News 2010 - 10 Years of The Fang!

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26th July

With 'The Fang' up for sale (now on ebay), it was time for the cereal packet bike to make it's debut last Saturday, did I say it was a Honda Super Blackbird?
During the previous week I removed preload spacers someone had put under the rear shock mount, and rotated part of the suspension linkage to drop the back end down around 50mm. Sliding the fork tubes up through the yokes 25mm lowered the front a bit and made the whole bike a lot more manageable. Apart from removing mirrors and indicators that was it.
A trip to Tim Blakemore Racing confirmed that the engine was in particularly fine form with 140.3hp.

With the bike unloaded at Shakespeare County Raceway for the 'Ladies That Launch' event Bryony was beginning to get a little nervous; the jump from 46 to 140 hp and without wheelie bars was obviously going to need some care.

By the time I caught up with her in the fire up lane she was beaming and enthusing about how smooth it was, though as we neared the start she admitted to a pounding heart . I couldn't wait to get this first launch over as I was a bit nervous myself. My main worry was that she would forget the road, up for up pattern gear change and stamp into a lower gear down the track.

I needn't have worried as she took it very steady and had no problems at all, the beaming smile was even bigger when she returned! After another couple of steady passes to get a feel for the launch Bryony opened the bike up a bit and ran 13.3 at 122mph. To say she was over the moon was an understatement.

Now a quick change of number plate so brother Dominic could have a go. He is currently planning a return to drag racing, so was very keen to try something a bit more powerful than his CG125 commuter! Once again more grins as he too was very impressed with the smoothness and sheer brutal, but refined efficiency of the bike at going very fast.

Number plate swapped again and Bryony went for what turned out to be her last pass: A little quicker to half track this time, though still way off 'The Fang', but then she hurtled off to a 12.3 at 128.5mph. Sadly just as Dominic took over the rains came, and after about 30 minutes the meeting was disappointingly called for the day. It was such a shame, even more so as we had to leave early and missed the special photo shoot. We will be back next year for sure, a big thank you to all the staff at Shakespeare County Raceway who made the event possible.

Despite the limited number of runs it was a great start to working with the new bike. It is going to be a while before Bryony can get near the 1.8 second 60' times she set on the CB500T (best was 2.29). However hitting 96mph at half track is quite a consolation, especially since I told her to drive off the line like she was going to the shops!
For me it was so nice to just relax and take photos. The whole point of buying this bike is that I don't have to do anything to the engine to add performance. However there is a lot to do for next year. Priority is to remove Honda's silly CBS braking system which uses 10 brake hoses, and a lot of unnecessary gubbins like fork mounted master cylinders etc.
In the pipeline is a new custom built Turnertech exhaust system and Power Commander, these should liberate more power and dramatically reduce weight. Just removing indicators, mirrors and centre stand resulted in a loss of about 6 kg. I hope to loose another 50 kg for next season. Possibly a little optimistic, we shall see.

Bit of a change from Bryony's Hyosung GT125 road bike!

Bryony's brother Dominic returns to the drag strip after a 5 year break.

10th-12th July

For some weeks now we have been drifting along with vague plans for racing next year, somehow nothing seemed to fit together in a meaningful way. By that, I mean possible classes to run in, sponsor's interests, and my increasing lack of enthusiasm for working on the engine. I'm long sighted and find it increasingly difficult to see what I'm doing at close quarters. I also have bad eczema on one hand which doesn't respond well to oily bits of bike engine.

Besides, those who have been following these pages may remember I mentioned the 'Luddites' at the beginning of the year. Well I did a bit of thinking and realised that the Luddites were onto a looser with their anti-technology philosophy, mind you I still believe electric windows are a product of the forces of darkness.

Yes, I admit it I am a hypocrite: We have bought one of those cereal packet bikes I referred to in February. Hopefully over the next few years I can make it look more like it fell out of a bio degradable packet of organically grown, sugar free museli.

Thanks to all those people who have already contacted me regarding this web site, it will continue. More news soonish.

Shock, horror, probe!

THE FANG IS FOR SALE!

I can't believe I am doing this but it's true: Click here for the sale page.

28th June

The plan for Sunday was for Bryony's Mum Sharon to race at the VMCC sprint at nearby Wroughton prior to her Birthday the following week. During the previous 2 weeks I modified a Honda MT125 racing fairing, to make it look a little more like the 1966 RC116 50cc twin.

Not being a fan of fibreglass or paint spraying this was a pain in the bum, but by Friday it was fitted and worth the effort though it puts the old front mudguard to shame. Need something a bit more 60's, mind you I am cheating with the disc brake anyhow.

