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It's finally time - Formula Prostock B6


zedhead

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4 minutes ago, zedhead said:

Perhaps not a bad idea to take a look at the head, although no "tidy up" allowed, boggo stocko only!

But a thorough decoke and a little lap dance :banana: for the valves will maximise what you've got ,what about slotted cam sprockets for timing the cams...

Edited by DAZ
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9 hours ago, bluedog59 said:

First rule of racing :

Read the rule book, what it says and more importantly, what it doesn't say.

 

I remember way back reading an article about formula ford racing that the top engine Builders would check crate loads of cams for the "one" where the tolerances in machining have a little more lift ,same with conrods find the lightest set,rocker arms that had the highest ratio, Etc the rest was used in engines for kit cars and series that allowed modification, mind you back then factory machining and assembly was nowhere near the standards of now or even the 2000s and a blueprinted engine had a definite improvement over a Friday afternoon or Monday morning one. I also read about acid porting,where they fill the ports with acid for an amount of time it dissolves the metal at a set rate ,and leaves a stock looking but larger port still with casting lines etc,just a bit bigger there's some sneaky buggers out there :D

Edited by DAZ
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On 2/20/2023 at 6:19 PM, zedhead said:

Perhaps not a bad idea to take a look at the head, although no "tidy up" allowed, boggo stocko only!

Did say take head off to it, you got to be dam lucky to get it out and now it may be hard as nails with all the heat thats been put in the bolt.

I recently got bolt out with lots of heat and thread did not look great after and decided there and then drill rest instead.

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  • 2 weeks later...

Exhaust on, belly pan fitted, spare ignition switch fitted, remote fuel set-up, new battery... it's time...

Er, no it's not. Spark & fuel but spin spin, spin...

Battery on charge.

Turn to bleeding brakes. Fluid in rear, back-bled using syringe. Nothing at the pedal. Leave it to sort itself and move to the front. Back-bled left caliper, already resistance at the lever. Back-bled right caliper and bingo, lovely!

Return to rear,  fill up reservoir and have a go at bleeding. Pump, pumpity pump. Splurge. Plunger falls out of rear master cylinder dumping fluid everywhere. Fucker. Master cylinder off, cleaned and rebuilt with the circlip properly fitted to it (hopefully) doesn't decide to drop its guts again. 

I wonder of the freshly-charged battery will make a difference to if it starts? No.

Go inside for a brew, sit down to watch Pottery Throwdown (guilty secret), knock magazine off side of sofa and knock hot chocolate all over carpet.

Fuck it. Went to bed in a strop...

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  • 2 weeks later...

Those of you who see my social media will have seen that it eventually stated, and ran, after a fashion... Anyway, carb refurb kit ordered in the hope that it'd turn up before my appointm,ent with the dyno (two days before first meeting test day!)

Bellypan tweaked a tad where it was touching the exhaust. Seat pad fitted (badly). Number board fitted, and on/off switch relocated so the number board would fit right.

Rear brake still not bleeding up. Tried everything but no luck...

Morningt of dyno day, carb kit turned up so carbs off, new shiny bits fitted, carbs back in (ballache with standard airbox) and straight over to Black & White Bikes for dyno, without event pressing the starter...

Paul at B&W sorted out static sag, preload added to YSS shock and spacers added top forks, now 30mm (loaded) sag front and rear.

Time for dyno and.... it started first press of the button, even ticked over, re-fucking-sult! After some jiggling with clutch cable adjuster (massive clutch slip to start with) a rather pleasing smooth power curve amounting to 68bhp and even a good AR too. Only non-standard bits are the 102.5 mains, exhaust and air filter.

Some issues noticed though. Slipping clutch may have goosed plates so time to whip the clutch out of spare engine just in case. The airbox had popped off the back of the carbs. the thottle tube was spinning on the bars (yep, previous owner had griound off the locating stub when fitting aftermarket bars). The oil cooler has a weep (have brand new copt cooler in b ox in garage), and an oil drain tube at the front of the block looked as though it was weeping too...

