Nifty fifty 2019 went ahead without me, sick wife meant no fun for me, however it was hilarious hearing all about how the pro racers did in my absence.

dead last, crashed twice and jumped the start. first ever restart in nifty fifty history afaik.

also they stopped racing because it would not go forward. not sure how they could not see that the front sprocket fell off…

Anyway, my dads new engine worked well so the old stock 70 is now surplus, mine now!

Poor thing.

88cc head, never got it running right for the race and took it all out for 86cc the day before the race.

c70 head, same head e22 as on my 90, except for all the missing chunks, and the sealing surface. this is after i abused the fuck out of it with a plank of wood and some sandpaper.

note the exhaust valve, just a bit burned!

easy repairs first for the race bike, throttle housing snapped, looking closely it was cracked a long time ago and only let go now.

also found another old crack, load of epoxy glue lathered on and it’ll be grand

Next thing is the gear change, what i had worked great for the manual 4 speed, but the auto clutch in the three speed is quite banjaxxed, and needs a bit of force to change gear.

so the lever could be a little longer, easily done. but the rod also needed to be longer, not having the right tools i done a bang up good job with stuff i found on the floor, quite literally.

Slicks for our not very good pitbike we intend to race against some quite good pitbikes..Ā  more on that later.

24mm cvk gy6 carb choke delete

So the new carb for the 88cc racer looks great but i don’t have a 12v supply to power the fuel enrichment circuit or choke. because race bike.

off it comes then! easy to bolt off, without power the needle is in the open position, you can see it here in the middle

pre cracked from the factory! probably happened on delivery, would be mad if i ever intended to use it.

the insides, it can be unscrewed, but it is glued in place so the housing will crack.

took the needle and it’s barrel, place it fully seated in the metal housing, covered the the holes on the side with some tape in case of leaks and globed in some two-part epoxy

Waiting for that to harden up now before i bolt it on and test.

88cc head porting part deux

So to start with this head is off a 107cc, it has a large angled squish band and more meat and length to the inlet, it also uses the longer cam here:

pic of the stock intake, horrible casting, spring seat protrudes really far into the throat. pretty much the same as a stock honda 90 head.

Valve seats first, much sand paper and course lapping compound. crap job, so i went back to taking lumps out of the intake.

raised the port roof, smoothed down the spring seat hump

i say smoothed…

back to vavles seats

after many many little bits of sandpaper and some help from a drill to spin the valve, the seats are good enough.

Porting is complete, spent more time opening the valve seat throats, they did not match the head very well at all, also widened the port where the stem sits, i could do better but i do i need to spend that much time and foul-stroke?

24mm carb fitted, note how close the bowl is to the head, i think it would not fit a stock 90 head, but it fits this one so i’m all ready!

Race bike needs both brakes, i don’t have a two foot long foot so to match my rear sets i gotta make a brake pedal. and i don’t have a lotta spare metal lying around so the original super tucked in pedal will have to be sacrificed.

scraps of metal found and half the day spent poking at stuff

original pin chopped down and welded to frame as pivot.

Discovers my nice inverter arc welder is actually a piece of shit. i thought it was damp rods, but no, it’s just shit. super cheap tiny AC buzz box welder worked flawlessly.

Nope! pushing the rod is not going to work, feck. problem for the next day.

you know them niggly problems that take years off your life? this wasn’t one thank feck it, converted the throttle cable from a tiny nib thats supposed to act on the carb slide, to a…

..Large round nipple, yeah suck it SEO.


things to do before race day on the 23rd:

lots, not gonna lie and attempt to make a list, i just have lots to do and tools to buy.

88cc head porting

Race is soon, need faster engine, orders parts asap!

24mm cvk carb and inlet manifold, a second hand 1980’s honda rs250 foot peg, rasps for the dremmel, better quality air filter (old one is barely hanging in there) and a 38 and 39 tooth rear sprocket.

Engine out! real pleased at how easy that has become.

head off, inspection, and i’m a happy bunny!

valves didn’t hit the piston and the piston didn’t hit the head.

chamber is really black due to me running so rich all day on the new years run, still no real damage.

valve seats are still fucked, who’s surprised?

got all prepped to flow things and i realise.. that i put the collet and nut in a safe place to avoid the smallie from taking it off (as he would occasionally run about the place with it) and choking on it. A really really safe place.

I did in the mean time get a loan of a dremmel and made a start on flowing the head, piccies next time!

cub90 test

Can you tell what it is yet?

Yep, stop ya stones getting in ya engine!

All set for the new years day test run

..and i ran out of fuel, twice, appears that setting the L needle really far out wasn’t a good idea, who’d have thunk it?

anyway after farting about all day, i set the L needle where it should be and it still didn’t run great, in 1-3 it would pull like it had a power band, but falls flat in fourth. got better as the day wore on, keep forgetting there is plenty of running still to do on this cylinder piston and rings.

couple of backfires/pops here and there too, indicating what i already knew, the valve seats needs fixing.

regarding the lack of up top power, the head isn’t ported so with that done it may help alot, or it could just plainly be the gearing, 24mm CVK carb on the way in case we need more breathing. it’s also much slower at 81kmh rather that 87kmh

Vibration! much reduced which is really a very handy thing for an endurance racer.

Saw this on the run, hydraulic drum brake mod,


rg125 on hold

I like cooking alot, but my knifes selection left alot to be desired, so i made a better one!

polished up nicely with some 1200 grit, already feel the urge to get a 2000 whetstone from amazon.

