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Early February 2010
February 10, 2010 by mike.cox
P.O. BOX 28300
KENSINGTON.
2101.
Website. www.sahmg.co.za
Terry Barson’s email.
Early February 2010 newsletter.
Schedule of events.
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Date.
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Day.
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Event.
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Location.
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February.
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6-7
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Day of the Champions
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Killarney CT.
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February
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13
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Day of the Champions
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East London.
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March.
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6
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To be advised.
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April.
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10
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Zwartkops
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May.
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1
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To be decided.
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May.
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29
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Zwartkops
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June.
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19
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Wednesday 16 June is a holiday.
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East London.
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August.
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7
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Phakisa
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September.
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18
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Kyalami
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October.
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16
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Zwartkops
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December.
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4
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Zwartkops
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Most of these events are in conjunction with classic / historic car events.
At Zwartkops we will get a practise and two events. The entry fee is fixed at R250.00 per Zkops event for the whole year.
The SA TT.
Preamble.
The limeys left the UK before 6am Wednesday which meant at least a 3am leave from home, if not earlier?
Caught a connecting flight in Amsterdam and arrived Wednesday night around 10.30pm and by the time they got to Haarties where they were sleeping, it was close to 1am and they hit the sack after 2.30am!!
Phil Read arrived a day before and stayed a few days with John Boswell.
Well for me personally it started a few months back.
Clive asked me to assist with organising some of the program, mainly for HMG but it turned out to encompass quite a lot more.
But the actual hard work started Thursday morning.
I had promised I would assist the overseas guys with a drill, extension; tools etc and help get their bikes out.
At the track by 9am and waited a bit for the UK people to arrive.
The unloading took a few hours with getting crates out of the 40 foot container and then assembling the bikes back together.
Practise is on every Thursday with Dave Klette, who runs the practises as a business. I spoke to Dave and he agreed and allowed anyone of the UK guys to join in if they wished.
Thursday evening was our hosting of the braai for the overseas visitors. We had 47 people book to turn up but as per normal over 60 actually purchased braai tickets. Many of them we didn’t know or forgot or didn’t bother to book. Just, just had enough food.
A good evening was had by all I believe and the UK guys loved the braai. I loved their comments about the pap. ‘What’s this white stuff? Is it for putting wallpaper on the wall?’ Eat it and shut-up.
We presented John Boswell with a plaque from HMG honouring him as one of the founding members and for his efforts and assistance for many of our members over the preceding years. We also made him an honoury member. Long may he continue riding and assisting us with his vast knowledge and amiable manner for years and years to come?
I stayed from Thursday night through to Sunday afternoon, as did John Boswell, Geo, Rob, Marianne and Gary Boksnot. Also Ian Groat and Jimmy Guthrie stayed over, but sort of stayed by themselves.
Trevor and a couple of others arrived Saturday and stayed over as well.
We had a couple of braai’s and a few beers along the way.
Friday late afternoon I could see a storm approaching, and casually mentioning this to the UK guys, still left working on their bikes, that a typical SA thunderstorm would hit us in an hour or so.
Actually I was slightly wrong because the typical storm was anything but.
The roads turned to rivers and then floods and the lot headed to and through the Bridgestone pits in a torrent. So much so, we were under 70mm of water within 15-minutes. The tents were hastily picked up and moved but it was a waste of time as everywhere became under-water. The souties loved it. 4-hours later the ground was dry again.
I heard later that half of Joburg was floating towards Pretoria?
We had a bike display under the Bridgestone roof Saturday which moved up to the main pits Sunday early.
Saturday not as good from my point of view as many local teams with gazebos arrived, put them up wherever and little concern for anybody else, the UK bikes and riders ended up jammed inside and no easy method to get out for the events.
A pity as I assumed one of the main reasons was to show these overseas fabulous bikes with their equally famous riders to the general public?
Short sighted attitude from my perspective because if you piss off the UK guests, they don’t come again, and then what?
Phil Read and Jim Redman spent time together going over old times and must have signed 1,000s of autographs. I saw a few bikes with Phil’s signature on the seat hump.
I would like to thank John Boswell and Roger for providing accommodation for Phil while he was in Joburg.
Alan Cathcart also drew some interest. Alan writes for most if not all motorcycle magazines throughout the world and I am sure we might get some recognition in the near future.
BikeSa and Two-Wheels were filming and interviewing throughout the weekend and Dave Petersen and Simon Fourie were seen from Thursday night through to Sunday.
