dt175mx done blowed up
Day started well, planned to put on tyre and fit temp gauge. you can see the off road tyre was getting quite chewed.
Popped out for milk later and well i might have spanked it a bit hard, for those that don’t know 250C is melting aluminium time, if it reached 238C at the spark plug it got well hotter than that. and i wasn’t quick enough on the clutch.
I have my suspicions about that exhaust port, it’s a couple of mm lower on one side, and the high corner is the one that seized, to much exhaust T.A on a air cooled bike makes it run hot and lose power, have to find what the stock port should be!
So eh, time to make one of those spare bikes go? James helped!
More tuning to come of the DT, i had too much fun and need a two-stoke permanently in my life, it a new house rule.
DT175MX new pipe
New pipe fitted, from yambits, quite inexpensive, really gave it a proper powerband up top super entertaining to ride now. and not because the brakes are suddenly not up to the job
midrange is a little bit weak, or it was me just tip toeing about since the noise is really loud now and i don’t want to piss my neighbours off.
OF COURSE I PUT IT ON UPSIDE DOWN FIRST TIME
also note the stud on the right was buggered at some point, 10mm stud upgrade! for only one side!
 
Shots down the barrel, this is as low as i can put the piston, transfers are still shrouded, so lifting the barrel will work great.
but only after i find a better combustion chamber, blaster ysf200 head on the right is 6x97mm and the DT on the left is 6x93mm, neither head is a performance head, the offset squish was terrible idea and the tiny chamber and buried plug of the blaster won’t work too well at higher output.
it175 d/e/f will fit but are over 40 years old and a little expensive, i think the DT175 84-96 might fit, but i can’t find good pics.
DT175 tuning work
So time for some DT love
Kick start doesn’t quite fit, a s/h one is quite expensive and a new pattern one broke immediatly.
Stock filter is long gone, this works well enough, no change of rain water getting in i think.
had issues with the pilot jet acting lean, it was a little bit of rust, blew through no worries
Previous bodge job, it works so i’ll leave it.
Further work needs a stand, batterys are heavier than the bike.
Blaster 200 head, it was cheap, but the studs don’t line up 🙁 really need a better combustion chamber/centralised bowl and squish band for any performance gain.
Offset inlet, don’t like that either, can change for a rd350 one (aircooled i think) but i’m worried the PWK will then hit the case, airbox will need a lot of work to fit a filter then.
Shiny Silencer
Jetting notes
Needs a video soon.
the yearly update…
Just under a year since the last update, gotta find an easier way to post here,
anyway here’s a request, yes thats the rxs100/ysr50 back there, no it’s not coming out.
during lockdown i remember to take short spins every night for my mental health. New fav is this dt175mx, lots to do, probably never do it tho!
shed clear out
After rearrange, started work again on the rg.
Expensive, but now the shed (near 5 years since i bought it) has power, got a armoured cable, ethernet, separate breaker switch and this lovely light switch installed!
Really got to get back into this again, but projects are at an all time slow with life and other boring stuff happening.
Back to the darkside.
Some Rg125 bits first, the stock four pot is a great caliper, but pretty heavy, measure against another four pot i had lying around.
So lets upgrade to the two pot sliding caliper! ok that make little sense, but lightness comes first when you have can’t have more power.
This drain nozzle on the bottom of the airbox is the only part of the bike that hits the s1000rr shock. specifically the rubber tube thats attached to this.
Since the depth is fine i just heated it with as heat gun and slowly squished it shut.
Next i started to take a look at mounting the top fairing, stock head lamp cage hit the brake lever, looking into ways of remaking the whole lot out of aluminium.
So enough of the crap piles, my two new bikes are a freshly restored DT175MX..
..and yet another cbr6! gah actually this is only a loaner, couldn’t stand the gb400 any more so although i know i should not go back, i went back, the darkside has tight suspension and shiny bodywork.
carbs needed a little clean from sitting so long, i had the seat/side panels/tank/airbox and carbs off quicker then my dad re installing the dt175 rear wheel, he didn’t know it was a race but a win is a win.
Bling!