Rg125 raditor, considering my options, do really want an upgrade.

Everything stops when the music isn’t right, poked the wires and we were back on track.

Beat that straight

this bit needed more finesse, less hammer

a selection of tidied painted and bought bits

Helper number one fitted it all up!

And now the rg is on hold because this cub90 is now in the shed, gotta run it in on the new years day run and lots of other bits need completing before race day.

Don’t say nice things about my bike

Making the attempt to do weekly updates, i feel i’m missing notes with large drops.

Got that tab moved forward 30mm, a little too far, but it’s ok the welds are shit, no penetration with sticks for sheet metal šŸ™‚

After i said nice things the other day about the cbr6, fecking clutch cable broke, this is off a bros 400, inner is too long so this temporary mess was done just to get me moving.

probably stay like that all year now

the netbook, the 88cc and the rg125

So first a little update on the netbook situation, bought a dell 2120, super cheapo, didn’t realize they came in single core models..

upgrade time!

Whole motherboard upgrade,

*eyes wwan port* pci-e ssd?

failing purple msi wind gave up its ram and ssd to my new chunk top.

Anyways back to the fun stuff, clutch carb, and rev counter installed.

They don’t work, but they are installed..

Check out the rubbing from the carbon fiber pipe on the shock šŸ™‚

new old pipe is the best pipe ever.

springs installed to keep choke from closing accidentally, and the throttle from accidentally staying open šŸ˜€

Ford bits installed!

These will be where i install the rear sets, next week probably, no mig wire!

Pump and switches for runner 180 water pump mod.

Onto the Rg125, gs500 37mm forks fitted up quite nicely,they are a ton lighter and 0.59kg/mm springs seem to suit it

lock stops, steering lock, everything perfect.

Top yoke is ugly, but what are you gonna do?

Whole thing is sitting a bit high, we’ll fix that.

gs500 wheel is drop in replacement, if you needed to keep the stock gsxr forks.

Disc is a 320mm vs 310 and the speedo drive is a smaller outer diameter

Replaced the lower bearings with ebay specials, no rubber seal, unlikely to do so many miles i’ll need that. Dogbones need extending to lower the back about 3cm according to my calculations

extended 6mm, or at least i planned to, actually got 5mm, best i could do with a angle grinder and a stick welder.

Dropped fork 50mm, threw on the clipons i bought, i bought 38mm clipons cause i’m an idiot, rushed to buy them, nothing an angle grinder and some filing couldn’t fix. I like the radial master cylinder.

Onto some plastics mock up.

Fitting the under tray and some of the electrical loom

Probably gonna have to tidy that, quite heavy too!

Big gaps, need to move tail piece forward 30mm

2T oil tank i don’t think will fit under the plastics, thinking of making a tank and putting where the batter lived.

Moved forward here,

Much tidier, gotta weld it up next time i’m out there.

And also my cbr was sick!, ran rough as feck, very close to happily dumping it in the spares pile (already on DoneDeal looking at other bikes) but then we found the blanking plug for number three vacuum port, fallen off an sitting in the vee behind the cylinders… pop’dĀ  it back on and the cbr’s butt was saved again for another day.

88cc engine swap

Cleaned new engine, a bit, didn’t actually put any effort in.

86cc racer looking resplendent in battle scar red and rust.

last race at watergrasshill saw this tab for the leg shield break off, wouldn’t be a problem normally except i can’t find the tab. Have to make another.

built this in 2014, it’s done well to be fair, sold now to my dads team who’ll slap a smaller class restricted carb on it and attempt to win the stock class.

Engine vibes? i knew the engine was very vibey, my first though was loose engine bolts, now i know it was a loose engine bolt!

Tillostson looks purposeful.

Plate that some of the previous electronics were mounted on, it fell off a year or two ago and was just rattling around under the tank, finally gone. Can still see the melted plastic from this bikes previous life as a bonfire.

Stihl 090 90Ā° elbow on the way, gotta flow it a bit and attache a filter. also the throttle cable, i’m just ignoring that huge ass pain for now..

More Runner 180 water pump woes, not sure if i want to leave the impeller behind when i switch to electric pump.

Splitting cases isn’t that hard i suppose.

slap that 88cc together

Went with boring paint in the end, figured everything else is a bit mad, so tone it down.

Needs second coat and lacquer asap, but didn’t turn out that bad considering how much i hate paint prep

Order a very cheap radial master cylinder, wasn’t really surprised when i saw this shitty casting, at least only on the clamp part, the body seems ok. i hope.

VJ21 race fairings, strangely modded road ones, was expecting much more straight forward molds, ejit store sent me a smoked screen after i asked for a plain one. sigh. still rg125 ought to look much slimmer with these clothes on.

Race 88cc, in one piece now, gy6 88cc piston installed, used a 107cc head, of the two i had the 107 had better castings and i have a lumpy long cam for it, head with the smaller chamber used a shorter cam so i gave up on that.

very direct tillotson carb, should work great!

That is of course if i can get the valves to seat.

after some lapping there are still not so good, but alright for testing purposes!

new piston is much bigger then the stock 50(right), and has a lot more compression then a stock 107 (left)

perfect deck height.

107 head on right, you can make out the combustion chamber size difference, plus the extra cooling fins.

some Runner 180 info, gotta build up an electric pump kit, toyota prius inverter pumps are perfect, but finding a switch to turn it on is not cheap, so i’ll probably settle for a switch.

uprate the cbr6 brakes, eventaully.

Next Page »