First club race of 2020 Rok VLR video

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John Kwong
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First club race of 2020 Rok VLR video

Post by John Kwong »

Here is the ROK VLR Club #1 race Final:

https://www.youtube.com/watch?v=AeEh_OB9mxQ

John K
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evannadeau
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Re: First club race of 2020 Rok VLR video

Post by evannadeau »

Hi John. I tried to watch your video, but it is marked private.
VLR #42

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John Kwong
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Re: First club race of 2020 Rok VLR video

Post by John Kwong »

Video should work now.

John K
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Re: First club race of 2020 Rok VLR video

Post by John Kwong »

My experience for the first race event and leading up to it. My hope is that this will help anyone looking at this class and the guys that are already racing it.

The Build:
Motor package installation was pretty straight forward. Motor mount bolt pattern is the same as Rotax. After fitting the seat struts, I decided to use a 10mm motor mount spacer to better clear the right seat strut without having to bend it. The wiring harness was very easy with only a big plug and a little plug to deal with as well as the battery box that fits easily on the left side frame rail. I had a foam air filter with rubber boot left over from another kart that I fitted to the air box as it isn't worth the very small air flow difference to go without one.
Set-Up
Jimmy suggested 10/82 gearing and that has worked pretty good so far with the motor twisting to about 15,200 rpm. Carb settings have been about 1 1/8 on the High speed and about 1 to 1 1/8 on the Low speed needle. I am using a right angle exhaust temp sensor as the straight mychron one I had did not seem to reach into the exhaust port enough and was giving me odd readings. Temp readings were about 1120 at the highest readings at the end of the longest straights. Tire pressures we used were 12 front and 14 rear. 2.5 spacers on each side on the front with 75mm hubs and 54.75" width at the rear with 95mm hubs.
Driving
Driving this motor requires a very similar style to the Briggs in that getting loose or off the throttle too much tends to lose momentum and engine response. The benefit of it being a 2 stroke motor negates this feeling initially until someone who doesn't back out of the throttle as much or carries more speed is able to make up time on you. Here are my comments for doing a Counter-Clockwise lap at Strathmore Motorsports Park with a Vortex VLR:
Turn 1: Flat out with mid corner apex. Using curb is risky and can bounce you out of track on exit.
Turn 2: Center right entry but not as deep braking as before track renovations. Do not overdrive or be too aggressive on entry as the apex is easily missed. Smooth driving rewards a good exit. Use all of the new asphalt and move to center left of track to set-up for Turn 3.
Turn 3: This curb can be used if the entry is done right and the kart is jacking properly but not entirely necessary to do. Exit to far left and follow to infield hairpin.
Turn 4: Infield hairpin is now less extreme and harder to see with the high grass this spring. Once you turn toward the apex the track starts going uphill and will create grip on the exit of the first part of the turn which you can start accelerating from and continue to use full throttle all the way through the Turn 5/6 chicane. Upon exiting this you will proceed to a center right position to set-up for the uphill Turn 7. This corner is now curb friendly and doesn't upset the kart much if you use it. The new exit curb is useful but using too much can be a little slippery. For Turn 8, do not use the curb as it will bounce you out and cause a loss of momentum. The exit curbing here is mostly to save you from a huge mistake and is not faster to use on a regular basis. Once exiting Turn 8 proceed to the left side of the track to set-up for Turn 9. This once doesn't require a huge amount of braking because the exit of the corner opens up and the exit curbing is mostly there to save your frame and is not needed to be used as the regular line. For the entry to Turn 10, I prefer to apex the right curb and enter about mid track but brake early so I can maintain a tighter exit. Carrying more speed and driving really wide on the exit of this corner is only making your drive a further distance which you don't have the horsepower to overcome. Proceeding down the back straight, I apex the left curb and just use a little bit of center right of the track to set-up for the set of S curves. The first left curbat Turn 11 is to be used a lot or not at all. Halfway between just upsets the kart. As you then go up a small hill to Turn 12 you will need to turn early enough to not overshoot the corner as just after the apex is the highest point and the kart gets light here. A mixture of throttle and brake is used to finesse the kart through these curves and upon exit of Turn 13 onto the straight, you can use this exit curb to advantage.
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dvelpel
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Re: First club race of 2020 Rok VLR video

Post by dvelpel »

Hey John,

Great write up and hopefully everyone can benefit from this so we can have some good close racing!

I was running 10/85 so was going the other way, also was having issues with the carb as it wouldnt idling and the low end would just sputter but once I got going it felt really good. Definitely need to look at a elbow pad or something as mine is all bruised. As this is a new class for myself I did find it extremely physically tiring compared to Briggs and basically ran out of energy for the last half, might just be because its the first race or might be chassis setup.

But overall it was great fun and happy I joined the class, great step up from Briggs. may need to look at adding some lead as I was 362lbs on the scales for seniors

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Re: First club race of 2020 Rok VLR video

Post by evannadeau »

Thanks John, and great video. I certainly like that play by play. Can you do a voice-over, so I can play it in my helmet like a rally co-driver? ;)

Although not getting into VLR yet, only doing some rent-a-kart, I'll take those tips to the Briggs class. Thanks.
VLR #42

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Re: First club race of 2020 Rok VLR video

Post by John Kwong »

Dan,

The lack of idling could be a couple things. I find the non-rotax engines typically need to be at a higher rpm to idle successfully. Not sure if this is because they don't have a balance shaft like the Rotax. Also, the carb might have some debris in the idle circuit which you can check by taking the plastic top where the fuel line goes in. I think there is a circular screen in there.

What RPM were you getting with 10/85 gearing?

Yes, you may have seen my elbow pad which doesn't look great but no elbow sore spot after race day.

The OTK karts handle great but have heavy steering. Check to see if you can adjust the steering hub so that the wheel is closer to you. If it is already at that setting, make a spacer out of nylon cutting board. Your upper back should always be against the back of the seat even when turning the wheel. This will let your arms do the work and keep the weight balance the same in the kart.

John K
John Kwong___CIR Realty___403-714-5583
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dvelpel
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Re: First club race of 2020 Rok VLR video

Post by dvelpel »

Hey John,

10/85
MAX RPM=15262, MAX SPEED=92, MAX TEMP 966

From what I recall I was getting around 14600 when I had a 83 on which is the reason I started going up gear sizes. I'll have to pick up a 82 and give it a shot. I did take a look at the steering hub is at the closest position, rear axle is almost dead on to what you have your set to. neutral caster.

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