Bryony and Dominic came along on Sunday to give Mum a few tips (the cheak!) and offer moral support. Sharon hasn't raced for 15 years and not done many miles on the road since then either. So she was a little apprehensive when we rolled up at Wroughton in blazing sunshine to a pretty crowded pits.

The first problem was the bike cutting out at low revs, it eventually transpired that this was my fault; I made a new knurled adjuster for the throttle stop and forgot to reset the tickover, oops! Never mind, Sharon enjoyed playing racers with the throttle, perhaps the TT next year?

The next little niggle was the gear lever which wouldn't adjust upwards far enough (Sharon is quite a bit shorter than Bryony who I built the bike for in 2008). This caused a few problems as with the addition of the fairing the whole bike is a bit cramped.

I could tell Sharon was going to enjoy riding the bike as she went off for and exploratory blast down the pits; accompanied by an ear splitting shriek from the megaphones. The big grin upon her return confirmed this, and she was most impressed with the bike's performance.

And so it proved, despite the gear lever problems and unfamiliarity with the bike, Sharon had a great day with a 17.66 @ 78mph on her 3rd run. The bike sounded utterly glorious and plans are been laid for the next outing in August. Hopefully we can have a go at a flying 1/4 to see what the little beast will do as regards to top speed.

PS: The green number plate background (250cc) was chosen for purely aesthetic reasons.

14th June

Last week was a hectic struggle against time and annoying problems: Finally after nearly 7 weeks the crank came back, but they had forgotten to weld it and there was not enough time to fit it; words failed me, it was a bad week.

Having spent ages adjusting the Dyna S pickups precisely, to get the ignition spot on I rushed over to Tim Blakemore Racing for a dyno test, hoping that I had resolved our lack of power. Sadly as in the last test, the fueling was all over the place in the lower half of the rev range. Changing the ignition timing by 5° made no difference.

I was still concerned that my manual gives full advance at 40° yet Pazon, who supply race and road ignitions for the 450/500 twins, have 35° full advance. By all rights I should need even less with my twin spark plugs.

Tim Blakemore suggested I check the valve timing, so much of Wednesday night was spent resetting the valve timing which was indeed out. I was too tired to note by how much.
In the course of struggling with recalcitrant crank, camshafts and camchain I noticed that the wasted spark was occurring just after the inlet valve opened. I resolved to remove the 2nd magnet from the Dyna trigger rotor.

This proved to be another struggle as the magnets are very hard and I was beginning to loose my patience just a little! Eventually by machining around the magnet I was able to chip it out with an automatic centre punch.

Early Thursday morning, the camchain was finally joined and ignition timing reset yet again. Feeling moderately confident, last year's jets were refitted to the carburettors and the engine fired up. It sounded much better and more aggressive.

A new rear tyre was installed and off to Tim's again. Imagine my delight when we discovered the missing power had been restored and the fueling was very close to perfect, better still retarding the ignition to 35° gave a slight improvement.

On Saturday morning we arrived at Shakespeare County Raceway to find a radically new pit layout. Despite this, things ran very smoothly as usual, and by 11am Bryony was at the head of the fire up lane alongside a very nice gent on an HD V-Rod.
The first run was a good 14.2 with the speed back up in the 90's so very encouraging.

Back to the pits to adjust the chain, this is when near disaster struck: Setting off back for the track Bryony caught her foot under the gear lever bending it badly. I bent it back a little but was very worried about it breaking as it is aluminium.

Next run against the V-Rod again, and gear change difficulties resulted in a launch in 2nd. We resolved that I would put the bike into first after each burnout as Bryony was having difficulty getting her foot under the gear lever.

Run 3 and a missed gear change, Bryony was hopping mad!

Run 4 against the V-Rod again and this time Bryony was in determined mood and back in the 13's, at the 990' mark she was only 25 hundredth's of a second behind the V-Rod.

Run 5 and another missed gear change, aaaagh!

Run 6 and I was willing the gear change to behave and Bryony gave everything she had, the result; a new PB at 13.6! Were we happy or what?
Interestingly the 60' time was a whole 1/10 off Bryony's best, so the potential for a 13.5 is definitely there. Bryony thought the track was not quite as sticky as the last event when she was consistently in the 1.8's with less power.
Time to retire to the pits to let things cool off and celebrate with a leisurely lunch including Sharon's wonderful home made date and walnut cake. Little did we realise the track was closing at 3pm, luckily the V-Rod owner told us just in time.

A frantic dash ensued to get to the fire up lane for a final run. Bryony was lined up against a racer from many previous encounters on a Denco KH750 triple drag bike. Determined to make the most of the last run she set new best figures to half track then disaster; the bike jumped out of 4th gear and coasted across the line at 68mph. A disappointing end to the day, but we were very happy with the new Personal Best.