All of those sorted - including the rear brake which need every trick in the book thrown at it, including warming up the caliper, hose & master with a hot air gun) - and out of the garage at 1am this morninig. Just need to load it all up and head to Brands tonight, leaving the race numbers and additional stickers (including all-important Winged Hammer) to be put on trackside...

I am very tired.

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  • 2 weeks later...

Okay, so a delayed race report from Brands Hatch...

Test day was just that - testing. The bike had only been run on the dyno two day previously, so there were a couple of very late nights sorting out some bits and bobs.

Dyno had shown 67bhp (class limit is 80bhp), with near perfect fuelling with the 102.5 mains that I'd fitted (standard are 98 outside two pots, 100 middle two). Massive clutch slip when the first dyno run started was merely very bad clutch cable adjustment.

First session, feeling my way around, bike feels really harsh with the extra preload Paul at Black & White Bikes has set it up with, but then I was riding it like a road bike. And then the gear shift linkage fell off and disappeared into the gravel.

A new shift rod (from AR Racing, who were also busy fitting wets to my spare wheels) and some all-thread blagged from a fellow newbie and I was out for test session 3. That went better, feeling my way into a groove and bike feeling better now I was riding it harder. Session 4 was the same.

Saturday warm-up. Oh, some of these guys on Bandits are quite quick aren't they... Qualifying was really good fun, actually starting to know when the track goes, although clutch slip early on was a surprise. Qualified 17th on the grid. Not last!

First race, and nerves only appeared when my bladder told me it needed emptying several times in the 15 minutes before call-up. Surprisingly calm on the grid, for the warm-up lap (with clutch slip appearing several times) and for the start. First two laps saw me going backwards on every straight thanks to clucth slip that disappeared once there was a lot of heat in the motor. Although misfire creeping in at end of race. And I finished my first race. No idea what position. Don't care. MASSIVE grin.

Spoke about misfire to fellow newbie - check the fuel line isn't kinking when hot. It was. Resolved by cutting it shorter. 

Forecast was dire for Sunday, so wets fitted. Well. Wheels fitted but front calipers wouldn't go on. Disc spacing different. Eh? So swap discs over from 'dry' wheel and bingo. Seems that the discs I got with the spare Bandit wheels weren't Bandit discs.

Anyway, 16th on grid (from race one) and tippy toe round wondering how much grip wets actually give. Clutch slip again as forgot to warm motor up enough. Still ace fun but felt that I was riding like I was on the road...

Race three also wet, but not raining now. Engine warmed up when previous race was called. Warm-up, grid (16th again) etc. No clutch slip except on the start-finish at end of lap one. Had ace battle with fellow newcomer all race, swapping places and learning that wets have a ridiculuous amount of grip but will start to move around on a dry line... THIS IS FUCKING AWESOME!

End result, one very happy bloke....

 

 

 

 

.... oh, yeah the Bandit Challenge class has sub-divisions, with Rookie and Senior classes. As I fit into the latter group, I was a little surprised to discover I got three third place cups t take home! And, no, there weren't just three Seniors racing at Brands....

This will undubtedly get a little harder as the season progresses as there are some very experienced Seniors who dip in and out of the series through the year and who weren't racing at the first round...

Edited by zedhead
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Oh, and there was a dyno test after we came off track at the end of qualifying - mine made 73bhp, several other newbies' bikes made 2 or 3bhp more...

Finesse could be found in gearing changes I reckon. That and actually riding it a bit harder....

Edited by zedhead
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Excellent report @zedhead glad you got some silverware, I'm sure you'll be fettleing and perfecting your set up . interesting how some others were 5% more power,,and the class limit is 10% more,  must be some donkeys to be found somewhere...maybe the OSS collective can help you figure where the buggers are. keep the updates coming (y)

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1 hour ago, DAZ said:

I believe it should be 12v through the Orange and green wire ,black and white is an earth and black and red to the cdi via the headlight ... Do you still have a headlight? 

 

No headlight now - all lights must be removed in race regs.  It was working fine, but I noticed at the start of race 3 that it'd stopped working... thanks for the info regards wire colours etc though, I can test when I'm home next week...

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