The UK racing guys if you’re not into racing were not that well known by the general public. But I must have been asked 100s of times ‘which one is Steve Plater, which one is Mick Grant?’ Steve only rode the Isle of Man once before winning it the second time. And his average speed was just under 132 miles per hour. Just pipped by John McGuinness who won last year.
Sunday all the planning put together about no parking vehicles in front of the pits and keeping to your pit allocations went out the window for everyone else. HMG were the only people who actually did as asked. The rest was a free for all. I thank everyone who did as we requested.
Overcast and or cloudy all weekend until early midday Sunday when the sun started beating down and it turned hot and humid.
The Classic Club came out as an official run and the HMG were able to give each CMC member a free ticket to get in.
Practise went well. So did the two events. A couple of breakdowns, including the Souties.
Alan Walker bit the dust in turn two and the Ducati a little worse for wear. But he had two more bikes as spares, so maybe not a major problem.
We had one of our members also go down in the same corner (turn 2) but in a different event.
Les Van Breda on his Suzuki GP bike was having a ding dong battle with Wayne Heasman, also an ex SA champ, but just couldn’t get by.
The back tyre (a Battlax) couldn’t put the power down. I offered him my new Avon back tyre for the Ducati that just arrived, if he would replace?
Les was over the moon with the difference and had a grin the rest of the weekend. He said ‘I don’t care what this tyre costs, I’ve never had this much fun on this bike, ever!!!’
I think one of the past, older champions will be joining us. Lives in Durbs and rode a Honda 500/4 with a piss-pot helmet on.
I had my clutch master cylinder pack up as I started the last event. DON’T BY CHEAP EVEN IF ITS NEW, I just got the bike started and pogo'ed out of the pits and did clutch-less changes thereafter and remained way behind at the back of the pack on the warm-up.
When the flag dropped I let them all get going then came around the last corner and took off after them. No way I could do a standing start.
Took a bit of catching up and got past a few slower bikes, great fun.
Must have been dreaming about the last event when I hit the sack Sunday night because my wife said the bed looked like somebody had a fight under the sheets the next morning?
Got another master cylinder from Robbie Godwin a week before for the front brake which has been giving me kak for over a year now. But I didn’t know it was 100% the master cylinder problem until now.
Fitting it and in the practise I could see the brakes were 100’s of times better than before and no fading.
So much better, I was hitting the brakes as per normal just before the 100 metre marker, coming almost to a stop and having to accelerate again. I could miss the 100 metre marker and only at 50 metres or less slam on the brakes and dive into the corner. What a difference working equipment makes!
Must have knocked off ½ a calendar from my lap times?
Nobody from HMG rode Saturday, apart from ex champions who belong to us.
John Boswell is bringing in master cylinder units as well as rear master cylinder’s. Give John a call to get pricing.
Do it again? Well maybe not the 4-days again, but for sure Saturday and Sunday.
Committee members, Derek and Etienne assisted with rollers, issuing tickets, standing at the main gate etc.
Special tanks to Penny for doing all the paperwork.
Rob Godwin for bringing the Gazebo.
And to anybody else I left out, sorry!!
The overseas contingent left Monday morning in hired cars at 5am for Plettenberg Bay for a few days, then onto Cape Town.
They will then ride Saturday and Sunday at Killarney, then do some sight seeing before leaving for East London.
By the middle of February there’re back to the land of chills!!!
I personally think they enjoyed themselves. Bit of a rush though.
Dave’s posted hundreds of pictures on his website, so please go and have a look and purchase if you like what you see.
The middle to back markers.
Many of the quicker HMG riders and their bikes really don’t get to see the camaraderie and effort the majority of the HMG riders possess?
With engine outputs all very similar, riding skill plays an important part in any event, a missed gear-change and he goes from entering first into a corner to coming out last in the group he is riding in.
Lines through corners and sweeps are very important and being tucked in means a slightly better aerofoil shape and therefore slightly higher speed.
The bikes and riders are usually but not all are candidates for the 100+ club, with drum brakes and 4-speed gearboxes.
Horsepower is often 1/5th of a front runner, and with technology still in many respects in its infancy, there is no chance these riders and owners could even think of keeping up with the front of the group.
But saying that, some give a good account of themselves, especially in the corners where horsepower is not such an advantage?
And older machines need some fettling from time to time, often between events.
Which brings out the stools, spanners etc and a good chinwag and improved relationships?
I remember reading about Phil Read and one of the UK bike magazine journalists who had a ding dong battle with Phil on a 500 Manx and the journalist on a R1.
