Racing Update - BHR Mallory 15/4/12

After a 20 year layoff from competitive road racing (and I use the term 'competitive' in the loosest possible terms), I squeezed my fat arse back into leathers earlier this year, and entered for the VMCC Britsh Historic Racing (BHR) season opener Mallory meeting on Sunday 15th April.

Up until this year I had been reserving my track time each year to the odd Twisty Sprint and Race Demo meetings - such as 1000 Bike Festival and occasional Brooklands meetings. Although I enjoy these meetings, I was beginning to feel a bit of a fraud, and was also thinking it is was probably not much more dangerous to do a proper race meeting, than doing demo's. Like many that go racing, 20 years ago I gave up when I got married, had kids, responsibilities etc, but I figured, if I am going to do it again before I get too old and decrepid, then I ought to do it soon!

It was great to be back racing (of sorts) again, and really nice to talk to some of the old faces still racing - like Ian Bain, Merv Stratford, Norman Lawton and my old mate Brian Hunt - who I remember started racing at a similar time to me, both with our fathers with us (and now both sadly passed away) and both on pushrod Nortons, back in the early 1980's. Unlike me, Brian never stopped racing and is still going strong - and fast , on his BSA triple.

It was a very cold day (should have worn my thermals under my leathers - which I reminded myself, as it started to sleet just before my first race!), but with good mates Manuel Hughes (ex VMCC Grasstrack Champion) and Ric Anthony giving me moral support, along with Ric's partner Erica all there as pit team we had a great day.

The Norton was still not at its best, but with a great tip from Ian (Bain) after some issues in practice it was running much better in time for the first race. Being very out of practice, I got left at the start (and made a mental note that new clutch plates are called for - Brackley last year must have finished them off!), but after an enjoyable race I managed a 5th place - albeit a long way behind Bain/Cramp/ Farrell in the top three who were all really flying.

Unfortunately that is where the fun ended, because having got the racing juices back flowing, the Norton expired on the warm up lap to the second race - but never mind, overall a good day had by all, and although I dont intend to be a regular, I do fancy doing the odd meeting again - probably Cadwell next in the final meeting at the end of September

Mallory BHR - Exiting Edwina's in Pre-48 Race 1

See video on YouTube

If you would like a laugh - we took some video footage of the day at Mallory, so press on the picture below to take you to the YouTube link where it is uploaded to.
As well as footage of the first Pre-48 race - the race I was in, there is footage of one of the main Pre-58 races and also some good sidecar and 3 wheeler footage.
The CS1 Norton that you can see in the first couple of minutes of footage is the super fast example owned by Ian Bain. Ian is an extremely talented rider - but that bike is pretty special as well, and I think may be an Ex-Works bike.
Apologies for the loud introduction, it was my first amateurish attempts at using new video streaming software, but I shall be doing more video streaming in the near future, so hopefully they will get better!:

Click on Picture above to go to YouTube

Mallory VMCC Practice Day - wearing No 8.
Velo mounted Phil Cramp on far right looking down

Martin (who does the mail order side of the business) and myself chatting between stripdowns!

Always fun circulating with bikes of different size and ages in the open practice sessions - most of them had better brakes than mine!

VMCC Practice Day Blues

I had done the VMCC mid-week practice day a couple of weeks before the actual race day, but things had not gone as well as expected. I had been struggling with overheating issues on the 38 Racing Inter for the last couple of seasons, but because I was only doing the odd short sprint or demo on this bike, it had not been much of an issue.
That does not mean I had not tried to find the problem though, I had stripped and replaced almost everything North of the crankcase in an effort to find the cause – i.e 3 different carburettors, 2 cambox’s (although I wanted to fit a magnesium cambox rather than the original aluminium one anyway), different cams, different valves and guides, different magnetos etc).
Although most of these had resulted in minor improvements (and is part of fettling any race bike), I had still not got to the root of the overheating issue, which seemed to manifest itself after about 3 laps, and resulted in revs dropping off and a strange squeaking developing from the top half of the engine (which I thought at first was inlet valve, but later I think turned out to be the top piston ring area starting to just nip in the bore). The jetting was massive – even for methanol, but only looked at best marginal – i.e. a light brown, rather than deep ebony which I would have preferred . . . but even going up to 1900 main jet with 120 pilot, the colour was not changing – which gave me the (false as it later turned out) impression that it was not jetting that was at fault.

