SpeedwayBikes.Com
USA Speedway  

Stan Bradbury's Speedway Training Notes


Table of Contents


 

Speedway Training Notes
by Stan Bradbury


PREFACE

Extract from "Book of Speedway Notes"

How to Get Started in Speedway


So you've seen enough of motorcycle speedway racing to make you keen to give it a try, you are either fit and young enough to recover quickly from any physical injury you are likely to receive, or experienced in taking spills via motocross, dirt track, etc.

At the time of writing, the best machine (indeed, the only practical machine for a newcomer) is the 2 valve Jawa, by far the most durable and forgiving speedway machine ever to be sold. The value of such machines at this time is from $700.00 to say $1200.00. These prices could include some of the necessary spare parts such as a selection of engine and rear wheel sprockets, maybe a spare rear wheel, etc. Unfortunately, the J2V is slowly disappearing and becoming a collector's item, so, a J4V DOHC or SOHC is the next best alternative. The Weslake engine is too fragile to give long, trouble free service and the GR and GM too rare and expensive, etc., at time of writing.

Make sure the machine can be started, and runs without any excessive mechanical noise. As stated elsewhere in these notes, the heart of the Jawa 2V is the big end bearing (also called rod bearing, crank bearing, etc.). If the last owner can not tell you when it was last replaced, figure on replacing it immediately. The only two other components on a Jawa 2V which can wreck your engine are: an old and/or defective exhaust valve and work stressed valve spring caps (light alloy). By replacing these parts, you are almost certainly eliminating self destruction, leaving you with only a rather uncertain ignition system, if original, to repair simply, permanently and efficiently at low cost, if it should ever give trouble.

One advantage of a Jawa 2V is that you can step up to more competitive machinery, if you wish, once you are experienced enough to handle the extra power. A Weslake or Jawa 4V DOHC with side-entry carb. can be bolted straight into your present machine, with only such additions as an exhaust pipe (and an ignition system, if you choose a Weslake or a Godden GR). Another alternative is to install a centre-port engine along with a centre-point frame "diamond" (or the front part of the frame). This will again increase the cost slightly, but you could finish up with a machine comparable with the best equipment presently available.

At time of writing, the Jawa 4V SOHC engine was not available with side-entry carb. It was found that the Godden GR50O could be adapted to side-entry carb., as could the Jawa 4V DOHC.

Having acquired a machine, the next step is riding equipment. Very often, this can be borrowed in whole or in part until such time as good used or new equipment can be purchased. To go racing at a sanctioned event in Canada it is necessary to use the current Snell approved helmet while, for unofficial practise, the previous Snell-approved type can be used, although not recommended. For CMA events full leathers, boots and gloves must also be worn and for unofficial practise, it is wise to stay with those same requirements. A steel shoe is of course, as essential as a bike or a helmet. This can be a make-shift affair for practise, but any steel shoe which is in danger of breaking up at a CMA event will not satisfy the referee's inspection. Steel shoes can be purchased to fit any of the more recent lightweight, reinforced boots designed specifically for speedway. Motocross and construction boots will require a steel shoe to-be made up to fit the actual boot. At time of writing, the price for custom steel shoes varies from as low as $75.00 Canadian to a high of about $145.00 Canadian, if purchased abroad and brought into the country through normal channels, after shipping, duty and taxes (and brokers fees, if any), have been added.

So now you are all set to go for practise. Be sure you have a stand for the bike if you intend to warm it up properly before riding it (the machine can be leaned over on its footrest for a while but this tends to cause flooding of the carburetor). As a lot of practise takes place in the colder weather, provide some sort of cover for the engine after warm-up and between practise sessions. Tools, spare spark plugs, fuel and oil of a suitable grade for the time, of year should also be carried. Also plan on covering the machines vital parts with plastic or etc. to keep out rain water if you are going to be transporting the bike to the track on a trailer or open pick-up.

Okay, so we are on the road, now, where do we go? Again at time of writing, there are several places where practise can take place. Call your friendly CSRA representative for the location nearest you. Maybe you live too far for anything but occasional visits to an organized practise track. Good practise can be obtained on smooth grass, smooth lower levels of disused gravel pits or, on frozen ponds or lakes using sheet metal screw heads as studs, providing the cold weather problems outlined in this book are taken care of While none of these alternatives are ideal, they will permit you to become familiar with the machine and increase your confidence.

As specific riding tips are outlined in a separate chapter, they win not be repeated here instead, I will try to outline some of the problems of buying a used machine.

Inspect the crankcase on the drive side for signs of the case having been welded. Jawa 2V crankcases are, one of the parts which are no longer obtainable new, and the drive side case is a frequent victim of a bad big end failure and tight, or seized primary chains (more about, chains later). Consequently, welded crankcases should reduce the selling price of the machine although, if properly welded by an experienced welder, the cases could be as strong, if not stronger than new. As stated earlier, make sure the machine can be started reasonably easily by an expert and that the engine runs well. Take a look at the visible ends of the fibre clutch disc dogs and satisfy yourself that there is no more than one or two missing, otherwise you will need to replace some or all with new or used fibre clutch plates. Make sure the clutch and throttle cables are not kinked where they enter their respective controls. Check all the spokes are there, and spin the wheels to check that the rims run reasonably true. Don't worry too much about tires as these are considered expendable. If you are getting good tires, that's a bonus. Examine the frame, forks, and rear stays for cracks or obvious signs of major repairs. Remove the oil filter cap and check if the frame is cracked across the oil fill hole or if it has been re-enforced with bronze welding. These indicate heavy crashes and in the case of the re-enforcing, major repairs. Stand in front, then behind the machine with the wheels in line and see if you can spot any frame misalignment. You can even go through the alignment checking procedure outlined in the book, if you have the opportunity. Also, sight down the rear chain from behind the machine and see if the. rear wheel and countershaft (jackshaft) sprockets appear to be in line. Check for play in the wheel bearings and countershaft bearings, also for back and forward movement in the headstock.