Even with this massive horsepower advantage I seem to remember Phil beating the R1.
But the track was wet though.
It would be nice to get a bit of history of members machines, I know a couple sent me information, but I need more for the newsletters.
Technical.
Engine Performance
To get more performance from an engine, you have to burn more fuel. Sounds simple, yes?
But to do this you must have air, specifically oxygen, to support the combustion. The fuel is no problem. If that was all there was to it, we could put a huge fuel pump in the bike that would pump the tank dry in seconds.
The problem is with getting enough air in to support the combustion.
Air - fuel ratio is expressed as ratio by weight, and is approximately 15: 1.
If we expressed it by volume (air weighs a lot less than petrol), it would be around 10,000 parts of air to one part fuel.
So how do engine parts affect performance?
- Air Cleaner: A less restrictive air cleaner, or no air cleaner and a velocity stack, or an air cleaner which takes in cooler, denser air, will improve the amount of air entering the engine.
- Larger carburettor reduces the choke restriction at high speed.
- Intake Manifold: Less restrictive intake manifold /s reduce restriction at high RPM, but can hurt low RPM power by reducing turbulence, and therefore reducing mixing of the air and fuel, and therefore reducing vaporisation of the fuel, and hurting low speed power.
- Big Valve Heads: Again reduces restriction, but only at high RPM.
- Free Flowing Exhaust: Headers, large pipe, dual exhaust, increase breathing by reducing exhaust back pressure.
- Camshaft: A long duration, long valve overlap, high lift camshaft, will increase high RPM power, but will reduce power at low RPM.
- R.P.M.: The higher the speed the engine runs at, the more power strokes per minute it will have, and therefore more power. Balancing the reciprocating and rotating assembly allows the engine to turn higher RPM safely without blowing up.
Now the cylinderhead and camshafts for 4-strokes do more for increasing HP than any other cheap mod you can do.
It will turn a docile bike into a totally different machine, but at a cost to torque and low grunt.
Read on….
Regarding cams, they are rated by duration at some defined lift point. As slow as the valve opens and closes at the very beginning and end of its cycle, it is difficult without expensive measuring equipment to find exactly where it begins to move.
Many tuners specify measuring the start and close of lift by opening the tappet clearances to 20thou to get rid of the very small movements of the valve. Also they say a valve doesn’t flow properly until the valve is off its seat by a couple of mm’s.
Looking a bit further at the timing points, the first one to discuss is the exhaust opening point. We have all noticed the different sounds of performance cams, with the distinct lopes or rough idle. This occurs when the exhaust valve opens earlier and lets the sound of combustion go out into the exhaust pipes. It may actually still be burning a little when it passes out of the engine, so this can be a very pronounced sound.
The next point is the intake opening. This begins the overlap phase, which is very critical to vacuum, throttle response, emissions and especially, petrol mileage. The amount of overlap, or the area between the intake opening and the exhaust closing, and where it occurs, is one of the most critical points in the engine cycle.
If the intake valve opens far too early, it will push the new charge into the exhaust manifold.
If it occurs too late, it will lean out the cylinder and greatly hinder the performance of the engine. If the exhaust valve closes too early it will trap some of the spent gases in the combustion chamber, and if it closes too late it will over-scavenge the chamber; taking out too much of the charge, again creating an artificially lean condition.
If the overlap phase occurs too early, it will create an overly rich condition in the exhaust port, severely chewing up the petrol usage. So, as you can see, everything about overlap is critical to the performance of the engine.
The number of degrees in cam shaft rotation that the intake & exhaust valve are open at the same time (The point in which the intake valve opening point BTDC and the Exhaust Cam's closing point ATDC).
Increasing the number of degrees of overlap tends to move the power band up the RPM band but you will sacrifice low end power. Increasing the overlap can increase peak power, but only if the exhaust system is efficient enough to properly scavenge the cylinder.
Decreasing the overlap tends to boost lower rpm performance.
The last point in the cycle is the intake closing. This occurs slightly after Bottom Dead Centre, and the quicker it closes, the more cylinder pressure the engine will develop.
You have to be very careful, however, to make sure that you hold the valve open long enough to properly fill the chamber, but close it soon enough to yield maximum cylinder pressure. This is a very tricky point in the cycle of the camshaft.
Diagram below should help in the understanding, or maybe not depending on which side of town you live?
A lot of tuners say 100 to 110 degrees of overlap is optimum?
You get nothing for nothing.
I remember the work done on Rabid’s Matchless a few years back.
