 50cc scooter on the other hand would be a bit of fun to derestrict I hear  a 75cc  barrel and piston is only like ?30 . this day and age there is no point at all in messing with big bore kits just bide your time until your old enough test passed or what ever and buy a 170mph bike for  well under ?1000 if its speed you want . big speed has never been cheaper     something capable  of evading high speed pursuit from ground units at least no beating the eye in the sky though 

[mozza83]

I have a laugh to myself when I see a 125 with some kind of racing can on it. Even though my 125 had one on it when I bought it.

?100 for an extra .5 HP (if that) makes no sense when you can get a 100 HP bike for ?1000 easily enough.

[black rider]

 having a good dump and emptying your pockets of loose change would probably give as much of a power increase  . back in 1989  a friend of mine had a Honda h100s  I don't know what had been done to it the exaust had been cut  clean off near enough the front and re welded  . I never did get around to asking him what had been done to it but the thing was a absolute flier I had to ride hard  to keep on a Yamaha  rd125 ypvs and I rode the wheels off that thing  .  I suspect a crazy old mechanic dude who raced Yamaha tz350's had a hand in it . 

[Taught2BeCautious]

He probably cut the exhaust and removed the internal restrictor, which was about a 10" section of smaller diameter tubing welded inside - similar to what the Vara has.

This has the effect of allowing more of the burnt gasses to clear the cylinder, so the next charge will have a cooler, denser, more powerful air/fuel mix.

Back in the real world, you probably only have 10-12 bhp to work with at best, so spending a small fortune to gain a 10% power increase (if that were even possible) in nothing to shout about.