To finish things off, we were given permission to take some startline photos of Bryony and The Fang for the sponsor who supplied her leathers. A big thank you to all the Shakespeare County Raceway staff for their help with Bryony's drag race career, and of course for the organisation of the event.

So next weekend Bryony will return home to assist with replacing the crank and sorting the gearbox gremlins. Meanwhile I have a new and stronger gear lever to make.

Just to add to the fun, Sharon's fairing for the 125 is due this week. Good job I love motor bikes!

By chance I catch the moment the clutch bites; the forks appear to have extended just a few mm.

A fraction of a second later and the V-Rod is left behind.

Bryony's mum Sharon pulls funny faces at car drivers as Bryony dreams of more horse power.

Photo for the sponsors who supplied Bryony's cool Spyke leathers.

17th May

A sunny day beckoned on Saturday morning, so we trundled off to Shakespeare County Raceway for a day of testing. Hoping also to getting Bryony's observed runs completed so she can apply for an ACU drag licence. Fortunately the National Association of Supertwins had a round at the event, so after discussing with chairman Les Harris and ACU Event Steward Tony Smith everything was set up.

Bryony was resplendent in her new SPYKE leathers (supplied by an anonymous sponsor) and Prexport boots, good job I polished the bike last week!

The first run was a test with the bike running fine, though still a little sluggish at the top end.

Run 2 was to be an observed half pass, and as an experiment I advanced the timing a smidgen. (The brand new Honda auto advance was giving 38° at full advance despite the spec saying it should be 40°)
Bryony noticed the difference riding through the pits; it had lost the wooly feel and was much snappier, this was born out by the quickest incremental's to the 1/8 so far.

Run 3 was the full observed pass, but as Bryony moved into stage there was a minor drama as the fire marshall called me over to the bike: The outer right plug lead was hanging off! I nearly grabbed it but though better and shut the bike down before plugging it back on, then a quick sprint for the starter cart.

Despite this delay the run was Bryony's quickest ever to the 330' mark, and when shutting down she noticed popping on the over run indicating weak mixture. Sure enough after another run the plugs looked a bit pale, but I decided not to risk jetting up as time was running out. A trip to Tim Blakemore Racing will sort that out when we get the crank replaced.

This is all very encouraging as despite being down on power Bryony has continued to refine her launch technique with brilliant results. Next on her checklist is mastering near full throttle clutch less gear changes. For my part the newly installed drinks holder on the starter cart went down a storm.

Having completed her observed runs Bryony is now a fully paid up member of the National Association of Supertwins with race number STG11. Yes Top Gas!
Even though the Top Gas bikes are currently running quicker than Top Fuel, the ACU rules say Bryony cannot go straight into Top Fuel. Bryony will have to complete 3 events before she can do another set of observed runs to ride in Top Fuel.
This got me thinking, and I have come up with a cunning plan to get a bit more performance from the bike on petrol, maybe....

Thanks to all the staff at Shakespeare County Raceway and to the Supertwin folks who made Bryony so welcome. Her first event will be the Shakespeare County Open Sport Nationals on the weekend of 28-30th August.

Mum Sharon records more smoke for posterity.

A startline delay resulted in a cold tyre and some slightly sideways action from Bryony and The 'Fang'.

13th May

Sadly the spare crank is not back from Piston Broke Engineering yet, so we will be back to Shakespeare County Raceway with a twisted crank again this weekend. Consequently we have decided to do Bryony's observed runs so she can apply for her ACU Licence.

Meanwhile back in the workshop preparation of the CB125T is progressing. I decided to replace the CB points ignition with a Dyna S trigger as we were experiencing a misfire over 12,000 rpm. As Dynatek don't supply a unit for the CB125T, I scanned the ones available for Hondas. The CB750 version looked to have the same size back plate as the 125, so I took a chance and ordered one from Tim Blakemore Racing

The back plate indeed proved to be the same size and went straight in after increasing the length of the mounting slots, so that the timing mark viewing slot was in the correct place. I also had to mill a new pair of slots in the rotor at 60° to the existing ones. This was necessary to get the magnet on the rotor in the correct orientation to the pickups. Wiring is a piece of cake and before long it was all timed up and ready to go, dyno test soon and first runs for Sharon next month.

Unlike the GL1000 Dyna S I used on the The Fang, the CB750 one only has one magnet as it runs at engine speed. I may get one of these for The Fang so that the system does not have a wasted spark, as this should be better for the blown/methanol setup.

More news soon pending good weather this weekend.

The CB750 Dyna S fits neatly in the CB125T engine cover. Yellow spot and arrow for advance are aids to track side timing adjustments.