Fitting a larger carburetor required a lot of work on porting the inlet tract, and gas flowing the carb into the port. Rabid had some of the base circle from the cam removed and with grinding away the aluminium to allow the cam to rotate without clapping the casings, the engine ended up with 11.5mm inlet lift.
A central 10mm sparkplug was fitted and we blocked off the 14mm plug hole. This allowed the advance to be reduced, thereby improving performance as well.
Any engine with large advance shows the combustion chamber was poorly designed.
Spent lots of time getting the magneto timed and firing to provide maximum benefit.
A free flow exhaust was fitted with a reverse cone mega.
Plus a lot of weight saving, with all non necessary bits thrown off or replaced with lighter items.
The first time Rabid took it out in my street, he came back but not with a happy face, ‘It’s got no guts’ he said. ‘Slower than a standard bike’.
Second time he wound the throttle on a bit and the bike took off like a scalded cat once the revs built up.
The power band had moved up the RPM scale, no longer a docile plodder but a quick 500 single which was and still is an excellent cost effective bike for track use.
He can improve the bike even more with a higher compression ratio, maybe a larger carburetor, larger overlap on the cam etc. but in doing so, the engine becomes even more peaky and then you need a 5-speed close ratio box to keep the revs always in the power-band, otherwise on most tracks the bike will become slower as far as lap times are concerned!
Then its even better tyres, improve the brakes, dry clutch, it could never end?
Jumping out of gear
John B mentioned a guy, Clifford who owns C&B Gears as the person to fix this common problem.
Far far better John tells me than Neilsens and a 1-year guarantee.
C&B Gears.
14,McNaughton Road.
Illiondale.
Edenvale.
Tyre fitting.
Bit late for Zkops but there is a tyre fitment company located at Zwartkops that will change or repair a tyre for you.
Maybe when we are next at Zkops, I might be a good time to have the old tyre taken off and your new one fitted?
Cost? R85.00. Which includes removing old tyre and tube, fitting new tyre and balancing.
Have to bring wheel not the whole bike.
Zwartkops bike tyre fitment.
Tech 2.
I’ve been battling with carburetion flooding on the Triton. That’s after new Viton needles, floats, jets, gaskets and re-sleeving etc. bodies cleaned, jet drillings cleaned out, the lot.
I set those float bowls up so carefully that Barry Johnson the designer of the Concentric would be proud.
I had three separate goes at this, each time off to Midvaal to test. I was beginning to believe I should give up tuning a carburetor, but perseverance usually pays off.
Ticked over fine but once on the track the buggers were not right and I could feel the engine was running extremely rich.
Back in the pits each time, the carbs were percolating. Indicating very high fuel levels.
Then a casual remark by Clive Arrandale as he rode behind me, he mentioned my back wheel was bouncing at Midvaal.
Later that night I woke up with a start and I think I found the reason why the flooding?
The out of balance back wheel is transmitting shock into the frame and this is knocking the floats off their seats.
Next morning out with the back wheel and into the wheel jig. The wheel was all over the place and many spokes loose.
This after very careful setting up and getting everything spot-on.
So you need to let things bed down and then redo your wheels again, just in case.
Strange, I never felt a thing.
So I’ve done the wheel again and time will tell.
Thought of a way to put a rubber-mounted remote float-bowl on the Triton but I need to find a bowl off a SU from a Jag. But this is a plaster instead of fixing the original problem though.
Lastly.
We have problems when we are at certain tracks. Being pushed out of the way from the main bikes / pits, the speaker system usually doesn’t work.
So we have to keep going to and from the marshals to find out if the meeting is running late etc. Roger took the task on but it’s a lot of twoing and frowing.
So an idea came up.
Put a battery driven transmitter with microphone next to one of the circuit’s speakers and transmit it to our pits.
In the pits is a receiver connected to an amplifier.
With our own speaker we can set the sound level and now listen to what’s going on.
Should have it ready in a month or so?
A bit of fun.
I just applied for a building permit for a new house.
It was going to be 100 ft tall and 400 ft wide with 9 turrets at various heights and windows all over the place and a loud outside entertainment sound system.
It would have parking for 200 cars and I was going to paint it snot green.
The Town council told me to f... off.
So I sent in the application again, but this time I called it a Mosque.
Work starts on Monday...
Renault and Ford are working on a new small car for women.
They are mixing the Clio and the Taurus, and calling it the "Clitaurus." It comes in pink and the average male thief won't be able to find it, even if someone tells him where it is.
Mike