Practice 7: Engine run-in and new fastest lap (not at the same time, of course…)

Today was our eagerly awaited practice day at Clay: having weighted the kart at Junior’s race weight and added the black restrictor (which is actually silver but, hey – it was a 99p eBay purchase and I took a punt, then subsequently discovered it wasn’t MSA legal having lost it’s anodised colouring!), I was really keen to see how Junior managed having picked up some good pace when unweighted last time. I awoke early as I seem to on every kart day – 4:55am this time, brain fully switched on running over the things I needed to remember to take and then all of the things to remember when we got to the track. Up at 6:10, out the door by 7:45 (just in case we hit Glastonbury traffic) and at the track at 9:15 – in plenty of time to get things sorted 🙂

Before we could really get going, our first business was to run-in the engine. This was our first session as a licensed driver 🙂 but Junior was driving up to 8,000rpm (or dangerously slow as it seemed) and there were a couple of close calls in our ten minutes on track. Afterwards one of the stewards suggested we continue running-in the engine with the cadets, which I was more than happy to do. This worked in the second session,when he moved up to 11,000rpm (and I bravely ignored a broken toe to resume bump starting duties ;)), but not in the third session where we were getting up to 15,000rpm and he got told off for racing cadets (and breaking my 40s lap rule!). Our job was done at that point though and, although he was still on a ‘not above 15k’ brief when back out with the adults, we could focus on the more intriguing part of the day.

It didn’t start too well – for the first time in our ownership the kart didn’t start and I was shattered, having ran myself into the ground well past The Kink! I am not sure Junior fully knows what he needs to when we are starting although, if I am honest, I probably didn’t fully understand either. It had just worked nicely previously. With some tips from friendly Dads (don’t pump the pedal, wait for the engine to spark then slowly and gradually accelerate), we got out again for three laps before the end of the session but, most importantly, it started fine.

After that things went just about as well as we could have hoped – the kart ran, we had no mechanical problems *at all* 🙂 (although Junior did spin into the tyres exiting the Top Bend), he was happy with the kart and preferred the handling with the extra weight on board (the back end seemed much less inclined to hop out as he accelerated out of the corner) and he knocked 0.7s off his previous best and recorded a 36.21. He was a little disappointed not to break the 36.0s mark although my biggest concern was the kart’s weight – Junior stood no chance of lifting the kart off the floor and I was reliant upon friendly faces to help me get the kart back onto the trolley. I don’t really want to keep putting on others so I might need to look at the self-loading trolley options. Chances are though, he’ll start growing by the time I finally get something sorted! All-in-all, it was a really good day; I think Junior is quick enough to race now (without being lapped!) although we have a lot on next month and I have promised him we’ll go to Dunkeswell for a practice day. August’s race meeting at Clay is the target 🙂

Cost of day: £12 petrol, £10 petrol for 7l super unleaded for the kart (session was free as we had a credit note after our accident).

Purchases since my last post: used set of slicks from the forums: £30

Total spent so far: £2,977

Farewell first set of nearly-new slicks!

They have been on the kart since we bought it and subsequently done 408 laps (or 241 miles!) but the time has come to bid farewell to our first set of nearly new slicks. Ironically Junior set his PB around Clay in his final session using them but there is no time for sentiment 😉 I have replaced them with another set of nearly new slicks that I bought for £30 from one of the forums 🙂 Removing the tyres from their rims was a smoother process than putting the new ones on – especially the rears. I think I could claim credit for maybe 1.75 of the 4 tyres so definitely more practice required. Not sure my office fingers are up to the job!

Whilst I was doing ‘kart stuff’, I completed the addition of the weight to the seat so we are almost good to go on Saturday (I have some good friends offering to help me with the push starting if the toe is problematic). I am really looking forward to seeing how Junior fares in the kart at his racing weight. Not so much looking forward to lifting the kart onto the trolley with him – he really struggled before we added 7kg…

Warning: motorsports can be dangerous!

Sorry for not having posted recently – as you’ll soon see things have ‘interesting’ of late :S I’d been spending quite a bit of time on the kart: I needed to put the engine back on following it’s rebuild and, whilst the engine was off, I had wanted to give the back end a good clean but had trouble removing the sprocket carrier so I was keen to put that right.