19th April

With the weather finally improved sufficiently for me to spend some time in the workshop, I stripped the engine and discovered a huge score in the left liner. I had a spare, so this was fitted and re bored to suit with a new set of rings. The engine seemed fine apart from that and spotlessly clean inside, oil changes after every meeting make sure of that. I reground the valve seats a little just to clean up a few faint pits, and was fascinated to see that the backs of the exhaust valves were eroded by the acids from our blown/methanol dyno runs.

With the engine rebuilt and mechanical advance unit modified with a 2nd keyway as mentioned in my previous post, I spent ages setting the ignition timing spot on. It was at this point that I discovered the right piston was now 55°, not 60° in advance of the left. The crank must have twisted during the supercharged dyno runs, oh dear.
There was no time to strip the engine again as I needed to get the bike on the dyno before heading for Shakespeare County Raceway on the 17th April.

The dyno test at Tim Blakemore Racing was another surprise; carburation all over the place and 6hp down. Aaaagh! Tim set the carbs up so we could at least run the bike, as Bryony was champing at the bit to get back on the track. But it was a big disappointment after all the engine work and our new Dyna ignition.

Still, as we headed for SCR on Saturday morning at least the sky was crystal clear, with of course no con trails due to the Icelandic eruption.
The new road surface at SCR is nothing short of wonderful, well done guys. We were soon scrutineered, signed on and heading down the fire up lane with a bunch of riders on Suzuki Bandits and a couple of Fireblades.

Bryony was a bit nervous wondering if she would have forgotten how to do a burnout since September. She needn't have worried as a great burnout was followed by a dynamic launch against a 600 Bandit. The old 'Fang' fairly leapt off the line then wobbled violently at the 60' mark. Bryony almost kept her advantage to the stripe, being pipped at the post by a mere 0.22 seconds. The missing horsepower certainly made itself felt though, as we were 6mph down on speed and 0.4 seconds off on the ET. But the 60 ft was our best ever at 1.878, Bryony grinned from ear to ear, what a great way too start the year. The rest of the day followed in similar vein with a string of 1.8's, although between 1-3 pm the heat was unbearable and we had to retire to the pits for regular bike cooling sessions.

All in all a very satisfying day at the 1st Volcanic Ash Nationals (very funny, guys), during which the other winter tuning item (cable tidy on the starter cart) performed faultlessly. In view of this success a drinks holder is now planned and Bryony's request for seat padding on the bike is under review.

So the next few weeks will see a crank rephased and the engine rebuilt again, we might even find the missing 6hp!

Above: Dave Derry photo

22nd February

SOMETHING of a milestone has been reached: The Fang's 10th anniversary, will it finally fulfil its promise this year?
Am I really mad to pursue this crazy project for 10 years?
Is it just me that thinks most modern bikes look as though they fell out of a cereal packet?
I suspect I have finally become a Luddite. Ownership of a Royal Enfield obviously confirms this, yet I feel strangely content. More philosophy to follow next year, or maybe not. Meanwhile back in the shed:

DUE to the awful winter I haven't been able to summon much enthusiasm for heading out to the workshop, so things are a bit behind schedule (as in shed not sked whatever that is).

Having drained the oil after our last supercharged dyno runs, I was rather alarmed to see a small amount of steel swarf in the sump bung. On the positive side the oil was not visibly contaminated with methanol as it had been in the past, ergo we must be burning all the fuel for once.

Compression is low on the left cylinder so a major strip is in order, but before this I recently got around to making an outrigger bearing to support the gearbox layshaft.
Doing this would require a new design of sprocket with extended splined boss, and initially I planned to carve one from solid. Then I thought sod it, life is too short, and bored out a sprocket then welded it to a new boss. An aluminium housing was then made to suit a substantial bearing, and bolted to the back of the sprocket cover.
Having transferred the stress from the layshaft to the cover, I then carved an aluminium bracket to connect the cover to the chassis via a couple of welded on stubs. This bracket is the one above the gear linkage rod in the photo on the right, you can just see the bearing housing to the left of the sprocket.

It's been quite a bit of work, but with 36 rear wheel horse power at only 2,500rpm (standard bike is 8!) and over 70ft/lbs of maximum torque, not before time methinks.

Jobs to do besides general engine refurbishing include modifying the advance/retard unit so I can rotate the ignition pickups 90º. This will allow correct setting of the air gap and clear access to backplate securing screws.
The plan for this year is to run the bike on carburettors again first to ease Bryony back into things. Then hopefully get the blown configuration running properly on the dyno, before a full supercharged blast down the track at last.

We would like to thank all those who nominated and voted for Bryony in the 2009 Sportswoman of the year category at Shakespeare County Raceway. She may not have won, but it has certainly given her a confidence boost, and may have swung a sponsorship deal; more later.

Finally for the moment, Bryony's Mum has decided to take to the track again for the first time in 17 years, so I have to dust off and refresh the CB125T as well. A fairing will be added too, so expect big things from Sharon!