Tag Archives: Anglesey

Anglesey racing report: May 16th and 17th 2015

Anglesey is a long way from Devon. This became more and more obvious over my 6 1/2 hour traffic-jam-filled journey to the circuit on an inclement Friday afternoon.
Roger had cancelled because of the flu. He sounded dreadful and had done for some time. His voice had become more and more hoarse and he couldn’t sleep for coughing, propped up on the sofa was the only way he could get any rest. His lack of spleen doesn’t facilitate recovery from viruses as far as I understand, being an important part of the body’s immune response. It has to be bad to miss a race meeting too.
So it was that I found myself erecting my tiny backpacking tent in what I understand now to be good Anglesey conditions: unrelenting high winds but without rain.
The wind is something else. I had heard about it but now I can really imagine what it could be like. The circuit is right on the Atlantic and the drive through Anglesey itself starts to give clues to the general conditions. A lack of trees and the prevalence of very gnarled bushes with what scant tenacious foliage they had swept at an acute angle an indication of life on this coastline.

Saturday was clear and dry. I went through Scrutineering and signed on.

Practice gave me my first taste of what was to come. When you rounded ‘Church’ corner in the middle of the long back straight you hit a wall of wind which made me think that the bike was seizing up. Then, on the third lap, it did seize up, though I caught it pretty quickly and rode back though to the paddock.

I took the needle up a notch and got ready for the first race.
Angleseymap2012

My first race was the ‘up to 63 unlimited’ which is my second choice event to give me another couple of rides. It’s almost collapsed as an event at the moment and there was only one other guy entered in this on a BSA twin. I don’t know what happened but I guess the people have all entered different bikes in different classes or simply stopped. The ‘up to 48’ class is better supported. It’s not a big deal as long as you are sharing the grid with a mixture of other classes and so there were plenty on the grid. All far too powerful for me, but I was starting on the back anyway just to see how it would run.

It was better, but it still nipped up accelerating out of Church corner into the back straight. I nursed it round and went back to the van.

A Scott owner, Bernie Dunmore, offered his assistance. We’d never met before but he spent the following few hours helping me get to the bottom of the seizure issue. It was puzzling because it was theoretically running richer than the optimum needle setting chosen on the dyno, and they seemed to think that I’d be running rich in the real world even at that setting. The wind was a considerable force though and maybe that was causing the engine to have to work so much harder that the engine was getting too hot? The timing had changed also, possibly jumping a tooth on the slightly-under-tensioned belt when it nipped up… the momentum of the rotor forcing the jump. I checked the fuel flow to the carbs and thought I noticed the fuel flow to one of them increase as I moved the feed pipe. Was it possibly an air lock in the flexible hoses? In plumbing, air locks can cause all kinds of problems. Maybe it was this? For good measure, I thought I’d go up in the heat range on my plug. Ken Inwood was there and I bought a couple of NGK’s, heat range 8. That’s two up from where i was. It shouldn’t be this but I needed to cover all the bases.

By this time it was the end of the day with one race left… I got out and it didn’t seize up. It was obvious that the torque I’d lost at the start of my rev range since changing from Methanol was causing me a problem as the engine wasn’t able to pick up in third when shifting up from second at 5000rpm as I rounded Church corner into the wind. It was bogging down and I was losing a lot of time here. I started to learn the track at last though and really enjoyed this last race of the day. The rear tyre, already pretty worn out by the end of last year, danced its last dance and I could feel it drifting though ‘Rocket’ but mostly through ‘Peel’ which is before the drop down the hill toward the left that leads into the corkscrew. I really enjoy racing tyres when they are finished… you can’t really carry speed because they’re not gripping any more but you can feel them drifting far earlier and it’s great fun. Fortunately, I’d arranged for Roger to send me up a spare with another competitor (as well as a new final drive chain from ‘The Chain Man’, Andy Forsdick)
I changed the gearing, just by a tooth on the back, to try and get into third before I hit the wind and then I changed the tyre. Unfortunately I ended up pinching the tube so it was a case of waiting for Ken to return in the morning.

I made a sandwich for my tea, and crawled into my tent.

Sunday morning. Overcast and windy.

I was first to get to Ken and he changed my tube, very graciously not mocking me for making a mess of doing it by myself. He did note however that the tube had been too big for the 90/90 profile of the Avon roadrider, undoubtedly a legacy from the days when we were running 3.25 section GP’s.

I think I had a race first thing, which was the big class. Again I just started from the back and just scrubbed my tyre in, taking it steady.

Things were better but still it was a struggle to pick up on the back straight. I resolved to just do the best I could, and investigate further when I returned home.

The next race came around, which was my ‘up to 48’ class. I was feeling a bit more like it by now and though I didn’t get a great start, I was suddenly at the back of some of the ‘up to 1983 Japanese 500’ class with whom we share the grid going into the ‘Banking’, the exit of which leads into the first part of the straight that leads to Church. The brakes are good on the Super Squirrel and I passed a couple on the brakes and got through the corner well. People were passing me down the straight at a fair clip, but it did seem that I could make ground going into Church and then also at the end of the straight into the very tight left hander. It was like this for a couple of laps, where I was hauling people in from this corner to the banking and then simply losing it as bikes came past me on the straight like I was standing still. I was especially hunting an RD 400 and a CB 450, I never got to the 450, but the RD 400 was incredibly quick on the straight and went past like I was standing still. I really pushed to keep getting past him on the rest of the circuit and in the end pushed too hard, losing the front end into the tight left at the end of the straight. I saw him later and he said that he’d thought I’d never get round after I’d outbraked him on the inside going into this corner. I said that I couldn’t argue with him because I didn’t make it! My fastest lap was quicker than the 5th placed Japanese class guy (on the CB450)but I would still have been second in my class to Tony Perkin on his Rudge 500 who was 2 1/2 seconds per lap faster than me… absolutely flying.