I spent three successive evenings working on the kart last week (when it comes to kart maintenance one thing invariably leads to another), firstly tackling the sprocket carrier: it was a little awkward as the sprocket protector was still in place on the brake side of the carrier but tap by tap, I managed to knock it with a hammer (lubing, hitting each arm of the sprocket carrier in turn and repeating until free – all whilst I had a pair of screwdrivers carefully tapped into the slots on the carrier to help free it from the axle. I got there in the end!

Whilst cleaning the back end, I noticed that the chassis was running at it’s lowest setting:

Tonykart chassis height

This is how you would set up a kart in hot weather, where you had too much rear end grip (you would typically raise the axle in the wet when you want to raise the centre of gravity) but this was not how I wanted the kart set up whilst Junior is still learning to drive so I removed the axle and set it to the standard (middle) height. And of course, I took the opportunity to clean the chassis around the bearings whilst I had the chance 😉

I then decided to adjust the seat as my measurements were some way from the Tonykart recommendations. With hindsight this might not have been a great idea: it took a long time, Junior got hacked off holding the seat in place and I don’t think I ended up much more ‘optimal’ than I had started out. And I forgot about the weights when putting the seat back on.

Ah, the weights… the highlight(?) of last week!!! Having weighed Junior at Llandow I reckoned we needed 7kg of lead and the black restrictor to put us at the correct race weight. I already had 3kg that came with the kart and I bought a 4kg lump for £15 from the forums, it just needed fitting – 3kg went on the side of the seat (low on the brake side to offset the engine weight). After hammering the lead weights flat so as to fit flush to the seat, it was pretty straightforward. The 4kg weight had other ideas – I hit it flat and held it in position to mark the drill holes. My marking pencil had disappeared so I went off to fetch it, holding the lead in place against the seat in one hand. As I went back outside the lead slipped and I instinctively (and stupidly) put my foot out to break the fall!!!!!!!! Painful was an understatement.

I got back from hospital just before 2am with very swollen, very sorry looking broken toe. Funnily enough, I haven’t done anything on the kart since! I have a injured toe photo that I took in A&E that was very popular with my Facebook friends but I’ve decided not to post it here 😉 I am hoping to be fit enough to run Junior at Clay on Saturday but push starting is an obvious concern. Fingers crossed…

Cost of an especially damaging 4kg lead weight: £15

Total spent so far: £2,925

Engine rebuild

I’d been considering getting the engine rebuilt for some time; I bought the engine with ~3 hours on it prior to our test/purchase day (onto which I added a couple of hours just in case) and we had put 6 hours on it following the ARKS test. Given the recommended rebuild time of 8-10 hours I thought it best to err on the side of caution and book a rebuild.

The big question was who to use? The previous owner had had both his race and this practice engine (I bought the latter) rebuilt by Dave Litchfield – one of the best know engine builders in the country but I didn’t think I was really in a position to justify the additional cost of posting the engine for it to be rebuilt by the man lots of race teams use (not to mention I think I might have been a little out of my depth in any service discussion!). Looking at the numerous local options, I had heard good things about all three of the builders I was considering. I assumed that the quality of rebuild would be pretty much the same given the limited amount that can be done with a TKM engine so in the end it came down to convenience: I’d just finished a day at Clay and it was easy for me to leave it with Lee Rennison, the ARKS examiner at Clay (no conflict of interest here I hasten to add – I didn’t mention the rebuild until *after* the test!). He offers a rebuild service and I figured it would a) save me cleaning the engine when I got home, b) save me having to take or send it anywhere and c) potentially offer some local support if I ran into any engine issues at the track. And he’s a really nice bloke too!

The rebuild took a week and I picked it up today. The engine was in really good shape so I could probably have gotten another couple of hours in. Had I not lost the receipt at the track I could have told you exactly what I had done but it included new top and bottom-end kits, gaskets, bearings, a piston and three carb rebuilds for a [relatively] palatable £230. I am sure Junior will enjoy running it in later this month!