Also check the clearance in the fork leg bearings by wheeling the bike back against compression and then forcing the front wheel back and forwards while gripping it at top centre. If the fork gaiters (or boots) prevent you from seeing any play, squeeze the plastic boots in until you can feel where the forks legs enter the bushings in the fork "H" section. Check that the alloy engine plates are okay, no cracks or welds or elongated bolt holes. Check that the exhaust pipe is not flattened on the under side parallel to the ground. On the Jawa 2V, check the condition of the exhaust flange where it threads into the head. If this has come loose a few times or has been forced in on a "Crossed" thread it may have stripped the rather fragile threads in the alloy cylinder head exhaust port. Expensive, oversize exhaust nuts are available and also a conversion to the Jawa 4V pipe is possible. Check also the condition of the spark plug threads in the cylinder head and while you have the plug out, check what the top of the piston looks like. Look out for a dent in the top of the piston which indicates that someone has used the wrong long reach plug with an external electrode instead of the correct long reach plug with a recessed electrode. Again, damaged plug threads can be repaired by having a thread insert fitted, but all these little things cost money.

None of the foregoing would be sufficient to deter a person from buying such a machine as long as the cost of such repairs are taken into account.

Very often, novice riders are inclined to get sidetracked into such things as machine appearance and "how to make it go faster." This is an unfortunate tendency probably developed from the necessity of such action when modifying standard road motorcycles for racing purposes.

The speedway machine is a thoroughbred and, apart from ensuring that it is in first class order, any so-called tuning will only make the machine less reliable. There is much more than enough power in a standard Jawa 2 Valve engine for any rider until he reaches expert status (providing the engine is operating as it should and the rider is going as fast as the machine will carry him). The more powerful 4 valve machines require an experienced rider to put that extra power to use by getting more traction where and when required, by "scrubbing off" no more speed than necessary when entering the turns and by balancing the machine between spin and lift of the front wheel at the start.

Everyone prefers to have a smart looking machine but a new rider on a low budget should concentrate on keeping his machine clean and in good running order before having expensive paint jobs, exotic fiberglass etc. Expensive chrome plating of frame, forks, rear stays etc. may look good but it causes embrittlement of the tubing and, if any straightening of these parts is required, it is usually necessary to grind off the chrome. If cost is no object then of course, that changes the situation although nickel plating is much more satisfactory for metallurgical reasons than chrome plating. New riders should bear in mind that if they are going to practise on dirty tracks for a while before actually racing, the machine appearance will probably deteriorate quite rapidly. Once confident and fairly accomplished, the rider can then "dress up" his machine for display in front of spectators at a race meeting with less chance of its appearance being damaged. A great deal can be achieved with hi-heat aluminum paint over-sprayed with clear polyurethane lacquer plus a few well chosen accessories such as polished aluminum fuel tank, etc.

There is a vast selection of custom components now available for such "dressing up" with the advantage of being durable and designed specifically for speedway use with fibre glass designs being part of the fibre glass itself, rather than surface painting. While first cost may be higher than "do-it-yourself" painting, its durability would prove its value. Chrome steel wheel rims and chrome steel handlebars are also more durable than the much lighter alloy rims and bars as are the metal or plastic fenders as opposed to fibre glass. Unfortunately the chrome steel 23" front rim and speedway pattern chrome steel bars are disappearing and are already as high, if not higher in price than the more popular light alloy. Alloy handlebars require special mounting clamps, and must be replaced if bent to a point where they require straightening, because of crystallization which always occurs in the bend area.

Frames and forks are the most vulnerable parts when the inevitable spills occur and it is a good idea to make up a plywood template of a straight frame diamond to check against your suspect frame diamond, whenever it is subjected to a heavy spin. Two straight edges, one across the top front of the fork "H" section and the second across the bottom front (where the fork legs or fork sliders enter) will, if viewed from above, indicate how much the "H" section is twisted. If the fork legs still move up and down against their springs, they cannot be bent very much. If they are jammed, it only takes a few minutes to remove the fork legs and lay a straight edge against them to see how badly they are bent. The rear frame loop is very robust and seldom needs attention unless involved in a very heavy crash, at which time it requires checking in a jig or against a known-to-be straight rear frame loop, with professional repairs, if required.

So, you are all set, you have a machine and riding equipment and you have somewhere to ride. You also know enough about the machine and riding technique to know what is required, after reading these notes carefully. Good luck.


<--  Previous Page  ---  Next Page  -->

Copyright Notice

 

www.speedwaybikes.com - All rights reserved.