Poco a Poco...

So now we have a rear master cylinder, and some exhaust brackets. Every day she grows a little more!

And I know the exhausts look a bit daft from the back, but at this rate there wont be anyone behind me to see them...

Am not sure whether to take a front disk off, or add a second caliper. Either way, not a massive job, I am sure testing will sort that one out!

And once I get a few little fiddly jobs out of the way I'll have to get wiring in the Silent Hektik ignition system. Oh...! And that reminds me, we'll need to make a battery tray too!

Slow but Steady...

...kind of sums up Team Thumper I suppose!

A bit of a progress report on the current state of play:

Today I fibreglassed the necessary fixings and exhaust brackets onto the tail unit; you can see the standard of workmanship here...!

I also got a (barely) functional rearset linkage on the go, to at least allow me to knock it into gear when the time comes to try to run it.

On top of that, we now have a chain (to facilitate the same), and I've cleaned up the front fairing bracket to allow a bit of welding to be done.

But its almost a bike now: the tail unit is ready to go, and the brackets for the little ally tank have been bodged out of some flattened tube. I have the distinct feeling that when it comes to actually running (reliably), then they'll have to be re-made, but they'll do for just now. She is beautifully narrow across the waist tho; we have faith in the belief that when she runs, she should be a good 'un. Getting to that point has just been more problematic (for oafs like us) than we'd ever though would be the case...

Slightly more problematic may be mounting the rear master cylinder as space would appear to be rather tight. Nice rearsets tho, eh??

Note the lower bolt in this pic (there are 4 in total) which support the seat unit and rider's weight; impressive given the lack of subframe.

Oil lines should be on within a week. Ditto the front brake line. Then after a bit of wiring, and finding a clutch lever and handlebar bracket, I would hope that we can start to think about fuelling up and putting some oil in... then Boyd can break a sweat pushing me and a dead bike up and down the street!!

Progress!

3 sets of valve stem seals, 2 camshafts, lots of thinking and stupid questions, long hours filing collets and a complete lack of any engineering prowess.

The motor is now in the frame and all the major bits are hanging on it. It even rolls... Oil lines have been problematic, tho Ben at Pirtek at Kings X has been trying hard to sort out the niggles.

I have a chain on its way, an immediate problem is the shift linkage. I have RH thread rose joints (M6 thread and 6mm pivot hole), and some M6 bar which will do for a link rod just now. However, all of the gear shaft clamps I have have old knackered rose joints (with LH threads) pressed in... And they wont press out. I need a clamp to bite onto the gear shift splines, with no rose joint on it...

Back the the Electronic Bay. Do such items exist? I'm about to find out...

Piccies soon!

a

Terrible Headaches!

Here’s a bit of an update after a rather prolonged silence. Rest assured that while we’ve been a little lax in updating the blog since Snetterton, things are progressing. As usual there’s been more thinking than actually doing!!

Oil lines should be on their way from the friendly and helpful guys at Pirtek at Kings Cross (cam feed and main tank-motor and motor-tank oil lines). They’re also fixing me up with a front brake line. However, inside the motor, I’m still fretting about the valve gear, and we are acutely aware that time is marching on. Having received the oversize shims from Rog Key, I re-checked the spring installed height; they’re all now spot-on. However, I then wanted to just make sure that the collets weren’t going to do anything comical with the valve stem seals at full lift.


The subject of much domestic strife….!

The valve guides have already been shortened for use with the Stage 4 Megacycle cam, and the motor apparently ran very well. It may have broken the bottom end, but the top was fine!

However, the pattern valve stem seals I received were not a particularly good fit. At full valve lift (measured rather inaccurately at 12.1mm for the inlets and 11.4mm exhaust) there was indeed contact. I only tried it on one inlet valve, but turning the cam by hand was enough to feel contact. I tried to get the seals to sit a bit further down the guide but to no avail. They may have been cheap, but I can hear my old man warning me “Buy cheap, Pay dear”. Paying dear would almost certainly result from a dropped valve. I resent the time and hassle more than anything: rockerbox on, rockebox off, cam in, cam out, setting/checking the tappets every time. Measure, turn, check lift, blah blah blah! So now you see why the blog’s not been updated?? This part is just too boring, and time consuming!

