We’re just back from a rather frustrating weekend at Mallory. I should have known better really. We didn’t go there last year as it was right in the middle of the time when Anthea was being replumbed. However, a lot of the RGBers that did go didn’t have a fun time of it.
The experience this time started last Wednesday. We traipsed up to Mallory for the Wednesday morning test session. As I hadn’t been there for a couple of years it seemed sensible to see what it was like with the new engine. Of course, it rained and rained and rained. After all, it’s July, isn’t it?
First session out wasn’t too bad and I took it very slowly at first. After a couple of laps I started ramping up the speed and the misfire reappeared. It appeared to be the exact same misfire that we’d “cured” at Brands by replacing the engine. So, it was back into the paddock for a morning of frustratedly fiddling about. At least this time we managed to reproduce some echo of the problem in the paddock but nothing seemed to be completely definitive. Problem was that after the first session the rain got even worse and any trips out on track were not in any way representative of race pace anyway.
So, I left Mallory thinking the worse. I did have a couple of vague ideas at home and did a bit of desultory fiddling with the car but nothing obvious cropped up.
So, come Saturday afternoon we were heading back for Mallory not really expecting very much. At least the weather forecast said that the Sunday could be fine. We could hope…
In fact, Sunday did dawn fine. First thing I changed the engine’s primary injectors for some spare ones that Andy had brought with him. I can’t admit that I was feeling at all confident about it though, as the ones I’d taken out seemed pretty perfect.
And, so it turned out. Out on track for qualifying the misfire was back. However, I flogged around for a few laps and managed to at least post a time that wasn’t right at the back, just about two thirds of the way back.
So, with the bonnet up again, I was staring frustratingly at the engine with it idling happily in the paddock. I noticed a bit of loom tape fluttering away at the rear left of the engine, in the thermal coming out of the catch tank and off the exhaust headers. Not having anything better to do I reached in to neaten it up and on the way in brushed the back of my hand on the wiring to the cam position sensor and the engine promptly stopped!
Some more fiddling around showed that there was a problem with this wire. On closer inspection one of the wires had fractured inside the insulation. As things wobbled around, while driving around for example, the wire was making and breaking contact, very likely leading to the misfire! The break was right at the very edge of the plastic housing of the sensor, so not at all obvious. I hunted around the paddock for a spare sensor but didn’t find one, well one that worked anyway. So, I cut away the plastic of the sensor to expose a little more of the wiring, and soldered the existing lead back again.
The engine seemed to run fine now, at least as far as I could tell. However, I was hopeful of a decent race.
I should have known, though. After all, it was Mallory.
The start went well and for the first lap or so it went well and the engine was clearly actually working. Then, I noticed that it kept hitting the rev limiter. When I went past the pits, flat in 6th on the limiter it finally dawned on me that the clutch was slipping. Rats! I’ve never actually done a clutch before. It could well be that the technique I’ve had to adopt for getting the CBR1000 off the line, which involves a certain amount of clutch slipping, had provoked the problem.
So, I retired back to the paddock. Again…
I didn’t have any spare clutch plates, but Andy had a set of uncertain provenance that we fitted with zero time to spare before the second race. There was so little time that all I could do was drive the car to the assembly area without waiting to see if it actually worked. It seemed OK though.
However, out on track and it started slipping again, just a bit. Then, exiting the hairpin I completely lost drive so I pulled into the chicane just there that the bikers use and watched the rest of the race from the marshalls’ post. Sigh…
Later on, it was clear that something was clearly dead in a big way as you could now start the car in gear and it would idle happily without actually moving! The most obvious culprits were clutch, gearbox, driveshafts or diff. Realistically though, the clutch has to be top of the heap.
I’ve now got the car back in the (shiny and clean) garage. A short inspection shows that the diff and driveshafts are going round as expected, so when I get a moment I’ll have another look at the clutch.
Rats…!