Going to race a Tony kart with a ROK shifter engine at Daytona, can anyone give recommendations for gears and jets?
19/20 if you find youre running in a draft, 18/20 if you aren’t. Start with a 165 main if using the rok shifter airbox and lean it out if needed (better to be safe than sorry)
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Awesome, thank you! Also, engine was built by a sprint track company, would I have to worry about the timing or anything?
It will work on the sprint setup but you won’t get any of that top end rev that you need at Daytona especially since the pipe isn’t helping you. May be worth trying to raise the port height and adjust the timing for Daytona. I dont know the specific values.
following this, as ive been interestted in getting into road racing with my rok shifter.
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Hey Jake I think you have me on FB, feel free to ping any questions. I ran my old rok shifter at summit point and mid Ohio. Stock configuration works but the pipe doesn’t really like the sustained rpm so you dont get any overrev like you would on a honda or kz. Mid Ohio specifically best you can do with the rok shifter is 2sec off pace. For summit point with the long straight you’ll most likely just be racing against the Hondas because its pretty fairly matched at that track, I imagine it’ll be the same for Daytona too.
How does it do with a KZ pipe on there? Assuming the engine is being run in a regular shifter class vs a RoK specific one.
You can run a stock rok shifter with an airbox and an RTZ pipe and gain most of the horsepower back but you’ll still be down compared to full kz
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The entire RTZ top end can just be bolted on to a rok shifter bottom end since the rok shifter bottom end is just the RVXX so it can handle the kz power. I had my rok shifter built in to a kz for Daytona last year but complications arose (unrelated to karting) and I wasn’t able to run it there. Then a good deal on a kk1 came up and I sold my rok stuff for that since im light and can use the weight break the kk1 offers.
Here is a video of the rok shifter with RTZ cylinder, head and pipe on a sprint track. It was spec’d for Daytona so mid-range power is non-existent.
I do! And we’ve talked on there before. I bought an airbox off you to run with my rok shifter actually.
Yeah I race in the NW with an actual RVXX cylinder and pipe on my Rok shifter bottom end. Ever since we switched to a TM flat top piston and lifted the cylinder a tad I’ve had no issues running with R1’s on sprint tracks. Haven’t faced an R2 yet. I did crack the TM piston and seize it once it burned a hole, but it was on about 6hrs or so if I recall.
Reviving this thread cause I’ll be doing a road race at Talladega Gran Prix. I’ll be taking my Rok shifter down there; switching to the KZ pipe is the most simple way to squeeze more horsepower from my engine? Having my engine rebuilt this month, so if I really need to switch to the RTZ top end, I will. Just don’t want to kill my wallet for the 2 total road races I’m probably going to ever do.
Should I run the KZ airbox? And any messing around with the pilot jets or just the main one?
I’ve heard the KZ pipe is the biggest difference, but cannot say from experience. As far as road race jetting I have no idea. I’d guess you could add some base gasket to raise up the cylinder and run the KZ pipe and get pretty good power, the lower compression shouldn’t be too big a deal especially on the big end.
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Ok, I ran my Rok Shifter for the first time at Summit Point AKRA race last weekend. Saturday, stock pipe/airbox, etc. got a screaming start and came around first lap in 2nd with all the KZs. Then I was hanging on for dear life and the Rok would not overrev as they were drafting past me and I faded. Kept fading and I ended up 10th as I ran out of fuel heading towards the flag. I am ordering the bigger tank for my OTK Redspeed to compensate for this. I read on the forums about using a KZ pipe on the Rok. Out of luck, another competitor approached me before the beginning of my TaG race and said he had a KZ pipe that I could try.
Wow, what a difference, it did allow me to overrev like my old Mod Honda would do in the draft back in the day, and I could hang a bit better but still down on power. It was a normal sunny day on Sunday and I used the stock pilot jet, jetted down to a 158 main jet, stock Rok airbox, and the KZ pipe. I was able to hang a little bit better and ended up in pack for 6,7,8th place. I was very happy with the KZ pipe, and instead of borrowing it to try, I bought it. Exhaust temps in the 1250s and the pipe silencer end looked like a perfect burn. I also topped of the tank to the very top and did not run out of fuel and came across 7th at the line and split the to KZs I was running with.
The next step for me would be the Cylinder upgrade that FastTech is selling, however, I am trying to decide if I want to jump both feet into the KZ world, I really bought this Rok with the hope that AKRA/Woodbridge Kart Club will allow it to run combined with Stock Honda next year with a weight penalty to keep parity among both engines. It didn’t make sense for me to buy a Honda since there are some obsolete parts that Honda no longer makes.
Hope this helps, the KZ pipe did exactly what the forums said and allowed the overrev that I was looking for.
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Ugh, I called Van Gilder about a month ago and he told me that I have to run the Rok pipe. I wish I had read this sooner and decided to pack a KZ pipe in the box to ship with my kart anyway. Hopefully I can get my hands on one at NOLA on Thursday or Friday before heading up to Talladega.
Appreciate the insight on everything! Super helpful and I’m feeling a little better about preparation.
In the absence of enough entries to justify a Rok Shifter class, that’s a slightly frustrating ruling. Will this be your first road race?
Depends if we count Canaan, NH as a road race. If not, then yes, it’ll be my first!
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