A second old adage of my father’s is “Buy cheap, Buy twice”. Another accurate observation from the old felly. I duly received my new Yamaha valve stem seals Fowlers on next day delivery, having placed an order at 4-30 the previous afternoon. Top service. I was pleased to find that as a result of their better fit, there was now clearance. Not as much as I’d like admittedly, but there is clearance. And the new collets are no bigger than the old ones, so I’ll probably go with it as is. Unless of course I could remove just the slightest amount of metal from the bottom of the collets…? Hmmmm, probably not.

As a little aside, measuring lift accurately is difficult as I am not, by any stretch of the imagination, an engineer. Working with a only vernier (“very-near”) caliper is difficult in the confined space of the head. And the curves of the valves and inside the combustion chamber make it hard from that side.

So having previously made a note of the lift, I then built up the collets and retainer without the springs. You can see this here, and underneath the R/D bottom cup is Rog’s shim.


So how to measure? I ended up bodging on a bit of plasticine, removing it and measuring the distance between the top of the seal and the bottom of the collets.



Obviously not the most accurate, but just about the only way I could think of doing it. And I think it will do, in the absence of any other expertise…! Or am I just showing myself to be a fool, who can’t build an engine? Well, you can all say “I told you so” when it drops a valve!

Right. Lets get this head on!

Irritating Minutiae?

Or important details?!

Since our outing at Snetterton, some things have happened...

1) My missus finally hit the roof with the prolonged head-build on the dining room table. Much cooking and grovelling to be done this evening.
2) I have dremelled the inlet manifolds such that they line up with the (enlarged?) inlet tracts in the head
3) I received from Rog (you lovely, lovely man!) some shims of 1.6 - 2.0mm to sit under the lower cups under the valve springs. These allow the installed height to be as per the R/D spec. Effectively this preloads the valve springs. I'd think that failure to appreciate/rectify this would result in valve float at high revs.
4) Ordered some spangly new oil lines.

So last night (having promised that the head would be off the table and atop the motor that evening) I got my shims on, and just before putting the springs & collets etc together, I thought I'd make sure that at full lift the collets & top spring retainer don't foul the valve guide seal.

Guess what?? There's contact... I can still turn the cam, but I wanted about 1mm clearance. The spec sheet recommends 50 thou, but I reckon 40 would do. Anyway, its a no go.

I tried tapping the seals on, taking them off, grease on the guide, etc etc. No f'cking joy. This would surely be asking to drop a valve...

The seals are pattern parts. I have now ordered genuine Yamaha parts, so we'll see if these are any neater... Failing that, it will mean (god no!) machining the already shortened guides.

Its a puzzle, as the motor ran with this cam. Although not these springs collets and retainers... I tell you what, building this motor is fast becoming a pain!

andy

SuperMono Championship (Rounds 1 & 2 - Snetterton)

Friday 11 - Sunday 13 April 2008

Friday practice was the low point of an otherwise brilliant weekend. Having been fairly confident that Steve Lakes bike, TZR250 chassis and SRX640 engine, would be reliable for the whole weekend Andy promptly dumped it at Russell’s chicane. I think he had a genuine excuse as the tyres were not brilliant (road-biased), it was on the first lap (cold tyres) and although not actually raining, it was damp. Andy suffered minor, but I expect painful, injuries – hip and hands bearing the brunt of the impact. Unfortunately his long serving Arai splat-hat also took quite a battering as he slid face down along the track.

