Best 4 stroke engine for second kart?

Hi, i currently own a rotax max pre evo intrepid kart that i rebuilt and got track ready last year. I dont have a massive urge to race atm just want to do test track days as the closest track to me about 1.2 hrs away. I live in Ireland and the rotax is a very popular engine. But i have a second intrepid chassis laying up in storage and id like to put a 4 stroke engine on it. Ive been trying to find the most popular engine used here in ireland but cant find any.

4 strokes whilst alot less intense and slower can provide a more fun experience, less maintenance and teach people technique and so on. I know pro karts were a thing back then as i owned one as my first kart when i was 12 or 13. I was thinking of putting a gx390 on the kart or is this too underpowered? Will i need to mod this engine for it to be of any use? Ive seen the new tillotson t4 chassis and engine on offer. This looks good but i dont need the whole package. Im sure i could purchase the engine itself but id like to know what guys in ireland are using for 4 stroke racing,

I have driven gx390 on tony kart frames. I am in favor of your plan.
Put a long lasting harder compound on it, sorta like a rental kart.
So. Much. Fun.
For so little money.
Top speed on straight was around 55-60ish. But, it drives nicely and without being overly gripped up, it’s the real deal. I think if you put it on too soft tires, it gets dumbed down a bit.

In Ireland (from there myself) I’d go with the Tillotson 225. The 390 is a big lump (I have a bunch of them) and you have the benefit of being able to race a 225 vs being stuck with the 390 as just a practice engine. The 390 is fine power wise to move a kart, the Tillotson is around the same power without the extra weight.

If you really want to go with the 390 platform, see if you can get a clone 460 which is basically a stroked 390 with a 94mm bore

Thanks, yea my thought was that the tillotson 225rs was designed to be a racing engine whilst these gx’s are commercial designed i think.

Is there much racing or classes in 4 strokes here in ireland or is it all rotax ? No wonder those 206’s in the states are so popular, you dont have to be lewis hamilton to win, or a huge bank account lol

I was gonna say the gx390 is a pretty big engine size wise. I kept banging my elbow since it was large.

I personally love the world formula. It’s growing and it has a decent amount of power. Top speed can reach over 60

I think they are saying the European tillotson outputs similar but is a race as opposed to industrial engine. So it’s lighter. That seems like a winner.

The tillotson in growing in Ireland. Otherwise not much four stroke. World Formula ran for a few years, esp up north but died out.

@AFallon can give you the low down on the 225

Yea i like the idea of what tillotson are trying to do keeping costs down, fair playing ground for all its just that if you want to race your tied to their chassis whereas the lo206 are just the engine and tires ?

Check out the Super 4 Series, Bilands/SwissAutos etc… not as cheap as any Honda stuff but a whole lot faster

Is there a super 4 series in Ireland?

It’s the Biland/SwissAuto series in Ireland i believe, can only run standard engines though

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Hemi Predator 212? As far as quality, price, and performance goes.

Buy a 460cc clone 10bolt case, put a good cam, carb, head work and run it on alcohol. You will be able to run away from the Rotax. Should be around $1000 to build.