The radiator was damaged, the front mudguard and the right hand footrest but little else. The radiator was unfortunate as it’s never taken a hit before but sometimes these things just don’t fall in your favour. You have to push when you are trying to race an RD 400 on a vintage Scott.

damaged radiator and footrest... unfortunate but could have been a lot worse.
damaged radiator and footrest… unfortunate but could have been a lot worse.

In all, I really enjoyed Anglesey but left realising that I still had a way to go with the new set-up. I think I need more compression, and some more development to iron out the problems with the fuel system. I was due to take the bike to Roger’s in Leicestershire in readiness to take both bikes to Cadwell Park on Tuesday so that Steve Plater could do some testing. I thought maybe if I got home to Devon I could sort out a repair on Monday morning and drive up to Cadwell on Monday evening to be there for the test.

It would be a lot of driving but I thought I could do it. I said my farewell to Anglesey, resolving to return and headed home.

A morning on the dyno with the Scott

I really enjoyed taking the Scott to the dyno yesterday. It was the first time I’d ever actually booked a proper set-up rather than a single run. I suppose cost was always an issue but I have realised how useful it is to be able to see the results of the changes you make and a proper session allows you to experiment with many different settings and see how each affects the result. It’s a bloody good way to see what affects your power output, and how. The cost is similar to me going to a trackday, and there’s no way I’d have gained the same information from that.
Of course, you need to have someone who can run the dyno and can interpret results. GT motorcycles of Plymouth have a very interesting division called ‘Performance Engineering‘ that specialise in rebuilding, restoring and tuning Honda racing bikes, and it’s these guys that run the dyno. Steve is highly knowledgeable and experienced in getting the most from an engine on the dyno. I’ve done my previous runs with him, but yesterday he was able to really show me the benefits of a dyno setup. Steves colleague Andy, another two stroke fanatic, was assisting and as the Scott’s engine note became crisper and cleaner they were both obviously enjoying the experience. Ok, so the Scott doesn’t put out the sort of horsepower as an NSR500, but it did sound so very good .. and maybe the 4.5% Castor mixture helps too!

Anyway, I realise that for many people the idea of going on a dyno seems a bit extreme but carburation and ignition set-up problems can persist for years if you don’t seize the opportunity to really get to the bottom of them. I don’t want to spend my time at a race meeting or a track day like the Beezumph constantly messing around with jets , needles and timing just to try and get somewhere close. You’ll always have a certain amount of tweaking.. but at least I feel like I am quite close with what was a completely unknown arrangement.

So, What happened?

I’d fitted the 1″ carbs with 320 main jets for a start. The needle was on the bottom groove, so all the way up. I’d figured that it might be rich but I had no desire to start from the other direction! The timing started at 22BTDC.

It was rich. Our runs followed the following order:

1: down two mainjet sizes to 300
2: down two mainjet sizes to 280
3: drop needle one notch
4: drop needle another notch
5: drop mainjet one size
6: raise mainjet one size
7: change timing to 23.5

You can see the graphs here for the final results compared to the very good curve I produced when I first set up the bike up on methanol.

Torque curve for the Super Squirrel racer.
Torque curve for the Super Squirrel racer.
horsepower curve for Super Squirrel racer
horsepower curve for Super Squirrel racer

The exhaust temperature sensors were really useful and we were able to monitor for significant changes with any modifications to setup that we made. The final high was around 530°C. Always increasing by about 30°C to 40°C the moment you shut the throttle off… interesting stuff.

Type K thermocouples read by simple meter
Type K thermocouples read by simple meter

You can see that the Torque curve starts later and then increases at a very high rate. It may be that this lost section (around 400 revs) at the beginning is retrievable by playing with cutaways, but the gain in midrange torque is very good indeed. That may be down to the improved gas flow in the head. It loses to the methanol later in the rev range, about 4000rpm. The methanol torque stays high all the way to 5000rpm where it suddenly falls off a cliff. The new curve hits a higher torque figure but tails off more noticeably. However, the fact that suddenly I started to have more revs was a bonus (as long as I can get the 400 back at the beginning!). I think Steve’s attitude was that the extra ‘over rev’ was extremely useful as the engine was able to keep pulling longer because of it.
As far as I understand, the fact that I increased the head volume, lowering the compression ratio might have created the conditions to encourage the engine to keep revving.

As the torque was lower late in the new curve the maximum power is less than before, but I’m not too concerned about that at the moment. It might be that I could do with the shape that I have created in the combustion chambers, but with a high compression ratio. It would be worth experimenting with heads sometime.. but not now. It may even be that the carb size is a little small, and I’ve never done any further tests with the exhausts but short of changing the slides to try a higher cutaway I’m now looking at actually using it! It felt really smooth and sounded great.

So, this afternoon I posted off my entry to the British Historic racing clubs second meeting of the year at Anglesey on the weekend of the 16th and 17th May. Roger is going too. I’ve never ridden Anglesey before but I’m really looking forward to it.