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,
Thanks
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 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.
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 ?
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.
Ronald out of curiosity can you link to a couple of race results that had the 460 class running? Having a debate with someone that is 100% convinced a four stroke cannot get near a two stroke.
I vote for the Tillotson, especially with the updated configuration (higher rev limit, easier starting). Very fun and fast enough that you have to drive the kart, not just hold it flat everywhere.
This has definitely not my experience on sprint tracks. Even when that is the case (eg rock island) there’s a definite finesse required in your steering inputs required to be fast.
When I did the rock last year in a 206, it was definitely easier to drive and less challenging in that aspect. On the other hand I found it harder to be competitive in the 206 class compared to when I did masters shifter in 2011 ish. Then again I put the shifter in the barriers, unlike the 206
I’m not saying it doesn’t take talent to drive a 206 or even a rental kart fast. I’m saying that compared to a 206, the tilly requires more braking and throttle control, and carries a higher speed through faster sections, which is more fun for me.
I can do one better, we usually run with Yamaha legacy pipe now. The 420cc karts are at minimum 460lbs about 100lbs over Yamaha. This video is a few years back running against the always fast Andy Kutscher and Chris Kutscher.
These are small camshaft, stock ports, stock carb slightly bored, stock piston, stock flywheel and on 91 octane… 420cc 7 bolt engines. A good 460cc makes upwards of 50hp on Alcohol, these only make about 22hp.
