TECHNICAL NOTES FOR THOSE PREPARING FOR THE 2012 MANX GRAND PRIX
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TECHNICAL NOTES FOR THOSE PREPARING FOR THE 2012 MANX GRAND PRIX
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Chief Technical Officer Jeff Kirby:

I would like to take this opportunity to help everyone (riders, mechanics and technical officials) to get through the two weeks with the minimum amount of problems by letting everyone know what we expect in terms of machine preparation at the Manx Grand Prix. Some of the requirements may appear to be idiosyncratic but I can assure you that every regulation that we work to has a reason based on many years experience of checking racing machines used on the Mountain Course. I know that many of our regulations are not a requirement on short circuits but anyone who races here regularly will tell you that the long, high speed sections will give problems that will not show up in a full season of short circuit racing.

1) Although it is a FIM and ACU requirement to have the split in the front brake lines at the lower fork clamp, we occasionally get a machine with the one brake line looping over the mudguard. There are people in the paddock who can change brake lines in half an hour and you will not miss any practice.

2) Brake callipers that have a brake pad pin held in by an R-clip (eg Brembo) then the end of the R-clip should have lockwire on the open end to stop it coming out. It has happened and the brake pads fell out! It is recommended that calliper bolts are lockwired. They have been known to come loose.

3) Tyres must be correctly fitted according to the rotation arrows.

4) Short valve stems are a must. The long rubber stems that are used on car wheels will deflect quite appreciably and must be changed. Long metal stems are acceptable.

5) Metal valve caps must be fitted. The valve core can lift off its seat on long, fast stretches and the rubber seal in the cap provides additional sealing against pressure loss. Please do not use the extractor type with the slot in the top as, should this come off, it could go through the tyre of the rider behind you. We normally have a supply of suitable valve caps in the bay to replace plastic ones.

6) Wheel spindle nuts and wheel spindles must be lockwired. There was a case at last year’s TT where a front spindle nut worked loose. Where the spindle is flush with the fork legs, lockwiring both pinch bolts on both fork legs is acceptable. Rear wheel spindles that are captive at one end do not require lockwire but the nut does. Spindles using a castellated nut and an R-clip must have lockwire or a cable tie on the open end of the R-clip to secure it.

7) Exhaust springs must be lockwired in such a way so that if the spring breaks, it is retained on the machine and does not go on to the road where it could be a problem for following riders.

8) From 2010, oil containment has been required at all times on all four stroke machines so please keep a very close eye on the belly pan which should be solid without drain holes. Any holes must be repaired with fibreglass before the machine is allowed into parc ferme. Duct tape or silicone is not an acceptable repair. Unfaired machines must be fitted with a reservoir beneath the engine and the front lip must extend upwards to within 50 mm of the cylinder barrel to guide any oil down into the reservoir in the event of engine failure.

9) The lower chainguard (or shark fin) must cover the point at which the chain runs on to rear sprocket. Moving the rear wheel back as far as possible to lengthen the wheelbase and the smaller sprocket used for TT course gearing means that the guard that is OK on short circuits will be a long way from a position where it is effective.

10) Numbers and backgrounds will no longer be supplied by the MMCC. The font used for the numbers should be as plain as possible so the marshals, spotters and timekeepers can readily identify the machines as they pass at high speed. Painted backgrounds are acceptable providing that matt paint is used. Putting the background inside the screen and the numbers on the outside is not acceptable. Shiny backgrounds and a low sun make a bike coming down Glencrutchery Road look like it has a headlamp on! If it is not possible to put the number in the centre of the fairing then it should be on the right hand side when sitting on the machine. Side numbers can be on the fairing or belly pan if the seat unit is too small. Any numbers or backgrounds that are not acceptable will have to be replaced.

11) All riders are asked to pass through the bay before going out to practice. This is so we can check that identity discs are being worn and the correct helmet sticker is in place.

12) Metal toe or knee sliders are not allowed and anyone using them will be told to take them off. This is an ACU regulation and it will be enforced.

These are the most common problems that we have encountered over the years and if you are fortunate enough to have someone else wielding the spanners, please make them aware of the requirements.

One final point, random breath tests will be carried out throughout practice and race weeks. The permitted level of alcohol is 0.1g/L.

If you have any comments or questions, I can be contacted through the Race Office.

Finally, I wish you all a safe and successful Manx Grand Prix.

Jeff Kirby
23-06-2012, 03:05 PM
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