My 2 cents.
I’ve tried many different engine combinations and I personally run a cr125 in ‘stock moto’ trim under a similar but newer chassis (Birel cry32). I absolutely love it but you said you are new to karting… I have seen many people jump into the deep end with a cr125 shifter and jump back out just as quick. It’s a great setup, reliable, fast, easy to work on and cheapish. BUT in my opinion for someone starting the cr80 is the way to go. You will have to remove the front brakes if you want to compete but you said you didn’t. Cr80’s are not nearly as brutal as the 125’s and are much cheaper prob 1/2 the cost. You will learn to drive and have much more fun out of the gate. They are also a good engine to learn to do rebuilds on. Being able to rebuild your engines is a huge $$ saver if you plan on spending anytime in the sport. Then after a couple of years if you want more speed you can always upgrade.
Frame spacing is NOT the same
it will be:
30×90 or 30×92 or 32×90 or 32×92
Most Birels are 32×92 but you neeeed to measure. Look on Youtube.
In my opinion (its just my personal thoughts ok no one get pissed) the Tag motors are much too $$ and finiky for someone new. They are not nearly as do-it -yourself look up a rebuild cost and then imagine paying that every year. However they do make some of the best racing out there too.
The KT: great lil engine but you will have a very hard time selling it once your done.
Whatever you do make sure you get up to speed on 2t basics they are crucial in karting and all of the engines your looking at will need tuning day to day.
Also whatever you do make a yearly budget! You will need to replace things every winter. A lot of people get frustrated because they think pistons, gaskets, bearings, chains, clips, cables, fuel line, brake pads all last forever. They don’t they are consumables and it only takes $4-500 dollars at the end of the season to freshen up your chassis yourself.
Let me know if you get a cr80 or cr125 I have a wealth of knowledge and yes there is very little info out there for the first timer.
Hope you catch the bug!
" Turd Ferguson is real and he will pass your a** "