Anyway, by the end of last year, having exhausted all normal avenues, I got to thinking that maybe the head porting was a bit too radical, and had lost its venturi effect (it had had lots of previous surgery and was running a very large inlet valve and 1.250” tract. Luckily, at the end of the previous season I had spoken to a friend of a friend and been very fortunate to have been offered a very nice all alloy round International cylinder head for a reasonable sum of money, which I had built up with standard (large) valves and my own valve gear – including titanium collet cups.
This was fitted and ran for the first time at the practice day, and I felt quite confident, having ran it the previous day at home and thinking how crisp it sounded. Four laps of a dry Mallory track was all it took to tell me that, alas, this was not to be - the engine was still overheating and sounded no better - bugger!.
A day of constant minor strip downs and adjustments (including resetting ignition timing) between sessions did nothing to clarify the picture and therefore I was left no option but to strip the engine down again once home. I found a few minor things amiss (including a cracked carb mount), but the only real area of concern was the piston had a strange shiny wear mark around the top ring, which led me to think that just maybe this may be nipping up when hot. Although I was not convinced, I had ran out of other ideas - therefore I swapped from the American Arias piston I had been using since I first built the engine, to a much lighter UK made Omega dope piston from Stu Rogers (I don’t stock dope pistons myself, these give approx. 13:1). It was with this configuration that we went to the Mallory race with – with fingers crossed!

The first (very cold) practice, demonstrated that instead of making things better - if anything it seemed worse!, with revs dropping right off going round the very long righthander at Gerrards. Having come in at the end of practice, frankly I was feeling very pissed off and had ran out of ideas! Everything seemed spot on mechanically – yet it was running like a dog. It was at this point that I took a walk over to see Ian Bain opposite us, who kindly came over to have a look, and immediately spotted what could be the cause – Amal TT needle too thick! It turned out that a few years ago Ian had had a similar problem with his bike and with help from Merv Stratford had found a similar problem, i.e. the thickness of the standard TT needle, even with the throttle fully open, was actually resulting in a smaller opening at this point than the main jet further down – which would explain why in my case changing the main jet was having absolutely no effect whatsoever!
To resolve his problems at the time, Ian had managed to get hold of a special type of TT needle which was ultra thin. However, I did not have one of these (I am embarrassed to confess, after 25 years of fitting TT carbs to various bikes, many running on methanol, I did not know that such a thing even existed, just goes to show!) but rummaging through my spares tin, I did find another TT needle a couple of mm shorter than standard with an extra notch. I fitted this on the highest notch – so the needle taper would sit as high as possible and lined up for the first race (half expecting to be pulling in after two laps).

What a revelation!, I think we have found the Silver Bullet! Although still not perfect, the bike was transformed. It was now pulling much cleaner at high revs and after two laps did not feel any different whatsoever, with no signs of the overheating issues that had plagued it before. As I mentioned, after a fun race I managed to blag a 5th place and felt much happier about the bikes potential for the future. Still not perfect, but definitely a big step in the right direction – and definitely the mystery cure of all the problems I have been having – I am just a bit embarrassed I did not think of it myself. Now I look back, I think that when I was swapping TT carbs, I was leaving the TT needle in place – as I mistakenly believed this was the only needle type available for a TT carb.
Unfortunately the bike expired with a none related issue at the start of the second race, but is now rebuilt and I have managed to get hold of one of those special extra thin TT needles – so am expecting an even better running engine in its next meeting. I was hoping to have put the bike on the Dyno before now – but with the pressures of the Norton parts business, and the day job, this has not been possible – but all being well we will give it another go at Cadwell and see how it goes. Big thank you to Ian Bain though, good spot!

Arias Piston

Arias piston with top ring removed - note unusual shiny rub mark around ring land, indicating where it may have been nipping up when hot

Omega vs Arias

Interesting comparison - UK Omega dope piston on left vs Arias dope piston on right. Both forged, but Arias much heavier

Omega being fitted

Omega piston being fitted - barrel spigot also had to be shortened as part of this process, but also earlier as part of changing heads (pre-war bronze skull, changed to post war full alloy) - but that is another story!

Dope Needle
Since the mallory race I have managed to get hold of a special Amal TT 'Dope needle', shown at the top of this photo. As a comparison, the needle at the bottom is a standard Amal TT needle, notice the big difference in taper for the last one inch of the needle (i.e. full throttle). Email if you are interested - I may have a batch made