Having walked from the pit-lane over to the scene-of-the-crime, thinking that Andy might need a hand pushing the bike back to our camp, I saw him being whisked off towards the scrutineers shed. This walk across the Snetterton paddock was to be another feature of the weekend. When I finally got there the hobbling Andy and myself were directed towards the Senior Scrutineer as he wanted “to have a word with us”. He then produced a pink sheet that listed all the following faults likely to keep us off the grid the following day (this was in addition to what they might find during the real scrutineering – Merde!). Both fuel and oil tank (Monza) caps needed wire locking shut, steering lock was too limited, no lower rear chain guard, fairing oil trap too small, and a few other minor problems! It took us several hours to rectify all the problems as best we could, and we were still not certain that the bike would still be eligible. We also replaced the broken kill switch, which was to cause much grief later on.

Saturday morning was bright and breezy as we pushed the re-built bike to scrutineering. Much to our surprise the very helpful Senior Marshall gave us the green light. We walked back ready for the first practice. This was when the kill switch came back to haunt us. After only two laps Andy began suffering an intermittent electrical fault, only rectified by judicious waggling the kill switch with his thumb. This couldn't go on forever, and after a few threatening intermittant faults, eventually the bike stopped all together. This may have been a blessing in disguise as we also uncovered a few issues with the front brakes. The electrical fault was easily solved and a new brake lever bolt was installed. The next problem surfaced during Sunday practice; the re-jigged front brake locked itself on. Being stuck, unable to move, with racers passing either side at full-chat, must have been a brown-pants moment. Enter stage right the recovery van, again! Upon its return the brakes were finally sorted by replacing the master cylinder (Thanks Dave) and using new, not sludge brown, brake fluid. After all the traumas we did the only sensible thing and retired to the pub. We had a good laugh with Ash, Nick, Sam and Liam, mostly arsing about with our new, sponsor provided, Buffs, drinking beer and eating chips.

The race on Sunday, by comparison to the previous days disaster, was slightly anti-climactic as everything worked more or less as it should - no crashes, no breakdowns. Andy finished, albeit in a foul mood. The borrowed bike was still rather underpowered compared to the rest of the field (sixteenth out of twenty six starters is OK, isn’t it?). Perhaps our rather poor showing could also be attributed to a lack of confidence after a fairly fraught weekend. However, we are supremely grateful to Steve for his loaning us the bike. Thanks, you're a gent!

And very sorry for smashing it up! We promise it will be returned (more or less) as we got it!

When we next come out to play we should have the ‘real deal’ bike ready, and I think we will both be disappointed if times/positions don’t improve.

See you at Brand’s…………..in July!

Down... But Not Out!

A team without a bike is like a Friday night without a kebab. Rubbish!

The Tigcraft is still in need of a bit more attention; the chilli sauce, if you will. However, the motor's in its final position, the controls are getting there, and some parts are winging there way in from far off lands with a good exchange rate. Not having the bike for this first Supermono weekend at Snetterton makes us Glum and Glummer; however our good chum SteveL has stepped into the breach to lend us his trusty track iron forthe weekend.

Hurrah!!

Moreover, he put a fair bit of graft in last week to get it back in one piece. Thanks a lot Steve, you're a gent. We are no longer glum, and Boyd will make you a cup of tea and a fresh cream canape over the weekend in the paddock.

To get it race legal, we needed only number boards, a bit of lockwiring, some attention to the fairing, a kill switch, and that's about it. We've changed the sprocket for Snetterton's long straights.

Like our Goode mate John, its a TZR250 chassis, with a 640 Yamaha motor. Its not the easiest to access the motor, so I am glad we didn't have to do any real work.

Steve reckons it was raced about 10 years ago in this class. Either way its a step up for me. Its got an ally tank (so it must be good), and I am finally dragged kicking and screaming into the 1980s with a monoshock rear end...

With a little paint and some stickers we reckon she looks so good that we've decided on just that colour for the Tigcraft when she finally graces a circuit near you (sometime!)

See you at Snetterton? We're #16, look for a non-beutiful ex-ambulance in the padoock. Boyd will be serving the cream teas in a french maid outfit...