In the previous post where I discussed my eldest returning to karting, I mentioned that we had now bought a kart for him to use. This weekend just gone we attended the Open Test Session at Rye House. The goal of the day was to test the kart and make sure everything works as it should and give the kid some bum in seat time which is important at the moment.
The session was a 3 hour session, and there were two groups using the track. The cadets, and the seniors/rotax group. As a result, we were on a 15 mins on, 15 mins off timing. This gave us a chance to discuss things between sessions, make sure all is happy and then carry on. These felt like very fast 15 mins, but they were 15 mins non the less!
Before we headed to the track, on the Saturday night, a good friend went over the kart with me, just to identify any potential failures, make sure it was set up correctly and just ensure we were looking to have a good day. I cannot thank them enough for this, karts are new to me, what you can and cannot do, what changing a part does (i.e. does it affect handling) etc. Needless to say, almost everything was taken off, checked, and replaced/put back on/tweaked.
First thing we did was change the pedals. When we got the kart, the pedals were on the shortest mounting point (inside the end of the chassis), this meant that the eldest’s knees were up around the steering wheel. We moved the pedals to the tallest setting (outside the end of the chassis) and this made all the difference. Eldest looked a lot more comfortable. Changing the pedal position meant putting in a new brake bar (connects the pedal to the servo), new backup cable and replacing the accelerator cable. The accelerator stops were tweaked for the new positioning and return spring added for safety.
Staying at the front, the wheels were removed and alignment checked which was all good. The floor was removed and a hole drilled below the steering column just to provide some clearance. The bush on the steering column is worn providing some play in the column itself so we will need to replace this.
The middle of the kart was fine (side pods, seat, etc), the fuel lines could probably do with a replacement as air does get in to them somewhere, fuel lines are cheap so we will get this done. We moved on to the rear. Problem was found almost straight away, the main sprocket was toast to say the least.
OK, so the sprocket is well and truly toast. When we bought the kart, we were given a handful of sprockets with it. The one fitted was a 78 tooth sprocket, we didn’t have an exact replacement so went with a 77 tooth sprocket. Whilst changing the sprocket, we checked the chain length against the spare one we were also given as part of the package. The chain had stretched by nearly almost a link and a half! Eeek. Chain replaced at the same time. New hubs are required where it looks like someone has overtightened the bolts. Other than the those, at the back seems OK. The brake was binding a little, but a quick linishing of the pads provided enough clearance. The engine was re-aligned, with the new chain length, and a new fuel filter thrown on as the one that was fitted looked like it was held together with bubble gum.
After the check over, we have formed a shopping list.
- Chain Lubricant (bought at the Rye House shop)
- Engine Oil
- Air Filter
- Plugs (don’t want one to ruin day)
- Fuel Filter(s)
- Fuel Lines
- Return springs for pedals
- Accelerator cable
- Rear Hubs
- Steering Bush
So, will shop around and get hold of these before the next test session. I will give the engine a service, purely because I don’t know when it was last done. Given the state of the sprocket, it’s probably well overdue.
On the Day
The day itself was a learning experience. When we arrived at Rye House, we were the second ones there so nice and early. I was able to get the kart out of the car and on to the trolley all by myself which was a big positive. After signing on at the office and being given our sticker, it was time to get ready. I got the Alfano installed and had a look at the routing one of the other parents had used for the RPM cable. I copied this and got everything working. Started the kart and could see the RPM being counted. Result. Checked the tyre pressures and set them at 20PSI to start the day with. One tyre was massively over inflated with a another being slightly over inflated and then the other two under inflated. Baseline set.
As we got ready for the first time on track, it was nice to find there were three of us in the cadet class and we were all helping each other with the little things like lifting the karts off/on the trolleys, and when one of the other parents needed cable ties and a spanner, I was more than happy to help.
Session one starts, and away the kid goes. The track layout is slightly different for the owner/driver use than the hire kart use. It took him a little while to get the hang of the new to him hairpin in the middle. Needless to say, he got there after following the other kids and watching their lines etc.
When the session ended, the eldest came back to the pits and explained he was struggling with oversteer, in particular when entering the corners. I had a quick Google, and it seems that in terms of setup, we could widen the rear track to help prevent this, however, it would change the handling characteristics. Another problem it could be, is down to him locking the brake on entry and just learning the kart. We agreed that he would give it another go and see how adapting his driving would help. I feel this was quite a good step for us both, it was tempting to go ‘oh god lets change this that n the other’, but changing the kart underneath him constantly would make it harder to learn.
Needless to say this seemed to do the trick. Second session, he was more comfortable with the kart, his driving was better and he made fewer mistakes. The rest of the day continued a bit like this, go out, do a session, come in, spray lube on the chain, maybe put fuel in and off he goes. Yes, he spun, yes he had a few adventures off track, yes he out braked himself a few times, but he was learning. There was one moment where he inspected the tyre wall on the exit of a corner but he carried on that session and took part in following sessions.
Lesson 1 on the day was around cadence braking, maybe I should have taught this earlier but he was talking about the rear wheels locking on the brakes. This I think was causing some of the spins on entry in to corners. We talked about coming off the brakes when they lock and applying them again.
Overall, on the day, the kart ran perfectly. I was very impressed. The eldest was learning, we kept half an eye on the Alfano, his fastest time of the day was a 49.73s but when looking at the data in more depth, he was fairly consistent in the low fifties. Brilliant. We will continue to work on his consistency with the racing line. From what I could gather, the two ‘quick kids’ that were there, one of which works with a Team, were running at about 43 seconds. I know full well there will be two elements to this. One will be driver skill, I know the eldest will get quicker with more bum in seat time. The second will be tuning of the kart. The two ‘quick kids’ were flying past him down the straights. I am sure we will get there but I am sure it will take a little time, with us both learning. Looking at the Alfano data, I can see the speeds were topping out at around 45mph down the main straight. The RPM looks odd though, sometimes it’s showing at <3k and others it’s going 5-6k. Not sure if I just need to wind more cable round the plug lead or if there is an issue.
I will get the shopping list bought and spend a little time giving the kart a bit of a refresh. I will check over the the gearing, I read on karting1.co.uk that cadets at Rye House should be on a 20:77 gearing set up to be quick. Hopefully the fuel system refresh and service will help the kart. I could do with checking out the RPM readings to work out if it’s the Alfano not getting a clear reading or if it’s the kart not revving high enough.
I will have a look at what a ‘good’ GX160 engine looks like (compression ratio, timing and gearing in particular) as well whilst I wait for the parts to arrive. I am keen to not adjust the handling too much (yes OK power changing is altering it) whilst he still learns how to drive the kart. I will try and do a blog post (with more pics) or a video showing the work we do to the kart and it’s refresh.