Hey guys, i'm new in the karting scene. Based on my own understanding, the ROK engines are cheaper in terms of maintenance while the MAX engines are more expensive. What i don't understand is why most karts i see are running on the more expensive MAX engine instead of the ROK? Is that because of power? In actual, how does this 2 engines compare to each other in terms of maintenance, power, durability, etc?

Hope to learn more....

I've raced both the Max Senior and the ROK.

I believe in Malaysia the engine cost is almost identical? Maybe a few hundred ringgit difference.

For maintenance cost there isn't much difference from my experience. You can run both engines a fairly long time before rebuilds. Both engines use a very similar clutch (if not the same?), Both are rev-limited to the same maximum revs, and both have a balancing shaft. I believe the starter used is the same. I don't see where the max would be much more expensive to maintain. I think durability is very similar considering many components are almost the same. You should be able to run a full year on both engines without a rebuild.

On-track performance is with the max marginally faster. At 5kg heavier minimum weight the Max is maybe 1 to 5 tenths faster than the ROK depending on the track and other variables. The ROK has a slightly smoother power delivery on low revs probably because of the 30mm carb comapred to the 34mm on the max, although acceleration performance overall is about the same. The ROK then loses out on top range because it lacks a powervalve.

In Malaysia you see mainly Max engines running because that is what you can race here. There is no ROK racing series at the moment..

Thanks for the superb info! really helped me understand more...at least now i know that the ROK does not have a power valve...most probably will go for the MAX engine. Thanks again!

on the SuperRok their a power valve.

you will have to go with Max in this region.

For my 2 cents worth and like Mikko - I drive both engines.

I do agree that the Max has a higher top end but quite equal on other areas. The ROK is also much easier to drive and this is due the smaller carby and I think this is better for new drivers....

In regards to cost - imho, I do think the ROK is cheaper simply because the engine has many similar components with the 100c water cooled engines. For one, the radiator on the max is much more expensive and we are talking abt >1000 compared to a ROK one which is a universal type.

HOWEVER, the biggest disappointment in a ROK ownership is there is no racing category for it at present.....

So in short, if you want to race - get the MAX.

hi

i am using Rok now at Premas Jaya Track, after i cannot find parts to rebuild my Biland engine.

was quite pleased with the engine performance until race day.
i was found wanting in the low end torque.
will it be because of smaller sprocket size as compared to the rest of the field?
my friend who also race at Premas with Max & shifter drove my kart for a couple of laps
commented that Rok has a powerful mid to top end, and indeed had to painfully wait
for the kart to move out of the corner slowly...

so i wonder if my jetting & sprocket is wrong somewhat.
perhaps, bro Jules & RocK can share your views on it..

many thanks in advance!

how about the difference between the junior and senior engines? i'm new and i've just driven a ROK for a couple of laps and like you guys said, it's easy to drive but somehow or rather i feel the top-end dissapointing...

what top rpm are u hitting? suggest increase ur rear sprocket by 2 teeth n try again....

btw our race experience with ROK n Max are they run a different weight category.....ROK carrying less so - as far as I recall.

What about the correct working temperature range for ROK and MAX?

hi

if i do recalled correctly, the top RPM was about 13200+
at Premas, no matter wat engine one runs, there will be
a need of minimum weight @ 160kg.

yes, i will be looking to try to increase in rear sprocket size
in my next practice soon.

wondering if a jetting of 162 is ok for the weather here..

cheers

If I remember correctly the jetting on the ROK should be a fair bit smaller than the Max.




MAX:
Minimum: 45
Optimum: 65
Maximum: 80
That's degrees Celsius for the water temperature.

Thanks Mikko. Jetting on ROK will be 2 size smaller?

I really can't remember for sure what jetting we ran with the ROK and I don't have my ROK notes.

Best to do a few plug checks before going leaner.

Jules do you remember what jetting you ran with the ROK compared to the Max?

Mikko,

I do remember it is smaller too but I cannot recall honestly. Can check over the weekend but 162 seem stuck in my head.

Btw, where's your jetting software? I know u have one for ROK too......so what's their standard say when compared to Max's 168?

Btw, I pull 13500-13600 consistently on my ROK......even when I did not rebuild for quite a while now.

Thanks to Mikko and Jules. Will try it out and share the result.