Greg - AMCC R4 & R5 '10

AMCC Protecta Club Champs Round 4 and Round 5

March 7th, Round 4 at Pukekohe Park raceway. It had been almost 3 months since I had raced the Yamaha R4 but over the summer break I had talked to a number of people and had attended two test days at Pukekohe. At the last round in December the bike had shown promising performance over 12,000 rpm but below that, performance was poor so I decided to follow some advice from Kevin at Kelford Cams to try the shorter duration standard inlet camshaft. The result was that maximum horsepower moved from 15,500 to 15,300 rpm but more importantly the motor was pulling a lot more strongly from 11,000 rpm. This was confirmed on Triple Z's dyno showing wider power delivery at the top end too. We didn't have enough time to do a full remapping of the air/fuel ratios but I felt quite positive that the bike would be easier to ride on March 7th.

The weather was dry and we were the 2nd class out for practice and qualifying. I was feeling very positive and decided to go out early before anyone blocked the track and went as hard as I could on the relatively cool track to qualify up front. Much to my surprise, no one passed me for the whole session and when the results were published I found myself 4th on the front row of the grid. Bill, Geoff & Mark were in front of me but there was only 0.9 secs separating us all so we were set for a competitive day.

Race 1 and I got off to a reasonable start only dropping back 1 row which I made up by the end of the back straight. By the next lap I had caught up to Mark and followed him getting closer on each lap. Bill & Geoff had cleared off into the distance and on the last lap I came alongside Mark at the end of the back straight and got around the hairpin to take third place. Unfortunately I came out of the corner in second gear not first and had no drive. Mark zapped past on the inside and took the chequered flag along with my third place.

Race 1 had been into a strong head wind so I decided to lower the gearing by one tooth as I had only hit 14,500 in 6th instead of the usual 15,000+. In spite of this I had achieved a new best time of 1 min 7.09 secs chasing Mark, 0.7 secs faster than in December.

Race 2 and I had a reasonable start but the strong head wind had disappeared and now I was hitting the rev limiter in 6th gear and the best I could do was sit in behind Vaughan on his SV650 as I watched Bill, Geoff & Mark leave us behind...5th place that time.

Race 3 saw me go back to the original gearing but now there was oil all around the track from one of the Post Classics, so no chance to improve my lap time and I followed Mark for the whole race to finish in 4th again.

Still the points were good enough to keep me in third place in the championship with the last round to follow in April.

The last dyno run had shown that there were still a lot of peaks and troughs in the power curve so I decided to get the bike over to Gary at Dynotech. He has software that links directly to the power commander fuel injection controller and will automatically adjust air/fuel ratios across the rev range and at various throttle openings.

Gary worked his magic and found another 4 peak horsepower but more importantly he managed to fill the troughs lower down in the rev range to improve the overall power curve by 20%.

April 24th, Round 5 and it had been raining overnight but by the time we got onto the track for our practice session there were only a few puddles and some mud on the track at turn 1. I went out in the first bunch of riders and soon got to the front and tried to go as fast as I could but backing off a bit for turn 1. After about 3 laps I was slowed by a few slower riders and our session was over. I didn't think I had done particularly well as the track was cold and turn 1 a bit messy but the bike was running beautifully...pulling well over 15,200 in top gear plus being a lot stronger in the mid range.

When I looked at the qualifying times I was surprised to see I was in 2nd place only 0.3 secs behind Bill with Geoff 0.4 behind me. Unfortunately Mark wasn't able to make the last round.

Race 1 and my start was a lot better, 4th into turn 1 behind Greg Page's SV650 which I soon passed down the back straight to pull in behind Geoff. I had a little more top speed than Geoff but I had a lot of trouble getting down through the gear box after turn 1. Three laps in a row I came onto the back straight in too tall a gear which let Geoff pull away and I finished third with a new best time of 1 min 6.98 secs.

Before race 2 I adjusted my gear lever position to try and solve that issue. Race 2 and again I was 4th out of turn 1 and hot on the tail of Geoff down the back straight. On the second lap I had enough pace to slip stream Geoff and get past at the kink and just managed to hold him out under brakes into the hairpin to secure second place. I had to get in Geoff's way a bit to stop him getting me back and that slowed us both allowing Bill to get a jump. I put my head down and tried to catch Bill but on the third lap I failed to get into the right gear again and Geoff passed me under brakes up the inside at the hairpin. By this stage we were lapping the slower guys and I had to slow for one. I tried hard to catch Geoff but the chequered flag came out one lap too early and I finished third again.

Race 3, and I was psyched up to have another go at Geoff as I was sure I'd make the pass stick this time. I went out on the warm up lap and as I came out of the hairpin, the motor died just as if someone had turned off the ignition, a second later it fired up as if nothing had happened but then it died again then restarted. I decided it wouldn't be safe to race under those conditions so I left the track and rode back up the pit lane and that was me for the day. Geoff went on to beat Bill in that race.

Overall the day had been a lot of fun and Gary's dyno work had paid off. In the earlier rounds there was no way I could match the performance of Geoff's & Bill's bikes but now I can probably beat them both if I ride consistently. A new personal best (when everyone else was going slower) and I managed to hold onto my third place in the championship which is my highest placing in 12 years of racing.

Over the winter I'll try to squeeze a bit more power out of the engine as it's still only 10:1 compression ratio.

Thanks again to our sponsors, Pirelli Tyres, Motul Oil, Henderson Yamaha, SSS Lodge, and Mark Percival.

Hope to see you over the winter at Manfeild, cheers, Greg

No Hair Racing

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