So very distracting.
tiny bit of noise off of the camchain tensioner, i think my old cbr6 had a different shape, may change over.
Got those blind holes tapped with the help of a snapped tap, very happy to see it on, less happy when i realised i hadn’t taken note of the timing marks..
Bench cleaned for the new head, gotta copy the porting over from the race head since that was so wildly successful.
Complete head cost €16, will those valves stand the abuse?
Cub 90 head work
Bought tools, this’ll help with foul-strokes.
speaking of the buggers, dissembled the c70 head.
Lovely isn’t it?
ports not touch much, i wonldn’t have shaped it like that
scrub scrub
polish polish, why? bored i suppose, now i have a head that could be used in a pinch.
removed the flywheel and future supercharge bracket, it’s possible my previous issues might be coil related, as the coils were off a lifan, and this engine is a zongshen.
borrowed the c70 IRK
all stop, have to gather some tools and some courage to tap these. please don’t hole the cases!
can you tell what my next bike maybe?
i consider this head a minor upgrade, the stock head and very offset plug and bowl.
tired of four stokes, so back to the rg125! deep breath, measure once and cut!
Repeat after me, angle grinder is a precision tool.
Looks good from that angle.
Fit’s here too.
bit wide here, but nothing is perfect.
Rust is lighter than carbon fiber.
Prep? nope. Race? yep. Boom? YEP!
Got a three hour enduro race on at the local go-kart track, watergrasshill nifty fifty 2019Â https://www.adventurepark.ie/
So a working bike is necessary! Need this to stop leaking, first attempt with carpet tak failed to no surprise.
JB-weld that fecker.
Special sauce also known as dihydrogen-monoxide, very important for re-magnetizing over heated inner rotor kits.
spent far too long making the side cover fit, and then ditched it in the end.
Ready to go? super light weight carbon end can fell off, so a rg125f end can was pressed into service. it was very very heavy.
Had a great race, all 27 minutes of it!
Some might say that taking on a 3 hour endurance race was too much for my old ass, and my only graceful way out was to select first while flat out in second at 10Krpm. Four times.
i think i just hadn’t got used to the new gear change setup
Took engine apart in the paddock, always wanted prove it was a 86cc in front of the other racers
Lovely destruction.
From last to sixth in the first lap, then i led for six laps before blowing up. proved i’m the best, just didn’t have to go the whole way to prove it.
Fastest laptime of the honda engines. Funkie Junkies have a YX of unknown CC with some honda cases slapped on the outside. Chicken Chasers were more open about it they have a YX120.
A Fish Called Honda (thats me!) is/was running an 86cc, next was Team Cider with a 107cc, then Classic bikes with their 114cc. All honda based, i’m the best
I’m stole the trophy because i’m also the sneakiest.
ok when i say stole i really mean traded my DNF prize of a Rolo easter egg. nice.
Divorce your bike?!
More throttle housing fixing, the cheapo epoxy didn’t set, probably not mixed right, so scrapped it all off and put some honest to god JBweld on it.
Then test painted it with all the colours i had.
the only good bit of paint was the cyan one, the red reacted and the yellow had a clogged nozzle, whatever, the guys in front will know i’m coming.
Investigating more front clonks, turned out this bush was melted from way back in 2013 when the bike was burnt out. Pic doesn’t show it great, but the metal sleeve is quite offset.
Where’d the rest of the packing go?
didn’t have any replacement bushings about the place.
So, a bit of floor mat (as seen in the background) shoved in under the sleeve and trim off the excess burnt bit’s, it’ll be grand.
could not get the other shock off, the bottom arm bolt was well stuck in there, no unnecessary movement of the shock so i left it..
In some major sad news the cbr6 is off back to the pile from which it came. 12 years and 10 months of service, touring, track days, pizza delivery, daily commute. I think the rear wheel is the only original part now.
It could be fixed again, but after near 13 years of continuous use it has to die now, you gotta move on. ‘still cried tho.
and it was fecking hard to look back over all the pictures, mostly of the cbr smashed up.
what to replace it with eh?
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.. 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.