Whilst we were there I attempted to make Junior watch the drivers practising ahead of tomorrow’s race fixture and make some mental notes of the race lines. He never seems to listen to me, nor anybody else for that matter but I really hope watching a constant stream of drivers taking a decent chunk of kerb through The Esses might sink in. We’ll see…

Cost of engine rebuild: £230

Total spent so far: £2,910 (starting to regret keeping a running total now…)

Practice 6: ARKS test

Thursday night was a bit of a rush, it being the first dry evening since the kart got soaked on Monday – I had dried the kart as best I could (given the constraints of working on a kart sat on a camping trailer inside a single garage) but there was still a fair amount of moisture around the engine mount so I chose to remove it and make sure everything was clean and dry. Not the best time for a first solo removal of the engine and exhaust perhaps but it needed doing. I also had to reset the front width after widening it at Llandow and I got as much ready for the day as possible: changed the sprocket, mixed some new fuel and slightly overinflated the tyres so that I could tweak them in the morning.

We got to Clay Pigeon Raceway about 20 mins before the track opened, signed in and were told to have a few runs and the ARKS examiner would come and get us when the time was right. I had been a bit worried on the drive down about the possibility of a repeat of the starting difficulty we had last time so I was relieved when it started first time. I ran my normal wheel, hub and chassis bolt checks and, unusually, we were out for the first session 🙂 We had a stuttering start though – Junior came in eight laps reporting the back end felt loose. I wondered if this was a tyre pressure issue so I dropped them down a notch. Second time out he complained it felt even worse! With his hesitancy from Llandow in mind, I assured him that nothing was loose so there was no safety issue and sent him back out to give the tyres a good warm up and see if the handling improved. I widened the back end by 5mm on each side when he came back and, from then on, he was happy with the handling and was soon pushing it. It was only during the fourth session that I realised the ARKS instructor was marshalling so that he could watch Junior, who by this time had beaten his previously best lap time from our February session. The instructor was more than happy with his speed and it was at that point I stupidly commented on it being nice to have the kart running without issue. No more than two minutes later, the kart is parked up on the exit of Billies and Junior is inspecting the back end. I made for the trolley park.

This was an interesting one: not only had the chain had come off but the sprocket was hanging on by a single bolt and one part of the sprocket protector was sitting on the axle, next to the chain. I had lost two of the three bolts from the sprocket carrier although one was bent and wedged in the back of composite chainguard. There were no nuts, including those that separated the sprocket from the sprocket protector (on which the fixing holes were now very worn to the point of being largely useless). I had lost parts on track yet again… 🙁 This was and still is something that I am desperate to see the end of – this particular problem was a new occurence and I can only assume that the nuts on the outside of the plastic sprocket protector had come loose. Just like the exhaust screws, it seems that once one goes it’s only a matter of time and the sprocket nuts were not nylocs, nor was I checking them between sessions. I removed all the relevant parts – there was composite chainguard ‘dust’ all over the engine, chain and chassis. The chainguard itself was cut up and the sprocket had worn on side of the teeth. I disposed of the sprocket, patched up the back of the chainguard with tank tape, bought six new sprocket carrier bolts (we – and every other kart I have ever looked at – had only three bolts in place before now) and cleaned everything up. We missed two sessions but at least it gave us some time to have some lunch.

As we were ready to head out again, Junior was called for his ARKS driving results and theory test – the only comment was that he needed to use the kerbs in the Esses and he got all his questions right in the test, meaning he passed his test 🙂

We made the most of the remaining four sessions, running until we were kicked off at 5pm. Junior had some fun racing with a couple of his friends he knew from Teamsport Bristol – one a Senior Max, the other in a Mini Max which made for a surprisingly entertaining spectacle and he was chuffed to post a new fastest lap of 36.92s, especially as his tyres were probably making a farewell appearance (they were used when we got the kart and he’s since done over 400 laps on them!). All in all, a good day – ARKS test passed, 157 laps ‘bum-in-seat’ time and a new fastest lap, only tainted by the sprocket bolt problem although I am now running six bolts (three of the holes on the sprocket and sprocket protectors are now badly worn) and checking them after each session (they do need tightening up every time, even with nylocs – I wonder if it is the plastic sprocket protector that doesn’t really allow for a firm tightening of the nuts).

Cost of day: £12 petrol, £7 petrol for 5l super unleaded for the kart, £85 ARKS test fee (including track practice), £1.50 for 6 sprocket carrier bolts

Total spent so far: £2,680